Mol Plant , IF:12.084 , 2021 Feb , V14 (2) : P285-297 doi: 10.1016/j.molp.2020.11.011
MPK14-mediated auxin signaling controls lateral root development via ERF13-regulated very-long-chain fatty acid biosynthesis.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China; College of Horticulture, Qingdao Agricultural University, Qingdao, Shandong 266109, China.; The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China.; State Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Taian, Shandong 271018, China.; State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China.; State Key Laboratory of Crop Biology, College of Forestry, Shandong Agricultural University, Taian, Shandong 271018, China.; The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China. Electronic address: dingzhaojun@sdu.edu.cn.
Auxin plays a critical role in lateral root (LR) formation. The signaling module composed of auxin-response factors (ARFs) and lateral organ boundaries domain transcription factors mediates auxin signaling to control almost every stage of LR development. Here, we show that auxin-induced degradation of the APETALA2/Ethylene Responsive Factor (AP2/ERF) transcription factor ERF13, dependent on MITOGEN-ACTIVATED PROTEIN KINASE MPK14-mediated phosphorylation, plays an essential role in LR development. Overexpression of ERF13 results in restricted passage of the LR primordia through the endodermal layer, greatly reducing LR emergence, whereas the erf13 mutants showed an increase in emerged LR. ERF13 inhibits the expression of 3-ketoacyl-CoA synthase16 (KCS16), which encodes a fatty acid elongase involved in very-long-chain fatty acid (VLCFA) biosynthesis. Overexpression of KCS16 or exogenous VLCFA treatment rescues the LR emergence defects in ERF13 overexpression lines, indicating a role downstream of the auxin-MPK14-ERF13 signaling module. Collectively, our study uncovers a novel molecular mechanism by which MPK14-mediated auxin signaling modulates LR development via ERF13-regulated VLCFA biosynthesis.
PMID: 33221411
EMBO J , IF:9.889 , 2021 Feb , V40 (3) : Pe106862 doi: 10.15252/embj.2020106862
Modulation of plant root growth by nitrogen source-defined regulation of polar auxin transport.
Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria.; Bioresources Unit, Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria.; Centro de Biotecnologia y Genomica de Plantas (CBGP, UPM-INIA) Universidad Politecnica de Madrid (UPM)-Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), Madrid, Spain.; Pontifical Catholic University of Chile, Santiago, Chile.; BPMP, CNRS, INRAE, Institut Agro, Univ Montpellier, Montpellier, France.
Availability of the essential macronutrient nitrogen in soil plays a critical role in plant growth, development, and impacts agricultural productivity. Plants have evolved different strategies for sensing and responding to heterogeneous nitrogen distribution. Modulation of root system architecture, including primary root growth and branching, is among the most essential plant adaptions to ensure adequate nitrogen acquisition. However, the immediate molecular pathways coordinating the adjustment of root growth in response to distinct nitrogen sources, such as nitrate or ammonium, are poorly understood. Here, we show that growth as manifested by cell division and elongation is synchronized by coordinated auxin flux between two adjacent outer tissue layers of the root. This coordination is achieved by nitrate-dependent dephosphorylation of the PIN2 auxin efflux carrier at a previously uncharacterized phosphorylation site, leading to subsequent PIN2 lateralization and thereby regulating auxin flow between adjacent tissues. A dynamic computer model based on our experimental data successfully recapitulates experimental observations. Our study provides mechanistic insights broadening our understanding of root growth mechanisms in dynamic environments.
PMID: 33399250
Curr Biol , IF:9.601 , 2021 Feb , V31 (4) : P892-899.e3 doi: 10.1016/j.cub.2020.11.026
Alternative Splicing Generates a MONOPTEROS Isoform Required for Ovule Development.
Dipartimento di BioScienze, Universita degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.; Dipartimento di BioScienze, Universita degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy; INGM, National Institute of Molecular Genetics "Romeo ed Enrica Invernizzi," 20122 Milano, Italy.; Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, the Netherlands.; Dipartimento di BioScienze, Universita degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy. Electronic address: lucia.colombo@unimi.it.
The plant hormone auxin is a fundamental regulator of organ patterning and development that regulates gene expression via the canonical AUXIN RESPONSE FACTOR (ARF) and AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) combinatorial system. ARF and Aux/IAA factors interact, but at high auxin concentrations, the Aux/IAA transcriptional repressor is degraded, allowing ARF-containing complexes to activate gene expression. ARF5/MONOPTEROS (MP) is an important integrator of auxin signaling in Arabidopsis development and activates gene transcription in cells with elevated auxin levels. Here, we show that in ovules, MP is expressed in cells with low levels of auxin and can activate the expression of direct target genes. We identified and characterized a splice variant of MP that encodes a biologically functional isoform that lacks the Aux/IAA interaction domain. This MP11ir isoform was able to complement inflorescence, floral, and ovule developmental defects in mp mutants, suggesting that it was fully functional. Our findings describe a novel scenario in which ARF post-transcriptional regulation controls the formation of an isoform that can function as a transcriptional activator in regions of subthreshold auxin concentration.
PMID: 33275890
Curr Biol , IF:9.601 , 2021 Feb , V31 (3) : P555-563.e4 doi: 10.1016/j.cub.2020.10.077
NO GAMETOPHORES 2 Is a Novel Regulator of the 2D to 3D Growth Transition in the Moss Physcomitrella patens.
Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK. Electronic address: laura.moody@plants.ox.ac.uk.; Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.
The colonization of land by plants was one of the most transformative events in the history of life on Earth. The transition from water, which coincided with and was likely facilitated by the evolution of three-dimensional (3D) growth, enabled the generation of morphological diversity on land. In many plants, the transition from two-dimensional (2D) to 3D growth occurs during embryo development. However, in the early divergent moss Physcomitrella patens, 3D growth is preceded by an extended filamentous phase that can be maintained indefinitely. Here, we describe the identification of the cytokinin-responsive NO GAMETOPHORES 2 (PpNOG2) gene, which encodes a shikimate o-hydroxycinnamoyltransferase. In mutants lacking PpNOG2 function, transcript levels of CLAVATA and SCARECROW genes are significantly reduced, excessive gametophore initial cells are produced, and buds undergo premature developmental arrest. Mutants also exhibit misregulation of auxin-responsive genes. Our results suggest that PpNOG2 functions in the ascorbic acid pathway leading to cuticle formation and that NOG2-related genes were co-opted into the lignin biosynthesis pathway after the divergence of bryophytes and vascular plants. We present a revised model of 3D growth in which PpNOG2 comprises part of a feedback mechanism that is required for the modulation of gametophore initial cell frequency. We also propose that the 2D to 3D growth transition in P. patens is underpinned by complex auxin-cytokinin crosstalk that is regulated, at least in part, by changes in flavonoid metabolism.
PMID: 33242390
Proc Natl Acad Sci U S A , IF:9.412 , 2021 Feb , V118 (8) doi: 10.1073/pnas.2018940118
Mechanism and function of root circumnutation.
Department of Biology, Duke University, Durham, NC 27708.; Howard Hughes Medical Institute, Duke University, Durham, NC 27708.; School of Physics, Georgia Institute of Technology, Atlanta, GA 30332.; Department of Plant Pathology and the Genome Center, University of California, Davis, CA 95616.; Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106.; Department of Biology, Duke University, Durham, NC 27708; philip.benfey@duke.edu.
Early root growth is critical for plant establishment and survival. We have identified a molecular pathway required for helical root tip movement known as circumnutation. Here, we report a multiscale investigation of the regulation and function of this phenomenon. We identify key cell signaling events comprising interaction of the ethylene, cytokinin, and auxin hormone signaling pathways. We identify the gene Oryza sativa histidine kinase-1 (HK1) as well as the auxin influx carrier gene OsAUX1 as essential regulators of this process in rice. Robophysical modeling and growth challenge experiments indicate circumnutation is critical for seedling establishment in rocky soil, consistent with the long-standing hypothesis that root circumnutation facilitates growth past obstacles. Thus, the integration of robotics, physics, and biology has elucidated the functional importance of root circumnutation and uncovered the molecular mechanisms underlying its regulation.
PMID: 33608460
Proc Natl Acad Sci U S A , IF:9.412 , 2021 Feb , V118 (8) doi: 10.1073/pnas.2023942118
Transcriptional control of local auxin distribution by the CsDFB1-CsPHB module regulates floral organogenesis in cucumber.
Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, 100193 Beijing, China.; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081 Beijing, China.; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081 Beijing, China wangchanglin@caas.cn suixiaolei@cau.edu.cn.; Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, 100193 Beijing, China; wangchanglin@caas.cn suixiaolei@cau.edu.cn.
Plant cystatins are cysteine proteinase inhibitors that play key roles in defense responses. In this work, we describe an unexpected role for the cystatin-like protein DEFORMED FLORAL BUD1 (CsDFB1) as a transcriptional regulator of local auxin distribution in cucumber (Cucumis sativus L.). CsDFB1 was strongly expressed in the floral meristems, floral primordia, and vasculature. RNA interference (RNAi)-mediated silencing of CsDFB1 led to a significantly increased number of floral organs and vascular bundles, together with a pronounced accumulation of auxin. Conversely, accompanied by a decrease of auxin, overexpression of CsDFB1 resulted in a dramatic reduction in floral organ number and an obvious defect in vascular patterning, as well as organ fusion. CsDFB1 physically interacted with the cucumber ortholog of PHABULOSA (CsPHB), an HD-ZIP III transcription factor whose transcripts exhibit the same pattern as CsDFB1 Overexpression of CsPHB increased auxin accumulation in shoot tips and induced a floral phenotype similar to that of CsDFB1-RNAi lines. Furthermore, genetic and biochemical analyses revealed that CsDFB1 impairs CsPHB-mediated transcriptional regulation of the auxin biosynthetic gene YUCCA2 and the auxin efflux carrier PIN-FORMED1, and thus plays a pivotal role in auxin distribution. In summary, we propose that the CsDFB1-CsPHB module represents a regulatory pathway for local auxin distribution that governs floral organogenesis and vascular differentiation in cucumber.
PMID: 33602821
Proc Natl Acad Sci U S A , IF:9.412 , 2021 Feb , V118 (8) doi: 10.1073/pnas.2017488118
Plant egg cell fate determination depends on its exact position in female gametophyte.
State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China.; State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072 Wuhan, China bobopx@whu.edu.cn.
Plant fertilization involves both an egg cell, which fuses with a sperm cell, and synergid cells, which guide pollen tubes for sperm cell delivery. Therefore, egg and synergid cell functional specifications are prerequisites for successful fertilization. However, how the egg and synergid cells, referred to as the "egg apparatus," derived from one mother cell develop into distinct cell types remains an unanswered question. In this report, we show that the final position of the nuclei in female gametophyte determines the cell fate of the egg apparatus. We established a live imaging system to visualize the dynamics of nuclear positioning and cell identity establishment in the female gametophyte. We observed that free nuclei should migrate to a specific position before egg apparatus specialization. Artificial changing in the nuclear position on disturbance of the actin cytoskeleton, either in vitro or in vivo, could reset the cell fate of the egg apparatus. We also found that nuclei of the same origin moved to different positions and then showed different cell identities, whereas nuclei of different origins moved to the same position showed the same cell identity, indicating that the final positions of the nuclei, rather than specific nucleus lineage, play critical roles in the egg apparatus specification. Furthermore, the active auxin level was higher in the egg cell than in synergid cells. Auxin transport inhibitor could decrease the auxin level in egg cells and impair egg cell identity, suggesting that directional and accurate auxin distribution likely acts as a positional cue for egg apparatus specialization.
PMID: 33597298
J Hazard Mater , IF:9.038 , 2021 Feb , V413 : P125402 doi: 10.1016/j.jhazmat.2021.125402
Diclofenac modified the root system architecture of Arabidopsis via interfering with the hormonal activities of auxin.
SELS Center, Division of Biotechnology, College of Bioresources and Environmental Science, Chonbuk National University, Iksan 54596, Republic of Korea.; SELS Center, Division of Biotechnology, College of Bioresources and Environmental Science, Chonbuk National University, Iksan 54596, Republic of Korea. Electronic address: activase@jbnu.ac.kr.
Diclofenac, a pharmaceutical and personal care product, is accumulating in various environmental matrices worldwide. Increased irrigation has facilitated an influx of environmental diclofenac into agricultural products, which potentially threatens non-target living organisms. In this study, we demonstrated that diclofenac modified the growth and root developmental processes of plants by disturbing the activity of auxin, a group of major phytohormones. Exogenous diclofenac treatment retarded growth and induced oxidative stress in young seedlings of Arabidopsis thaliana. In the developmental perspective, diclofenac altered the root system architecture, which was also similarly observed under exogenous IAA (a natural form of phytoalexins) treatment. The effects of diclofenac on the root development of A. thaliana were mediated through canonical auxin signaling pathways. However, when diclofenac and IAA were treated in combination, diclofenac suppressed the activity of IAA in root system architecture. At the molecular level, diclofenac significantly inhibited the activity of IAA upregulating the expression of early auxin-responsive marker genes. In conclusion, diclofenac modified the root development of A. thaliana via interfering with the activities of natural auxin. These results indicate that diclofenac could potentially act as an environmental contaminant disturbing the natural developmental processes of plants.
PMID: 33626476
J Hazard Mater , IF:9.038 , 2021 Feb , V403 : P123946 doi: 10.1016/j.jhazmat.2020.123946
OsFTIP7 determines metallic oxide nanoparticles response and tolerance by regulating auxin biosynthesis in rice.
State Key Laboratory of Rice Biology, Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Zhejiang University, Hangzhou 310058, China.; Institute of Crop Breeding and Cultivation, Shanghai Academy of Agricultural Sciences, Shanghai 201403, China.; State Key Laboratory of Rice Biology, Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Zhejiang University, Hangzhou 310058, China. Electronic address: shiyongsong@zju.edu.cn.; State Key Laboratory of Rice Biology, Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Zhejiang University, Hangzhou 310058, China. Electronic address: yingchen2017@zju.edu.cn.
The widely application of metallic oxide nanoparticles (NPs) has led to an increase in their accumulation in farmland. Previous studies have found that the metallic oxide NPs have negative effect on plants development and growth. Nonetheless, the underlying mechanism of response to metallic oxide NPs in rice remains elusive. In this study, we show that rice FT-INTERACTING PROTEIN 7 (OsFTIP7) plays an essential role in NPs of CuO and ZnO-mediated physiological and biochemical changes in rice. Loss of function of OsFTIP7 reduced the toxicity of the NPs of CuO and ZnO to the seedlings by accumulating more biomass and chlorophyll contents. Furthermore, after high exposure to metallic oxide NPs, more indole-3-acetic acid (IAA) were determined in Osftip7 with higher expression of auxin biosynthetic genes than the control seedlings. What's more, IAA-treated seedlings displayed the similar phenotype as Osftip7 under high concentrations of NPs of CuO and ZnO. Taken together, the results substantiate that OsFTIP7 is involved in metallic oxide nanoparticle-mediated physiological and biochemical changes by negatively regulating auxin biosynthesis in rice.
PMID: 33264991
New Phytol , IF:8.512 , 2021 Feb doi: 10.1111/nph.17293
ZmSPL10/14/26 Are Required for Epidermal Hair Cell Fate Specification on Maize Leaf.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China.; Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
The epidermal hair and stomata are two types of specialized structures on plant leaf surface. On mature maize leaves, stomatal complexes and three types of hairs are distributed in a stereotyped pattern on the adaxial epidermis. However, the spatiotemporal relationship between epidermal hair and stomata development and the regulatory mechanisms governing their formation in maize remain largely unknown. Here, we report that three homologous ZmSPL transcription factors, ZmSPL10, ZmSPL14 and ZmSPL26, act in concert to promote epidermal hair fate on maize leaf. Cytological analyses revealed that Zmspl10/14/26 triple mutants are completely glabrous, but possess ectopic stomatal files. Strikingly, the precursor cells for prickle and bicellular hairs are transdifferentiated into ectopic stomatal complexes in the Zmspl10/14/26 mutants. Molecular analyses demonstrated that ZmSPL10/14/26 directly bind to the promoter of a WUSCHEL-related homeobox gene, ZmWOX3A, and upregulate its expression in the hair precursor cells. Moreover, several auxin-related genes are down-regulated in the Zmspl10/14/26 triple mutants. Our results suggest that ZmSPL10/14/26 play a key role in promoting epidermal hair fate on maize leaf, possibly through regulating ZmWOX3A and auxin-related gene expression, and that the fates of epidermal hairs and stomata are switchable.
PMID: 33626179
New Phytol , IF:8.512 , 2021 Feb doi: 10.1111/nph.17265
Brassinosteroid-BZR1/2-WAT1 module determines the high level of auxin signalling in vascular cambium during wood formation.
Department of Biology, Chungbuk National University, Cheongju, 28644, Republic of Korea.; School of Biological Sciences, Seoul National University, Seoul, 08826, Korea.; Theragen Bio Co, Ltd, Suwon, 16229, Republic of Korea.; Department of Information and Statistics, Chungbuk National University, Cheongju, 28644, Republic of Korea.; Department of Forest Science, Chungbuk National University, Cheongju, 28644, Republic of Korea.; Department of Horticulture, Hankyong National University, Ansung, 17579, Republic of Korea.; Department of Industrial Plant Science and Technology, Chungbuk National University, Cheongju, s28644, Republic of Korea.
The tight regulation of local auxin homeostasis and signalling maxima in xylem precursor cells specifies the organizing activity of the vascular cambium and consequently promotes xylem differentiation and wood formation. However, the molecular mechanisms underlying the local auxin signalling maxima in the vascular cambium are largely unknown. Here, we reveal that brassinosteroid (BR)-activated WALLS ARE THIN1 (WAT1) facilitates wood formation by enhancing local auxin signalling in the vascular cambium in Solanum lycopersicum. Growth defects and low auxin signalling readouts in the BR-deficient tomato cultivar, Micro-Tom, were associated with a novel recessive allele, Slwat1-copi, created by the insertion of a retrotransposon in the last exon of the SlWAT1 locus. Molecular and genetic studies by generating the gain- and loss-of-function tomato mutants revealed that SlWAT1 is a critical regulator for fine-tuning local auxin homeostasis and signalling outputs in vascular cambium to facilitate secondary growth. Finally, we discovered that BR-regulated SlBZR1/2 directly activation of downstream auxin responses by SlWAT1 upregulation in xylem precursor cells to facilitate xylem differentiation and subsequent wood formation. Our data suggest that the BR-SlBZR1/2-WAT1 signalling network contributes to the high level of auxin signalling in the vascular cambium for secondary growth.
PMID: 33570747
New Phytol , IF:8.512 , 2021 Feb doi: 10.1111/nph.17263
VviNAC33 promotes organ de-greening and represses vegetative growth during the vegetative-to-mature phase transition in grapevine.
Department of Biotechnology, University of Verona, 37134, Verona, Italy.; Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854-8020, USA.
Plants undergo several developmental transitions during their life cycle. In grapevine, a perennial woody fruit crop, the transition from vegetative/green to mature/woody growth involves transcriptomic reprogramming orchestrated by a small group of genes encoding regulators, but the underlying molecular mechanisms are not fully understood. We investigated the function of the transcriptional regulator VviNAC33 by generating and characterizing transgenic overexpressing grapevine lines and a chimeric repressor, and by exploring its putative targets through DAP-seq approach combined with transcriptomic data. We demonstrated that VviNAC33 induces leaf de-greening, inhibits organ growth and directly activates the expression of STAY-GREEN PROTEIN 1 (SGR1), involved in chlorophyll and photosystem degradation, and AUTOPHAGY 8f (ATG8f) involved in the maturation of autophagosomes. Furthermore, we show that VviNAC33 directly inhibits AUXIN EFFLUX FACILITATOR PIN1 and RopGEF1 and ATP SYNTHASE GAMMA CHAIN 1T (ATPC1) involved in photosystem II integrity and activity. Our results show that VviNAC33 plays a major role in terminating photosynthetic activity and organ growth as part of a regulatory network governing the vegetative-to-mature phase transition.
PMID: 33567124
New Phytol , IF:8.512 , 2021 Feb doi: 10.1111/nph.17261
Virus-induced phytohormone dynamics and their effects on plant-insect interactions.
Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou, 310058, China.; Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, 92521-0124, USA.
Attack of plants by both viruses and their vectors is common in nature. Yet the dynamics of the plant-virus-vector tripartite system, in particular the effects of viral infection on plant-insect interactions, have only begun to emerge in the last decade. Viruses can modulate the interactions between insect vectors and plants via the jasmonate, salicylic acid and ethylene phytohormone pathways, resulting in changes in fitness and viral transmission capacity of their insect vectors. Virus infection of plants may also modulate other phytohormones, such as auxin, gibberellins, cytokinins, brassinosteroids, and abscisic acid, with yet undefined consequences on plant-insect interactions. Moreover, virus infection in plants may incur changes to other plant traits, such as nutrition and secondary metabolites, that potentially contribute to virus-associated, phytohormone-mediated manipulation of plant-insect interactions. In this article, we review the research progress, discuss issues related to the complexity and variability of the viral modulation of plant interactions with insect vectors, and suggest future directions of research in this field.
PMID: 33555072
New Phytol , IF:8.512 , 2021 Feb doi: 10.1111/nph.17252
The microRNA476a-RFL module regulates adventitious root formation through a mitochondria-dependent pathway in Populus.
Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, School of Life Sciences, Southwest University, Chongqing, 400715, China.; Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, 400715, China.; College of Landscape Architecture and Life Science/Institute of Special Plants, Chongqing University of Arts and Sciences, Yongchuan, Chongqing, 402160, China.; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, 150040, China.
For woody plants, clonal propagation efficiency is largely determined by adventitious root (AR) formation at the bases of stem cuttings. However, our understanding of the molecular mechanisms contributing to AR morphogenesis in trees remains limited, despite the importance of vegetative propagation, currently the most common practice for tree breeding and commercialization. Here, we identified Populus-specific miR476a as a regulator of wound-induced adventitious rooting that acts by orchestrating mitochondrial homeostasis. MiR476a exhibited inducible expression during AR formation and directly targeted several Restorer of Fertility like (RFL) genes encoding mitochondrion-localized pentatricopeptide repeat proteins. Genetic modification of miR476a-RFL expression revealed that miR476a/RFL-mediated dynamic regulation of mitochondrial homeostasis influences AR formation in poplar. Mitochondrial perturbation via exogenous application of a chemical inhibitor indicated that miR476a/RFL-directed AR formation depends on mitochondrial regulation that acts via auxin signaling. Our results thus establish a miRNA-directed mitochondrion-auxin signaling cascade required for AR development, providing insights into the role of mitochondrial regulation in the developmental plasticity of plants.
PMID: 33533479
New Phytol , IF:8.512 , 2021 Feb , V229 (4) : P2206-2222 doi: 10.1111/nph.16978
Apple SUMO E3 ligase MdSIZ1 facilitates SUMOylation of MdARF8 to regulate lateral root formation.
State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, Shandong Agricultural University, Tai-An, Shandong, 271018, China.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture and Rural Affairs, College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.
Post-translational modification of proteins mediated by SIZ1, a small ubiquitin-like modifier (SUMO) E3 ligase, regulates multiple biological processes in plants. However, its role in the regulation of lateral root formation remains unclear. Here, we demonstrate that the apple SUMO E3 ligase MdSIZ1 promotes lateral root formation. Using a yeast-two-hybrid (Y2H) system, the auxin response factor MdARF8 was screened out as a protein-protein interaction partner of the SUMO-conjugating E2 enzyme MdSCE1, indicating that MdARF8 may be a substrate for MdSIZ1. The interaction between MdARF8 and MdSCE1 was confirmed by pull-down, Y2H and Co-immunoprecipitation assays. MdSIZ1 enhanced the conjugating enzyme activity of MdSCE1 to form a MdSCE1-MdSIZ1-MdARF8 complex, thereby facilitating SUMO modification. We identified two arginine substitution mutations at K342 and K380 in MdARF8 that blocked MdSIZ1-mediated SUMOylation, indicating that K342 and K380 are the principal SUMOylation sites of the MdARF8 protein. Moreover, MdARF8 promoted lateral root formation in transgenic apple plants, and the phenotype of reduced lateral roots in the Arabidopsis siz1-2 mutant was restored in siz1-2/MdARF8 complementary plants. Our findings reveal an important role for sumoylation in the regulation of lateral root formation in plants.
PMID: 33006771
New Phytol , IF:8.512 , 2021 Feb , V229 (3) : P1553-1565 doi: 10.1111/nph.16956
Trehalose 6-phosphate promotes seed filling by activating auxin biosynthesis.
Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstr. 3, Stadt Seeland OT Gatersleben, 06466, Germany.; DeepTrait S.A., Dobrzanskiego 3, Lublin, 20-262, Poland.; School of Natural Sciences, University of Tasmania, Sandy Bay, 7001, Australia.; Faculty of Biology, Ludwig Maximilians University of Munich, Grosshaderner Str. 2, Planegg-Martinsried, 82152, Germany.; Max Planck Institute of Molecular Plant Physiology, Am Muhlenberg 1, Potsdam, 14476, Germany.
Plants undergo several developmental transitions during their life cycle. One of these, the differentiation of the young embryo from a meristem-like structure into a highly specialized storage organ, is believed to be controlled by local connections between sugars and hormonal response systems. However, we know little about the regulatory networks underpinning the sugar-hormone interactions in developing seeds. By modulating the trehalose 6-phosphate (T6P) content in growing embryos of garden pea (Pisum sativum), we investigate here the role of this signaling sugar during the seed-filling process. Seeds deficient in T6P are compromised in size and starch production, resembling the wrinkled seeds studied by Gregor Mendel. We show also that T6P exerts these effects by stimulating the biosynthesis of the pivotal plant hormone, auxin. We found that T6P promotes the expression of the auxin biosynthesis gene TRYPTOPHAN AMINOTRANSFERASE RELATED2 (TAR2), and the resulting effect on auxin concentrations is required to mediate the T6P-induced activation of storage processes. Our results suggest that auxin acts downstream of T6P to facilitate seed filling, thereby providing a salient example of how a metabolic signal governs the hormonal control of an integral phase transition in a crop plant.
PMID: 32984971
Curr Opin Plant Biol , IF:8.356 , 2021 Feb , V59 : P101975 doi: 10.1016/j.pbi.2020.10.007
MIXTAs and phytohormones orchestrate cotton fiber development.
Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, 310029 Zhejiang, PR China; National Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, PR China.; Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, 310029 Zhejiang, PR China. Electronic address: cotton@zju.edu.cn.
Cotton is the largest source of natural fiber for textile industry in the world. Cotton fibers are seed trichomes that make cotton unique among plants. Cotton fibers originate from ovule epidermal cells and serve as an excellent model to study the process of cell differentiation in plants. Characterization of factors contributing to fiber development will help to reveal general mechanisms of cell differentiation in plants. Transcription factors (TFs), especially MYB-MIXTA-like (MML) factors, appear to have evolved unique roles in fiber development. In addition, phytohormones including brassinosteroids, jasmonic acid, GA and auxin also play an important role in regulating fiber development. Here, we summarize the mechanisms of MIXTAs and phytohormones orchestrating cotton fiber development. The progress in understanding molecular basis of fiber development will facilitate future genetic engineering and breeding to improve cotton fiber quality and yield.
PMID: 33296746
Plant Biotechnol J , IF:8.154 , 2021 Feb doi: 10.1111/pbi.13567
MiR396-GRF module associates with switchgrass biomass yield and feedstock quality.
College of Grassland Science and technology, China Agricultural University, Beijing, China.; College of Life Sciences, Shandong Normal University, Jinan, Shandong, China.; Beijing Key Laboratory of New Technology in Agricultural Application, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.; Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA.; Key Lab of Grassland Science in Beijing, China Agricultural University, Beijing, China.
Improving plant biomass yield and/or feedstock quality for highly efficient lignocellulose conversion has been the main research focus in genetic modification of switchgrass (Panicum virgatum L.), a dedicated model plant for biofuel production. Here, we proved that overexpression of miR396 (OE-miR396) leads to reduced plant height and lignin content mainly by reducing G-lignin monomer content. We identified nineteen PvGRFs in switchgrass and proved thirteen of them were cleaved by miR396. MiR396-targeted PvGRF1, PvGRF9 and PvGRF3 showed significantly higher expression in stem. By separately overexpressing rPvGRF1, 3 and 9, in which synonymous mutations abolished the miR396 target sites, and suppression of PvGRF1/3/9 activity via PvGRF1/3/9-SRDX overexpression in switchgrass, we confirmed PvGRF1 and PvGRF9 played positive roles in improving plant height and G-lignin content. Overexpression of PvGRF9 was sufficient to complement the defective phenotype of OE-miR396 plants. MiR396-PvGRF9 modulates these traits partly by interfering GA and auxin biosynthesis and signalling transduction and cell wall lignin, glucose and xylan biosynthesis pathways. Moreover, by enzymatic hydrolysis analyses, we found that overexpression of rPvGRF9 significantly enhanced per plant sugar yield. Our results suggest that PvGRF9 can be utilized as a candidate molecular tool in modifying plant biomass yield and feedstock quality.
PMID: 33567151
Cell Rep , IF:8.109 , 2021 Feb , V34 (5) : P108717 doi: 10.1016/j.celrep.2021.108717
Heat shock protein 90 co-chaperone modules fine-tune the antagonistic interaction between salicylic acid and auxin biosynthesis in cassava.
Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Crops, Hainan University, Haikou, Hainan 570228, China.; Key Laboratory of Three Gorges Regional Plant Genetics & Germplasm Enhancement (CTGU)/Biotechnology Research Center, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, Hubei 443002, China.; Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Crops, Hainan University, Haikou, Hainan 570228, China. Electronic address: haitaoshi@hainanu.edu.cn.
Heat shock protein 90 (HSP90) is an important molecular chaperone in plants. However, HSP90-mediated plant immune response remains elusive in cassava. In this study, cassava bacterial blight (CBB) induces the expression of MeHsf8, which directly targets MeHSP90.9 to activate its expression and immune response. Further identification of SHI-related sequence 1 (MeSRS1) and MeWRKY20 as MeHSP90.9 co-chaperones revealed the underlying mechanism of MeHSP90.9-mediated immune response. MeHSP90.9 interacts with MeSRS1 and MeWRKY20 to promote their transcriptional activation of salicylic acid (SA) biosynthetic gene avrPphB Susceptible 3 (MePBS3) and tryptophan metabolic gene N-acetylserotonin O-methyltransferase 2 (MeASMT2), respectively, so as to activate SA biosynthesis but inhibit tryptophan-derived auxin biosynthesis. Notably, genetic experiments confirmed that overexpressing MePBS3 and MeASMT2 could rescue the effects of silencing MeHsf8-MeHSP90.9 on disease resistance. This study highlights the dual regulation of SA and auxin biosynthesis by MeHSP90.9, providing the mechanistic understanding of MeHSP90.9 client partners in plant immunity.
PMID: 33535044
Crit Rev Biotechnol , IF:8.108 , 2021 Feb : P1-25 doi: 10.1080/07388551.2020.1869690
In vitro adventitious roots: a non-disruptive technology for the production of phytoconstituents on the industrial scale.
Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (IHBT), Palampur, India.; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India.; Dietetics and Nutrition Technology, CSIR-Institute of Himalayan Bioresource Technology (IHBT), Palampur, India.; CSIR-Institute of Himalayan Bioresource Technology (IHBT), Palampur, India.
The current trends of consumer-driven demands for natural therapeutics and the availability of evidence-based phytopharmaceuticals from traditional knowledge has once again brought the medicinal plants into forefront of health. In 2019, World Health Organization global report on traditional and complementary medicine has also substantiated the revival of herbal medicine including its convergence with conventional medicine for the management and prevention of diseases. It means these industries need plenty of plant materials to meet the unprecedented demands of herbal formulations. However, it is pertinent to mention here that around 70-80% medicinal plants are sourced from the wild and most of such highly acclaimed plants are listed under Rare, Endangered and Threatened species by IUCN. Additionally, over 30% traditional health formulations are based on underground plant parts, which lead to the uprooting of plants. Overharvesting from limited plant populations, meager conventional cultivation and a rising fondness for natural products exerting enormous pressure on natural habitats. Therefore, the nondestructive means of phytochemical production employing biotechnological tools could be used for sustainable production and consumption patterns. In recent years, a number of reports described the use of adventitious roots induced under in vitro conditions for the extraction of phytochemicals on a sustainable basis. In this article, efforts are made to review recent developments in this area as well as understand the induction mechanisms of adventitious roots, their in vitro cultivation, probable factors that affect the growth and metabolite production, and assess the possibility of industrial scale production to meet the rising demands of natural herbs.
PMID: 33586555
Cold Spring Harb Perspect Biol , IF:7.64 , 2021 Feb doi: 10.1101/cshperspect.a040048
On the Evolutionary Origins of Land Plant Auxin Biology.
School of Biological Science, Monash University, Melbourne, Victoria 3800, Australia.; Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.; Graduate School of Science, Kobe University, Kobe 657-8501, Japan.
Indole-3-acetic acid, that is, auxin, is a molecule found in a broad phylogenetic distribution of organisms, from bacteria to eukaryotes. In the ancestral land plant auxin was co-opted to be the paramount phytohormone mediating tropic responses and acting as a facilitator of developmental decisions throughout the life cycle. The evolutionary origins of land plant auxin biology genes can now be traced with reasonable clarity. Genes encoding the two enzymes of the land plant auxin biosynthetic pathway arose in the ancestral land plant by a combination of horizontal gene transfer from bacteria and possible neofunctionalization following gene duplication. Components of the auxin transcriptional signaling network have their origins in ancestral alga genes, with gene duplication and neofunctionalization of key domains allowing integration of a portion of the preexisting transcriptional network with auxin. Knowledge of the roles of orthologous genes in extant charophycean algae is lacking, but could illuminate the ancestral functions of both auxin and the co-opted transcriptional network.
PMID: 33558368
Cold Spring Harb Perspect Biol , IF:7.64 , 2021 Feb doi: 10.1101/cshperspect.a039941
Auxin-Regulated Lateral Root Organogenesis.
Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
Plant fitness is largely dependent on the root, the underground organ, which, besides its anchoring function, supplies the plant body with water and all nutrients necessary for growth and development. To exploit the soil effectively, roots must constantly integrate environmental signals and react through adjustment of growth and development. Important components of the root management strategy involve a rapid modulation of the root growth kinetics and growth direction, as well as an increase of the root system radius through formation of lateral roots (LRs). At the molecular level, such a fascinating growth and developmental flexibility of root organ requires regulatory networks that guarantee stability of the developmental program but also allows integration of various environmental inputs. The plant hormone auxin is one of the principal endogenous regulators of root system architecture by controlling primary root growth and formation of LR. In this review, we discuss recent progress in understanding molecular networks where auxin is one of the main players shaping the root system and acting as mediator between endogenous cues and environmental factors.
PMID: 33558367
Cold Spring Harb Perspect Biol , IF:7.64 , 2021 Feb , V13 (2) doi: 10.1101/cshperspect.a039974
Auxin and Flower Development: A Blossoming Field.
Dipartimento di Bioscienze, Universita degli Studi di Milano, 20133 Milan, Italy.; Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.
The establishment of the species-specific floral organ body plan involves many coordinated spatiotemporal processes, which include the perception of positional information that specifies floral meristem and floral organ founder cells, coordinated organ outgrowth coupled with the generation and maintenance of inter-organ and inter-whorl boundaries, and the termination of meristem activity. Auxin is integrated within the gene regulatory networks that control these processes and plays instructive roles at the level of tissue-specific biosynthesis and polar transport to generate local maxima, perception, and signaling. Key features of auxin function in several floral contexts include cell nonautonomy, interaction with cytokinin gradients, and the central role of MONOPTEROS and ETTIN to regulate canonical and noncanonical auxin response pathways, respectively. Arabidopsis flowers are not representative of the enormous angiosperm floral diversity; therefore, comparative studies are required to understand how auxin underlies these developmental differences. It will be of great interest to compare the conservation of auxin pathways among flowering plants and to discuss the evolutionary role of auxin in floral development.
PMID: 33355218
Metab Eng , IF:7.263 , 2021 Feb , V64 : P85-94 doi: 10.1016/j.ymben.2021.01.010
Quorum sensing-mediated protein degradation for dynamic metabolic pathway control in Saccharomyces cerevisiae.
State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China.; State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China; State Key Laboratory of Biobased Material and Green Papermaking, School of Bioengineering, Qi Lu University of Technology, Jinan, 250353, PR China.; State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, PR China. Electronic address: houjin@sdu.edu.cn.
Dynamic regulation has been widely applied to optimize metabolic flux distribution. However, compared with prokaryotes, quorum sensing-mediated pathway control is still very limited in Saccharomyces cerevisiae. In this study, we designed quorum sensing-regulated protein degradation circuits for dynamic metabolic pathway control in S. cerevisiae. The synthetic quorum sensing circuits were developed by integration of a plant hormone cytokinin system with the endogenous yeast Ypd1-Skn7 signal transduction pathway and the positive feedback circuits were optimized by promoter engineering. We then constructed an auxin-inducible protein degradation system and used quorum sensing circuits to regulate auxin synthesis to achieve dynamic control of protein degradation. As a demonstration, the circuits were applied to control Erg9 degradation to produce alpha-farnesene and the titer of alpha-farnesene increased by 80%. The population-regulated protein degradation system developed here extends dynamic regulation to the protein level in S. cerevisiae and is a promising approach for metabolic pathway control.
PMID: 33545357
Plant Physiol , IF:6.902 , 2021 Feb , V185 (1) : P256-273 doi: 10.1093/plphys/kiaa023
SAUR proteins and PP2C.D phosphatases regulate H+-ATPases and K+ channels to control stomatal movements.
Department of Plant and Microbial Biology, University of Minnesota, St Paul, Minnesota 55108, USA.; Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, UK.; Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280, USA.
Activation of plasma membrane (PM) H+-ATPase activity is crucial in guard cells to promote light-stimulated stomatal opening, and in growing organs to promote cell expansion. In growing organs, SMALL AUXIN UP RNA (SAUR) proteins inhibit the PP2C.D2, PP2C.D5, and PP2C.D6 (PP2C.D2/5/6) phosphatases, thereby preventing dephosphorylation of the penultimate phosphothreonine of PM H+-ATPases and trapping them in the activated state to promote cell expansion. To elucidate whether SAUR-PP2C.D regulatory modules also affect reversible cell expansion, we examined stomatal apertures and conductances of Arabidopsis thaliana plants with altered SAUR or PP2C.D activity. Here, we report that the pp2c.d2/5/6 triple knockout mutant plants and plant lines overexpressing SAUR fusion proteins exhibit enhanced stomatal apertures and conductances. Reciprocally, saur56 saur60 double mutants, lacking two SAUR genes normally expressed in guard cells, displayed reduced apertures and conductances, as did plants overexpressing PP2C.D5. Although altered PM H+-ATPase activity contributes to these stomatal phenotypes, voltage clamp analysis showed significant changes also in K+ channel gating in lines with altered SAUR and PP2C.D function. Together, our findings demonstrate that SAUR and PP2C.D proteins act antagonistically to facilitate stomatal movements through a concerted targeting of both ATP-dependent H+ pumping and channel-mediated K+ transport.
PMID: 33631805
Plant Physiol , IF:6.902 , 2021 Feb , V185 (1) : P120-136 doi: 10.1093/plphys/kiaa002
Long chain acyl CoA synthetase 4 catalyzes the first step in peroxisomal indole-3-butyric acid to IAA conversion.
Department of Biology, University of Missouri - St Louis, St Louis, Missouri 63121, USA.
Indole-3-butyric acid (IBA) is an endogenous storage auxin important for maintaining appropriate indole-3-acetic acid (IAA) levels, thereby influencingprimary root elongation and lateral root development. IBA is metabolized into free IAA in peroxisomes in a multistep process similar to fatty acid beta-oxidation. We identified LONG CHAIN ACYL-COA SYNTHETASE 4 (LACS4) in a screen for enhanced IBA resistance in primary root elongation in Arabidopsis thaliana. LACSs activate substrates by catalyzing the addition of CoA, the necessary first step for fatty acids to participate in beta-oxidation or other metabolic pathways. Here, we describe the novel role of LACS4 in hormone metabolism and postulate that LACS4 catalyzes the addition of CoA onto IBA, the first step in its beta-oxidation. lacs4 is resistant to the effects of IBA in primary root elongation and dark-grown hypocotyl elongation, and has reduced lateral root density. lacs6 also is resistant to IBA, although both lacs4 and lacs6 remain sensitive to IAA in primary root elongation, demonstrating that auxin responses are intact. LACS4 has in vitro enzymatic activity on IBA, but not IAA or IAA conjugates, and disruption of LACS4 activity reduces the amount of IBA-derived IAA in planta. We conclude that, in addition to activity on fatty acids, LACS4 and LACS6 also catalyze the addition of CoA onto IBA, the first step in IBA metabolism and a necessary step in generating IBA-derived IAA.
PMID: 33631795
Plant Physiol , IF:6.902 , 2021 Feb doi: 10.1093/plphys/kiab087
A Role for Auxin in Triggering Lamina Outgrowth of Unifacial Leaves.
Department of Biological Sciences, Graduate school of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
A common morphological feature of typical angiosperms is the patterning of lateral organs along primary axes of asymmetry-a proximodistal, a mediolateral, and an adaxial-abaxial axis. Angiosperm leaves usually have distinct adaxial-abaxial identity, which is required for the development of a flat shape. By contrast, many unifacial leaves, consisting of only the abaxial side, show a flattened morphology. This implicates a unique mechanism that allows leaf flattening independent of adaxial-abaxial identity. In this study, we report a role for auxin in outgrowth of unifacial leaves. In two closely related unifacial-leaved species of Juncaceae, Juncus prismatocarpus with flattened leaves, and J. wallichianus with transversally radialized leaves, the auxin-responsive gene GLYCOSIDE HYDROLASE3 (GH3) displayed spatially different expression patterns within leaf primordia. Treatment of J. prismatocarpus seedlings with exogenous auxin or auxin transport inhibitors, which disturb endogenous auxin distribution, eliminated leaf flatness, resulting in a transversally radialized morphology. These treatments did not affect the radialized morphology of leaves of J. wallichianus. Moreover, elimination of leaf flatness by these treatments accompanied dysregulated expression of genetic factors needed to specify the leaf central-marginal polarity in J. prismatocarpus. The findings imply that lamina outgrowth of unifacial leaves relies on proper placement of auxin, which might induce initial leaf flattening and subsequently act to specify leaf polarity, promoting further flattening growth of leaves.
PMID: 33620494
Plant Physiol , IF:6.902 , 2021 Feb doi: 10.1093/plphys/kiab006
Time-course observation of the reconstruction of stem cell niche in the intact root.
College of Life Sciences, College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China.
The stem cell niche (SCN) is critical in maintaining continuous postembryonic growth of the plant root. During their growth in soil, plant roots are often challenged by various biotic or abiotic stresses, resulting in damage to the SCN. This can be repaired by the reconstruction of a functional SCN. Previous studies examining the SCN's reconstruction often introduce physical damage including laser ablation or surgical excision. In this study, we performed a time-course observation of the SCN reconstruction in pWOX5:icals3m roots, an inducible system that causes non-invasive SCN differentiation upon induction of estradiol on Arabidopsis (Arabidopsis thaliana) root. We found a stage-dependent reconstruction of SCN in pWOX5:icals3m roots, with division-driven anatomic reorganization in the early stage of the SCN recovery, and cell fate specification of new SCN in later stages. During the recovery of the SCN, the local accumulation of auxin was coincident with the cell division pattern, exhibiting a spatial shift in the root tip. In the early stage, division mostly occurred in the neighboring stele to the SCN position, while division in endodermal layers seemed to contribute more in the later stages, when the SCN was specified. The precise re-positioning of SCN seemed to be determined by mutual antagonism between auxin and cytokinin, a conserved mechanism that also regulates damage-induced root regeneration. Our results thus provide time-course information about the reconstruction of SCN in intact Arabidopsis roots, which highlights the stage-dependent re-patterning in response to differentiated quiescent center.
PMID: 33599750
Plant Physiol , IF:6.902 , 2021 Feb doi: 10.1093/plphys/kiab075
Narrow Leaf21, Encoding Ribosomal Protein RPS3A, Controls Leaf Development in Rice.
National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.; Shandong Rice Research Institute, Jinan 250100, China.
Leaf morphology influences photosynthesis, transpiration and ultimately crop yield. However, the molecular mechanism of leaf development is still not fully understood. Here, we identified and characterized the narrow leaf21 (nal21) mutant in rice (Oryza sativa), showing a significant reduction in leaf width, leaf length and plant height, and increased tiller number. Microscopic observation revealed defects in the vascular system and reduced epidermal cell size and number in the nal21 leaf blade. Map-based cloning revealed that NAL21 encodes a ribosomal small subunit protein RPS3A. Ribosome-targeting antibiotics resistance assay and ribosome profiling showed a significant reduction in the free 40S ribosome subunit in the nal21 mutant. The nal21 mutant showed aberrant auxin responses in which multiple auxin response factors (ARFs) harboring upstream open reading frames (uORFs) in their 5'-untranslated region (5'-UTR) were repressed at the translational level. The WUSCHEL-related homeobox 3A (OsWOX3A) gene, a key transcription factor involved in leaf blade lateral outgrowth, is also under the translational regulation by RPS3A. Transformation with modified OsARF11, OsARF16 and OsWOX3A genomic DNA lacking uORFs rescued the narrow leaf phenotype of nal21 to a better extent than transformation with their native genomic DNA, implying that RPS3A could regulate translation of ARFs and WOX3A through uORFs. Our results demonstrate that proper translational regulation of key factors involved in leaf development is essential to maintain normal leaf morphology.
PMID: 33591317
Plant Physiol , IF:6.902 , 2021 Feb doi: 10.1093/plphys/kiab059
OsGRETCHENHAGEN3-2 modulates rice seed storability via accumulation of abscisic acid and protective substances.
National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Seed storability largely determines the vigor of seeds during storage and is significant in agriculture and ecology. However, the underlying genetic basis remains unclear. In the present study, we report the cloning and characterization of the rice (Oryza sativa) indole-3-acetic acid (IAA)-amido synthetase gene GRETCHEN HAGEN3-2 (OsGH3-2) associated with seed storability. OsGH3-2 was identified by performing a genome-wide association study in rice germplasms with linkage mapping in chromosome substitution segment lines, contributing to the wide variation of seed viability in the populations after long periods of storage and artificial ageing. OsGH3-2 was dominantly expressed in the developing seeds and catalyzed IAA conjugation to amino acids, forming inactive auxin. Transgenic overexpression, knockout and knockdown experiments demonstrated that OsGH3-2 affected seed storability by regulating the accumulation level of abscisic acid. Overexpression of OsGH3-2 significantly decreased seed storability, while knockout or knockdown of the gene enhanced seed storability compared with the wild type. OsGH3-2 acted as a negative regulator of seed storability by modulating many genes related to the abscisic acid pathway and probably subsequently late embryogenesis-abundant proteins at the transcription level. These findings shed light on the molecular mechanisms underlying seed storability and will facilitate the improvement of seed vigor by genomic breeding and gene-editing approaches in rice.
PMID: 33570603
Sci Total Environ , IF:6.551 , 2021 Feb , V757 : P143994 doi: 10.1016/j.scitotenv.2020.143994
Adaptive roots of mangrove Avicennia marina: Structure and gene expressions analyses of pneumatophores.
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361102, China.; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361102, China; Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA.; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystem, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361102, China; Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA. Electronic address: liqq@xmu.edu.cn.
The Avicennia marina is a mangrove species widely distributed throughout the tropical and subtropical intertidal wetlands. To adapt to adverse tidal waves and hypoxia environments, A. marina has evolved a sophisticated root system to better secure itself on the muddy soil with downward-grown anchor roots and upward-grown aerial roots, called pneumatophores. However, the process behind the development of a negative-gravitropic pneumatophore is not understood. Paraffin sections reveal anatomical differences among the shoots, anchor roots, and gas exchanging pneumatophores, clearly reflecting their functional diversions. The pneumatophore, in particular, contains abundant aerenchyma tissues and a thin cap structure at the tip. Transcriptomic analyses of both anchor roots and pneumatophores were performed to elucidate gene expression dynamics during the formation of pneumatophores. The results show that the plant hormone auxin regulates multiple different root initiations. The auxin related gene IAA19 plays a key role in pneumatophore development while the interaction of ethylene and abscisic acid is important for aerenchyma formation. Moreover, the molecular mechanisms behind pneumatophore anti-gravitropic growth may be regulated by the reduced strength of the statolith formation signaling pathway. These results shed light on the mechanistic understanding of pneumatophore formation in mangrove plants.
PMID: 33316524
Plant Cell Environ , IF:6.362 , 2021 Feb doi: 10.1111/pce.14036
Abscisic acid mediates barley rhizosheath formation under mild soil drying by promoting root hair growth and auxin response.
Institute of Oceanography, Minjiang University, Fuzhou, China.; Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, China.; College of Agriculture, Yangzhou University, Yangzhou, China.; The Lancaster Environment Centre, Lancaster University, Lancaster, UK.
Soil drying enhances root ABA accumulation and rhizosheath formation, but whether ABA mediates rhizosheath formation is unclear. Here, we used the ABA-deficient mutant Az34 to investigate molecular and morphological changes by which ABA could affect rhizosheath formation. Mild soil drying with intermittent watering increased rhizosheath formation by promoting root and root hair elongation. Attenuated root ABA accumulation in Az34 barley constrained the promotion of root length and root hair length by drying soil, such that Az34 had a smaller rhizosheath. Pharmacological experiments of adding fluridone (an ABA biosynthesis inhibitor) and ABA to drying soil restricted and enhanced rhizosheath formation respectively in Az34 and wild-type Steptoe barley. RNA sequencing suggested that ABA accumulation mediates auxin synthesis and responses, root and root hair elongation in drying soil. In addition, adding indole-3-acetic acid (IAA) to drying soil increased rhizosheath formation by promoting root and root hair elongation in Steptoe and Az34 barley. Together, these results show that ABA accumulation induced by mild soil drying enhance barley rhizosheath formation, which may be achieved through promoting auxin response. This article is protected by copyright. All rights reserved.
PMID: 33629760
Plant Cell Environ , IF:6.362 , 2021 Feb doi: 10.1111/pce.14031
A chloroplast heat shock protein modulates growth and abiotic stress response in creeping bentgrass.
College of Agronomy, Hebei Agricultural University/State Key Laboratory of North China Crop Improvement and Regulation//Key Laboratory of Crop Growth Regulation of Hebei Province, Baoding, Hebei, China.; Human Resource Department, Hebei Agricultural University, Baoding, Hebei, China.; Department of Genetics and Biochemistry, Clemson University, 110 Biosystems Research Complex, Clemson, South Carolina, USA.
Small heat shock proteins (sHSPs), a family of the ubiquitous stress proteins in plants acting as molecular chaperones to protect other proteins from stress-induced damage, have been implicated in plant growth and development as well as plant response to environmental stress, especially heat stress. In this study, a chloroplast-localized sHSP, AsHSP26.8 was overexpressed in creeping bentgrass (Agrostis stolonifera L.) to study its role in regulating plant growth and stress response. Transgenic (TG) creeping bentgrass plants displayed arrested root development, slow growth rate, twisted leaf blades and are more susceptible to heat and salt, but less sensitive to drought stress compared to wild type (WT) controls. RNA-seq analysis revealed that AsHSP26.8 modulated the expression of genes in auxin signaling, and stress-related genes such as those encoding HSPs, heat shock factors, and other transcription factors. Our results provide new evidence demonstrating that AsHSP26.8 negatively regulates plant growth, development, and plays differential roles in plant response to a plethora of diverse abiotic stresses. This article is protected by copyright. All rights reserved.
PMID: 33583055
Plant Cell Environ , IF:6.362 , 2021 Feb doi: 10.1111/pce.14029
INDITTO2 transposon conveys auxin-mediated DRO1 transcription for rice drought avoidance.
College of Plant Protection, Yunnan Agricultural University, Kunming, China.; State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China.; Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, China.; Shanxi Agricultural University/Shanxi Academy of Agricultural Sciences. The Industrial Crop Institute, Fenyang, China.; State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.; CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, China.; Key Laboratory of Economic Plants and Biotechnology, Yunnan Key Laboratory for Research and Development of Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.; International Agriculture Research Institute, Yunnan Academy of Agricultural Sciences, Beijing Rd.2238, Kunming, China.; Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria.
Transposable elements exist widely throughout plant genomes and play important roles in plant evolution. Auxin is an important regulator that is traditionally associated with root development and drought stress adaptation. The DEEPER ROOTING 1 (DRO1) gene is a key component of rice drought avoidance. Here, we identified a transposon that acts as an autonomous auxin-responsive promoter and its presence at specific genome positions conveys physiological adaptations related to drought avoidance. Rice varieties with high and auxin-mediated transcription of DRO1 in the root tip show deeper and longer root phenotypes and are thus better adapted to drought. The INDITTO2 transposon contains an auxin response element and displays auxin-responsive promoter activity; it is thus able to convey auxin regulation of transcription to genes in its proximity. In the rice Acuce, which displays DRO1-mediated drought adaptation, the INDITTO2 transposon was found to be inserted at the promoter region of the DRO1 locus. Transgenesis-based insertion of the INDITTO2 transposon into the DRO1 promoter of the non-adapted rice variety Nipponbare was sufficient to promote its drought avoidance. Our data identify an example of how transposons can act as promoters and convey hormonal regulation to nearby loci, improving plant fitness in response to different abiotic stresses. This article is protected by copyright. All rights reserved.
PMID: 33576018
Plant Cell Environ , IF:6.362 , 2021 Feb doi: 10.1111/pce.14021
Volatile compounds from beneficial rhizobacteria Bacillus spp. promote periodic lateral root development in Arabidopsis.
Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China.; State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, China.; Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
Lateral root formation is coordinated by both endogenous and external factors. As biotic factors, plant growth-promoting rhizobacteria can affect lateral root formation, while the regulation mechanism is unclear. In this study, by applying various marker lines, we found that volatile compounds (VCs) from Bacillus amyloliquefaciens SQR9 induced higher frequency of DR5 oscillation and prebranch site formation, accelerated the development and emergence of the lateral root primordia and thus promoted lateral root development in Arabidopsis. We demonstrated a critical role of auxin on B. amyloliquefaciens VCs-induced lateral root formation via respective mutants and pharmacological experiments. Our results showed that auxin biosynthesis, polar transport and signalling pathway are involved in B. amyloliquefaciens VCs-induced lateral roots formation. We further showed that acetoin, a major component of B. amyloliquefaciens VCs, is less active in promoting root development compared to VC blends from B. amyloliquefaciens, indicating the presence of yet uncharacterized/unknown VCs might contribute to B. amyloliquefaciens effect on lateral root formation. In summary, our study revealed an auxin-dependent mechanism of B. amyloliquefaciens VCs in regulating lateral root branching in a non-contact manner, and further efforts will explore useful VCs to promote plant root development.
PMID: 33548150
Plant Cell Environ , IF:6.362 , 2021 Feb doi: 10.1111/pce.14020
AIR12 confers cold tolerance through regulation of the CBF cold response pathway and ascorbate homeostasis.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Engineering Research Center for Grassland Science, College of Life Sciences, South China Agricultural University, Guangzhou, China.; College of Grassland Science, Nanjing Agricultural University, Nanjing, China.
Auxin induced in root culture (AIR12) is a single gene in Arabidopsis and codes for a mono-heme cytochrome b, but it is unknown whether plant AIR12 is involved in abiotic stress responses. MfAIR12 was identified from Medicago falcata that is legume germplasm with great cold tolerance. Transcript levels of MfAIR12 and its homolog MtAIR12 from Medicago truncatula was induced under low temperature. Overexpression of MfAIR12 led to the accumulation of H2 O2 in apoplast and enhanced cold tolerance, which was blocked by H2 O2 scavengers, indicating that the increased cold tolerance was dependent upon the accumulated H2 O2 . In addition, declined cold tolerance was observed in Arabidopsis mutant air12, which could be restored by expressing MfAIR12. Compared to the wild type, higher levels of ascorbic acid and ascorbate redox state, as well as transcripts of the C repeat/dehydration responsive element-binding factor (CBF) transcription factors and their downstream cold-responsive genes, were observed in MfAIR12 transgenic lines, but lower levels of those in air12 mutant. It is suggested AIR12 confers cold tolerance as a result of the altered H2 O2 in the apoplast that is signaling in the regulation of CBF cold response pathway and ascorbate homeostasis.
PMID: 33547695
PLoS Pathog , IF:6.218 , 2021 Feb , V17 (2) : Pe1009242 doi: 10.1371/journal.ppat.1009242
Current understanding of the interplays between host hormones and plant viral infections.
State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.; Vector-borne Virus Research Center, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China.
Phytohormones mediate plant development and responses to stresses caused by biotic agents or abiotic factors. The functions of phytohormones in responses to viral infection have been intensively studied, and the emerging picture of complex mechanisms provides insights into the roles that phytohormones play in defense regulation as a whole. These hormone signaling pathways are not simple linear or isolated cascades, but exhibit crosstalk with each other. Here, we summarized the current understanding of recent advances for the classical defense hormones salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) and also the roles of abscisic acid (ABA), auxin, gibberellic acid (GA), cytokinins (CKs), and brassinosteroids (BRs) in modulating plant-virus interactions.
PMID: 33630970
Plant J , IF:6.141 , 2021 Feb doi: 10.1111/tpj.15208
Cell-Type Action Specificity of Auxin on Arabidopsis Root Growth.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China.; School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, 69978, Israel.
The plant hormone auxin plays a critical role in root growth and development; however, the contributions or specific roles of cell-type auxin signals in root growth and development is not well understood. Here, we mapped tissue and cell types that are important for auxin-mediated root growth and development by manipulating the local response and synthesis of auxin. Repressing auxin signaling in the epidermis, cortex, endodermis, pericycle, or stele strongly inhibited root growth, with the largest effect observed in the endodermis. Enhancing auxin signaling in the epidermis, cortex, endodermis, pericycle, or stele also caused reduced root growth, albeit to a lesser extent. Moreover, we established that root growth was inhibited by enhancement of auxin synthesis in specific cell types of the epidermis, cortex and endodermis, whereas increased auxin synthesis in the pericycle and stele had only minor effects on root growth. Our study thus establishes an association between cellular identity and cell type-specific auxin signaling that guides root growth and development.
PMID: 33609310
Plant J , IF:6.141 , 2021 Feb doi: 10.1111/tpj.15195
Comparative transcriptome profiling identifies maize line specificity of fungal effectors in the maize-Ustilago maydis interaction.
University of Cologne, CEPLAS, Institute for Plant Sciences, Cologne, Germany.; IMPRS, Max Planck Institute for Plant Breeding Research, Cologne, Germany.; Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt a. M, Germany.; Institute of Ecology, Evolution and Diversity, Goethe University, Frankfurt, Frankfurt a. M, Germany.
The biotrophic pathogen Ustilago maydis causes smut disease on maize (Zea mays) and induces the formation of tumours on all aerial parts of the plant. Unlike in other biotrophic interactions, no gene-for-gene interactions have been identified in the maize-U. maydis pathosystem. Thus, maize resistance to U. maydis is considered a polygenic, quantitative trait. Here, we study the molecular mechanisms of quantitative disease resistance (QDR) in maize, and how U. maydis interferes with its components. Based on quantitative scoring of disease symptoms in 26 maize lines, we performed an RNA-Seq analysis of six U. maydis-infected maize lines of highly distinct resistance levels. The different maize lines showed specific responses of diverse cellular processes to U. maydis infection. For U. maydis, our analysis identified 406 genes being differentially expressed between maize lines, of which 102 encode predicted effector proteins. Based on this analysis, we generated U. maydis CRISPR/Cas9 knockout mutants for selected candidate effector sets. Infections of different maize lines with the fungal mutants and subsequent RNA-sequencing identified effectors with quantitative, maize-line-specific virulence functions, and revealed auxin-related processes as a possible target for one of them. Thus, we show that both transcriptional activity and virulence function of fungal effector genes are modified according to the infected maize line, providing insights into the molecular mechanisms underlying QDR in the maize-U. maydis interaction.
PMID: 33570802
Plant J , IF:6.141 , 2021 Feb doi: 10.1111/tpj.15184
Plant stem cell research is uncovering the secrets of longevity and persistent growth.
Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan.; Department of Biology, Faculty of Science, Niigata University, Niigata, 950-2181, Japan.; National Institute for Basic Biology, Okazaki, 444-8585, Japan.; Department of Basic Biology, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, 444-8585, Japan.; Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.; Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan.; Howard Hughes Medical Institute, Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, USA.; Institute of Transformative Biomolecules (WPI-ITbM), Nagoya University, Nagoya, 464-8601, Japan.; Department of Biology, Faculty of Science, Kyushu University, Fukuoka, 819-0395, Japan.; Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.; Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Toba, 517-0004, Japan.; Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601, Japan.
Plant stem cells have several extraordinary features: they are generated de novo during development and regeneration, maintain their pluripotency, and produce another stem cell niche in an orderly manner. This enables plants to survive for an extended period and to continuously make new organs, representing a clear difference in their developmental program from animals. To uncover regulatory principles governing plant stem cell characteristics, our research project 'Principles of pluripotent stem cells underlying plant vitality' was launched in 2017, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Japanese government. Through a collaboration involving 28 research groups, we aim to identify key factors that trigger epigenetic reprogramming and global changes in gene networks, and thereby contribute to stem cell generation. Pluripotent stem cells in the shoot apical meristem are controlled by cytokinin and auxin, which also play a crucial role in terminating stem cell activity in the floral meristem; therefore, we are focusing on biosynthesis, metabolism, transport, perception and signaling of these hormones. Besides, we are uncovering the mechanisms of asymmetric cell division, and of stem cell death and replenishment under DNA stress, which will illuminate plant-specific features in preserving stemness. Our technology support groups expand single-cell omics to describe stem cell behavior in a spatiotemporal context, and provide correlative light and electron microscopic technology to enable live imaging of cell and subcellular dynamics at high spatiotemporal resolution. In this perspective, we discuss future directions of our ongoing projects and related research fields.
PMID: 33533118
Plant J , IF:6.141 , 2021 Feb , V105 (4) : P1053-1071 doi: 10.1111/tpj.15086
The AGCVIII kinase Dw2 modulates cell proliferation, endomembrane trafficking, and MLG/xylan cell wall localization in elongating stem internodes of Sorghum bicolor.
Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas, 77843, USA.; Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA.; Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan, 48824, USA.; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, Michigan, 48824, USA.; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, 48824, USA.
Stems of bioenergy sorghum (Sorghum bicolor L. Moench.), a drought-tolerant C4 grass, contain up to 50 nodes and internodes of varying length that span 4-5 m and account for approximately 84% of harvested biomass. Stem internode growth impacts plant height and biomass accumulation and is regulated by brassinosteroid signaling, auxin transport, and gibberellin biosynthesis. In addition, an AGCVIII kinase (Dw2) regulates sorghum stem internode growth, but the underlying mechanism and signaling network are unknown. Here we provide evidence that mutation of Dw2 reduces cell proliferation in internode intercalary meristems, inhibits endocytosis, and alters the distribution of heteroxylan and mixed linkage glucan in cell walls. Phosphoproteomic analysis showed that Dw2 signaling influences the phosphorylation of proteins involved in lipid signaling (PLDdelta), endomembrane trafficking, hormone, light, and receptor signaling, and photosynthesis. Together, our results show that Dw2 modulates endomembrane function and cell division during sorghum internode growth, providing insight into the regulation of monocot stem development.
PMID: 33211340
Plant J , IF:6.141 , 2021 Feb , V105 (3) : P668-677 doi: 10.1111/tpj.15062
Overexpression of the ribosomal S30 subunit leads to indole-3-carbinol tolerance in Arabidopsis thaliana.
School of Plant Sciences and Food Security, Tel Aviv University, Ramat Aviv, 69978, Israel.; The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, 8499000, Israel.
Indole-3-carbinol (I3C), a hydrolysis product of indole-3-methylglucosinolate, is toxic to herbivorous insects and pathogens. In mammals, I3C is extensively studied for its properties in cancer prevention and treatment. Produced in Brassicaceae, I3C reversibly inhibits root elongation in a concentration-dependent manner. This inhibition is partially explained by the antagonistic action of I3C on auxin signaling through TIR1. To further elucidate the mode of action of I3C in plants, we have identified and characterized a novel Arabidopsis mutant tolerant to I3C, ICT1. This mutant was identified following screening of the Full-length cDNA Over-eXpression library (FOX) seed collection for root growth in the presence of exogenous I3C. ICT1 carries the AT2G19750 gene, which encodes an S30 ribosomal protein. Overexpression, but not knockout, of the S30 gene causes tolerance to I3C. The tolerance is specific to I3C, since ICT1 did not exhibit pronounced tolerance to other indole or benzoxazinoid molecules tested. ICT1 maintains I3C-induced antagonism of auxin signaling, indicating that the tolerance is due to an auxin-independent mechanism. Transcript profiling experiments revealed that ICT1 is transcriptionally primed to respond to I3C treatment.
PMID: 33128319
Anal Chim Acta , IF:5.977 , 2021 Feb , V1145 : P103-113 doi: 10.1016/j.aca.2020.11.008
Polydopamine/graphene/MnO2 composite-based electrochemical sensor for in situ determination of free tryptophan in plants.
Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin Key Laboratory of Drug Targeting and Bioimaging, School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin, 300384, PR China.; Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Tianjin Key Laboratory of Drug Targeting and Bioimaging, School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin, 300384, PR China. Electronic address: hongjili@yeah.net.; Tianjin Key Laboratory of Film Electronic and Communication Devices, Engineering Research Center of Optoelectronic Devices & Communication Technology (Ministry of Education), School of Electrical and Electronic Engineering, Tianjin University of Technology, Tianjin, 300384, PR China. Electronic address: limingji@163.com.; Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China.; College of Electronic Engineering, South China Agricultural University, Guangzhou, 510642, PR China.; Tianjin Key Laboratory of Film Electronic and Communication Devices, Engineering Research Center of Optoelectronic Devices & Communication Technology (Ministry of Education), School of Electrical and Electronic Engineering, Tianjin University of Technology, Tianjin, 300384, PR China.
The in vivo detection of small active molecules in plant tissues is essential for the development of precision agriculture. Tryptophan (Trp) is an important precursor material for auxin biosynthesis in plants, and the detection of Trp levels in plants is critical for regulating the plant growth process. In this study, an electrochemical plant sensor was fabricated by electrochemically depositing a polydopamine (PDA)/reduced graphene oxide (RGO)-MnO2 nanocomposite onto a glassy carbon electrode (GCE). PDA/RGO-MnO2/GCE exhibited high electrocatalytic activity for the oxidation of Trp owing to the combined selectivity of PDA and catalytic activity of RGO-MnO2. To address the pH variability of plants, a reliable Trp detection program was proposed for selecting an appropriate quantitative detection model for the pH of the plant or plant tissue of interest. Therefore, a series of linear regression curves was constructed in the pH range of 4.0-7.0 using the PDA/RGO-MnO2/GCE-based sensor. In this pH range, the linear detection range of Trp was 1-300 muM, the sensitivity was 0.39-1.66 muA muM(-1), and the detection limit was 0.22-0.39 muM. Moreover, the practical applicability of the PDA/RGO-MnO2/GCE-based sensor was successfully demonstrated by determining Trp in tomato fruit and juice. This sensor stably and reliably detected Trp levels in tomatoes in vitro and in vivo, demonstrating the feasibility of this research strategy for the development of electrochemical sensors for measurements in various plant tissues.
PMID: 33453871
J Exp Bot , IF:5.908 , 2021 Feb doi: 10.1093/jxb/erab089
Auxin and Gibberellin signaling cross-talk promotes hypocotyl xylem expansion and cambium homeostasis.
ZMBP- Center for Plant Molecular Biology, University of Tubingen, Auf der Morgenstelle, Tubingen, Germany.; Max Planck Institute for Developmental Biology, Max-Planck-Ring, Tubingen, Germany.
During secondary growth, the thickening of plant organs, wood (xylem) and bast (phloem) are continuously produced by the vascular cambium. In Arabidopsis hypocotyl and root, we can distinguish two phases of secondary growth based on cell morphology and production rate. The first phase, in which xylem and phloem are equally produced, precedes the xylem expansion phase in which xylem formation is enhanced and xylem fibers differentiate. It is known that Gibberellins (GA) trigger this developmental transition via the degradation of DELLA proteins and that the cambium master regulator BREVIPEDICELLUS/KNAT1 (BP/KNAT1) and the receptor like kinases ERECTA and ERL1 regulate this process downstream of GA. However, our understandings on the regulatory network underlying GA-mediated secondary growth, are still limited. Here, we demonstrate that DELLA-mediated xylem expansion is mainly achieved through RGA and GAI and that RGA and GAI promote cambium senescence. We further show that AUXIN RESPONSE FACTOR (ARF6) and ARF8, which physically interact with DELLAs, specifically repress phloem proliferation and induce cambium senescence during the xylem expansion phase. Moreover, the inactivation of BP in arf6 arf8 background revealed an essential role for ARF6 and ARF8 in cambium establishment and maintenance. Overall, our results shed light on a pivotal hormone cross-talk between GA and auxin in the context of plant secondary growth.
PMID: 33619529
J Exp Bot , IF:5.908 , 2021 Feb doi: 10.1093/jxb/erab056
Arabidopsis WXR1/3 regulate transitory starch metabolism in young seedlingscorresponding to circadian rhythm.
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China.; Shandong Provincial Key Laboratory of Biophysics, College of Physical and Electronic information, Dezhou University, Dezhou China.; Center ofCrop Science, College of Agronomy, Qingdao Agriculture University, Qingdao China.
Transitory starch is the portion of starch synthesized during the day in the chloroplast and usually used up for plant growth during the night.Here we found altered metabolism of transitory starch in the wxr1/wxr3(weak auxinresponse)mutants of Arabidopsis.WXR1/WXR3 are previously reported to regulate root growth of young seedling and affect auxin response mediated by auxin polar transport in Arabidopsis. In this study thewxr1/wxr3 mutants accumulated transitory starch in the cotyledon, young leaf and hypocotyl at end of night (EON). The expression of WXR1/WXR3follows an obvious circadian rhythm. Grafting experiments proved that the WXRs in root were necessary for proper starch metabolism and plant growth.Other findings include that photosynthesis was inhibited, and the transcription level of DIN1 /DIN6 (Dark-Inducible 1/6) was reducedin wxr1/wxr3. Meanwhile, the mutants showed a defect in ionic equilibrium of Na+ and K+, consistent with our bioinformatics data that genes related to ionic equilibrium were mis-regulated in wxr1. The loss of WXR1 function also resulted in abnormal trafficking of the membrane lipids and proteins. In conclusion, this study reveals that the plastid protein WXR1/WXR3 play important roles in promoting transitory starch degradation for plant growth during the night, possibly through regulating ionic equilibrium in the root.
PMID: 33571997
J Exp Bot , IF:5.908 , 2021 Feb doi: 10.1093/jxb/erab046
Axillary bud outgrowth in rose is controlled by sugar metabolic and signalling pathways.
IRHS-UMR1345, Universite d'Angers, INRAE, Institut Agro, SFR 4207 QuaSaV, Beaucouze, France.; College of Agronomy, Qingdao Agricultural University, Qingdao, China.; Institut de Biologie Moleculaire des Plantes, Centre National de la Recherche Scientifique, Unite Propre de Recherche, Conventionne avec l'Universite de Strasbourg, Strasbourg, France.; The University of Queensland, School of Biological Sciences, St. Lucia, Australia.; Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, Universite Paris-Sud, Universite d'Evry, Universite Paris-Saclay, Batiment 630, Plateau de Moulon, Gif sur Yvette, France.; Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Universite Paris-Saclay, Versailles, France.
Shoot branching is a pivotal process during plant growth and development, antagonistically orchestrated by auxin and sugars. By contrast to extensive investigations on hormonal regulatory networks, our current knowledge on the role of sugar signalling pathways in bud outgrowth is still scarce. Based on a stepwise and comprehensive strategy, we investigated the role of glycolysis/the tricarboxylic acid (TCA) cycle and the oxidative pentose phosphate pathway (OPPP) in the control of bud outgrowth. We demonstrated that these two pathways are necessary for bud outgrowth promotion upon plant decapitation and in response to sugar availability. They are also targets of the antagonistic crosstalk between auxin and sugar availability. These two pathways act synergistically to downregulate the expression of BRC1, a conserved inhibitor of shoot branching. Using Rosa calluses stably transformed with GFP-fused promoter sequences of RhBRC1 (pRhBRC1), glycolysis/TCA-cycle and the OPPP were found to repress the transcriptional activity of pRhBRC1 cooperatively. Glycolysis/TCA-cycle- and OPPP-dependent regulations involve the -1973bp/-1611bp and -1206bp/-709bp regions of pRhBRC1, respectively. Taken together, our findings indicate that glycolysis/the tricarboxylic acid cycle and the OPPP are integrative parts of shoot branching control and can link endogenous factors to the developmental program of bud outgrowth, more likely through two distinct mechanisms.
PMID: 33543244
J Exp Bot , IF:5.908 , 2021 Feb , V72 (4) : P1151-1165 doi: 10.1093/jxb/eraa501
Auxin biosynthesis and cellular efflux act together to regulate leaf vein patterning.
Institute of Biology II, Albert-Ludwigs-University of Freiburg, Schanzlestrasse 1, D-79104 Freiburg, Germany.; Physics of Biological Organization, Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, D-37077 Gottingen, Germany.; Institute of General Electrical Engineering, University of Rostock, Albert-Einstein-Str. 2, D-18059 Rostock, Germany.; Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 Japan.; Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA.; Center for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany.; Sino German Joint Research Center for Agricultural Biology, and State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China.; BIOSS Center for Biological Signalling Studies, Albert-Ludwigs-University of Freiburg, Schanzlestrasse 18, D-79104 Freiburg, Germany.
Our current understanding of vein development in leaves is based on canalization of the plant hormone auxin into self-reinforcing streams which determine the sites of vascular cell differentiation. By comparison, how auxin biosynthesis affects leaf vein patterning is less well understood. Here, after observing that inhibiting polar auxin transport rescues the sparse leaf vein phenotype in auxin biosynthesis mutants, we propose that the processes of auxin biosynthesis and cellular auxin efflux work in concert during vein development. By using computational modeling, we show that localized auxin maxima are able to interact with mechanical forces generated by the morphological constraints which are imposed during early primordium development. This interaction is able to explain four fundamental characteristics of midvein morphology in a growing leaf: (i) distal cell division; (ii) coordinated cell elongation; (iii) a midvein positioned in the center of the primordium; and (iv) a midvein which is distally branched. Domains of auxin biosynthetic enzyme expression are not positioned by auxin canalization, as they are observed before auxin efflux proteins polarize. This suggests that the site-specific accumulation of auxin, as regulated by the balanced action of cellular auxin efflux and local auxin biosynthesis, is crucial for leaf vein formation.
PMID: 33263754
J Exp Bot , IF:5.908 , 2021 Feb , V72 (4) : P1119-1134 doi: 10.1093/jxb/eraa512
A genome-wide association study reveals that the glucosyltransferase OsIAGLU regulates root growth in rice.
The Laboratory of Seed Science and Technology, Guangdong Key Laboratory of Plant Molecular Breeding, Guangdong Laboratory of Lingnan Modern Agriculture, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, People's Republic of China.; College of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou, People's Republic of China.; Huzhou Agricultural Science and Technology Development Center, Huzhou, People's Republic of China.; Northeast Agricultural University, Harbin, People's Republic of China.
Good root growth in the early post-germination stages is an important trait for direct seeding in rice, but its genetic control is poorly understood. In this study, we examined the genetic architecture of variation in primary root length using a diverse panel of 178 accessions. Four QTLs for root length (qRL3, qRL6, qRL7, and qRL11) were identified using genome-wide association studies. One candidate gene was validated for the major QTL qRL11, namely the glucosyltransferase OsIAGLU. Disruption of this gene in Osiaglu mutants reduced the primary root length and the numbers of lateral and crown roots. The natural allelic variations of OsIAGLU contributing to root growth were identified. Functional analysis revealed that OsIAGLU regulates root growth mainly via modulating multiple hormones in the roots, including levels of auxin, jasmonic acid, abscisic acid, and cytokinin. OsIAGLU also influences the expression of multiple hormone-related genes associated with root growth. The regulation of root growth through multiple hormone pathways by OsIAGLU makes it a potential target for future rice breeding for crop improvement.
PMID: 33130882
J Exp Bot , IF:5.908 , 2021 Feb , V72 (4) : P1181-1197 doi: 10.1093/jxb/eraa495
The conserved brassinosteroid-related transcription factor BIM1a negatively regulates fruit growth in tomato.
INRAE, Univ. Bordeaux, UMR BFP, 33882, Villenave d'Ornon, France.; Instituto de Biotecnologia, Instituto Nacional de Tecnologia Agropecuaria, Consejo Nacional de Investigaciones Cientificas y Tecnicas, B1712WAA Castelar, Argentina.; Department of Plant Life Science, Faculty of Agriculture, Ryukoku University, Otsu, Shiga, Japan.; Department of Natural Sciences, International Christian University, Mitaka, Tokyo, Japan.; Faculty of Life and Environmental Sciences, University of Tsukuba, Tskuba, Ibaraki, Japan.; Tsukuba Plant Innovation Research Center, University of Tsukuba, Tskuba, Ibaraki, Japan.
Brassinosteroids (BRs) are steroid hormones that play key roles in plant development and defense. Our goal is to harness the extensive knowledge of the Arabidopsis BR signaling network to improve productivity in crop species. This first requires identifying components of the conserved network and their function in the target species. Here, we investigated the function of SlBIM1a, the closest tomato homolog of AtBIM1, which is highly expressed in fruit. SlBIM1a-overexpressing lines displayed severe plant and fruit dwarfism, and histological characterization of different transgenic lines revealed that SlBIM1a expression negatively correlated with fruit pericarp cell size, resulting in fruit size modifications. These growth phenotypes were in contrast to those found in Arabidopsis, and this was confirmed by the reciprocal ectopic expression of SlBIM1a/b in Arabidopsis and of AtBIM1 in tomato. These results determined that BIM1 function depends more on the recipient species than on its primary sequence. Yeast two-hybrid interaction studies and transcriptomic analyses of SlBIM1a-overexpressing fruit further suggested that SlBIM1a acts through its interaction with SlBZH1 to govern the transcriptional regulation of growth-related BR target genes. Together, these results suggest that SlBIM1a is a negative regulator of pericarp cell expansion, possibly at the crossroads with auxin and light signaling.
PMID: 33097930
J Exp Bot , IF:5.908 , 2021 Feb , V72 (2) : P459-475 doi: 10.1093/jxb/eraa485
Endogenous indole-3-acetamide levels contribute to the crosstalk between auxin and abscisic acid, and trigger plant stress responses in Arabidopsis.
Centro de Biotecnologia y Genomica de Plantas, Universidad Politecnica de Madrid (UPM) - Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), Pozuelo de Alarcon, Spain.; Lehrstuhl fur Pflanzenphysiologie, Ruhr-Universitat Bochum, Bochum, Germany.; Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden.; Gothenburg Global Biodiversity Centre, Gothenburg, Sweden.; Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.; Department of Infectious Diseases, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.; Departamento de Biotecnologia-Biologia Vegetal, Escuela Tecnica Superior de Ingenieria Agronomica, Alimentaria y de Biosistemas, Universidad Politecnica de Madrid (UPM), Madrid, Spain.
The evolutionary success of plants relies to a large extent on their extraordinary ability to adapt to changes in their environment. These adaptations require that plants balance their growth with their stress responses. Plant hormones are crucial mediators orchestrating the underlying adaptive processes. However, whether and how the growth-related hormone auxin and the stress-related hormones jasmonic acid, salicylic acid, and abscisic acid (ABA) are coordinated remains largely elusive. Here, we analyse the physiological role of AMIDASE 1 (AMI1) in Arabidopsis plant growth and its possible connection to plant adaptations to abiotic stresses. AMI1 contributes to cellular auxin homeostasis by catalysing the conversion of indole-acetamide into the major plant auxin indole-3-acetic acid. Functional impairment of AMI1 increases the plant's stress status rendering mutant plants more susceptible to abiotic stresses. Transcriptomic analysis of ami1 mutants disclosed the reprogramming of a considerable number of stress-related genes, including jasmonic acid and ABA biosynthesis genes. The ami1 mutants exhibit only moderately repressed growth but an enhanced ABA accumulation, which suggests a role for AMI1 in the crosstalk between auxin and ABA. Altogether, our results suggest that AMI1 is involved in coordinating the trade-off between plant growth and stress responses, balancing auxin and ABA homeostasis.
PMID: 33068437
J Exp Bot , IF:5.908 , 2021 Feb , V72 (2) : P320-340 doi: 10.1093/jxb/eraa430
Rab-dependent vesicular traffic affects female gametophyte development in Arabidopsis.
Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk, Poland.; Waite Research Institute, School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, South Australia, Australia.; LAQV REQUIMTE, Departamento de Biologia, Faculdade de Ciencias, Universidade do Porto, rua do Campo Alegre s/n Porto, Portugal.; Intercollegiate Faculty of Biotechnology, University of Gdansk, Abrahama 58, Gdansk, Poland.; Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, Warsaw, Poland.; Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, Praha 6 Lysolaje, Czech Republic.; Faculty of Biology, University of Warsaw, Miecznikowa 1, Warsaw, Poland.
Eukaryotic cells rely on the accuracy and efficiency of vesicular traffic. In plants, disturbances in vesicular trafficking are well studied in quickly dividing root meristem cells or polar growing root hairs and pollen tubes. The development of the female gametophyte, a unique haploid reproductive structure located in the ovule, has received far less attention in studies of vesicular transport. Key molecules providing the specificity of vesicle formation and its subsequent recognition and fusion with the acceptor membrane are Rab proteins. Rabs are anchored to membranes by covalently linked geranylgeranyl group(s) that are added by the Rab geranylgeranyl transferase (RGT) enzyme. Here we show that Arabidopsis plants carrying mutations in the gene encoding the beta-subunit of RGT (rgtb1) exhibit severely disrupted female gametogenesis and this effect is of sporophytic origin. Mutations in rgtb1 lead to internalization of the PIN1 and PIN3 proteins from the basal membranes to vesicles in provascular cells of the funiculus. Decreased transport of auxin out of the ovule is accompanied by auxin accumulation in tissue surrounding the growing gametophyte. In addition, female gametophyte development arrests at the uni- or binuclear stage in a significant portion of the rgtb1 ovules. These observations suggest that communication between the sporophyte and the developing female gametophyte relies on Rab-dependent vesicular traffic of the PIN1 and PIN3 transporters and auxin efflux out of the ovule.
PMID: 32939545
PLoS Genet , IF:5.174 , 2021 Feb , V17 (2) : Pe1009384 doi: 10.1371/journal.pgen.1009384
IAA3-Mediated repression of PIF proteins coordinates light and auxin signaling in Arabidopsis.
Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen, China.; The State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Joint Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, School of Life Sciences, Peking University, Beijing, China.; Institute of Plant and Food Science, Southern University of Science and Technology (SUSTech), Shenzhen, China.; Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology (SUSTech), Shenzhen, China.
The exogenous light signal and endogenous auxin are two critical factors that antagonistically regulate hypocotyl growth. However, the regulatory mechanisms integrating light and auxin signaling pathways need further investigation. In this study, we identified a direct link between the light and auxin signaling pathways mediated by the auxin transcriptional repressor IAA3 and light-controlled PIF transcription factors in Arabidopsis. The gain-of-function mutation in IAA3 caused hyposensitivity to light, whereas disruption of IAA3 led to an elongated hypocotyl under different light intensity conditions, indicating that IAA3 is required in light regulated hypocotyl growth. Genetic studies showed that the function of IAA3 in hypocotyl elongation is dependent on PIFs. Our data further demonstrated that IAA3 interacts with PIFs in vitro and in vivo, and it attenuates the DNA binding activities of PIFs to the target genes. Moreover, IAA3 negatively regulates the expression of PIFs-dependent genes. Collectively, our study reveals an interplay mechanism of light and auxin on the regulation of hypocotyl growth, coordinated by the IAA3 and PIFs transcriptional regulatory module.
PMID: 33600444
J Integr Plant Biol , IF:4.885 , 2021 Feb , V63 (2) : P340-352 doi: 10.1111/jipb.12992
Integrated metabolo-transcriptomics and functional characterization reveals that the wheat auxin receptor TIR1 negatively regulates defense against Fusarium graminearum.
State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Tai'an, 271018, China.; College of Information Science and Engineering, Shandong Agricultural University, Tai'an, 271018, China.
Fusarium head blight (FHB) caused by Fusarium graminearum Schwabe (teleomorph Gibberella zeae (Schw.) Perch) results in large yield losses in annual global wheat production. Although studies have identified a number of wheat FHB resistance genes, a deeper understanding of the mechanisms underlying host plant resistance to F. graminearum is required for the control of FHB. Here, an integrated metabolomics and transcriptomics analysis of infected wheat plants (Triticum aestivum L.) enabled identification of 789 differentially accumulated metabolites, including flavonoids, phenolamides, tryptamine derivatives, and phytohormones, and revealed altered expression of more than 100 genes that function in the biosynthesis or regulation of these pathways. Our data regarding the effects of F. graminearum infection on flavonoids and auxin signaling led to follow-up experiments that showed that exogenous kaempferide and apigenin application on spikes increased wheat resistance to FHB, while exogenous auxin treatment increased FHB susceptibility. RNAi-mediated knockdown of the gene encoding the auxin receptor, TaTIR1, increased FHB resistance. Our data supported the use of TaTIR1 knockdown in controlling FHB. Our study provides insights on the wheat response to F. graminearum infection and its FHB resistance mechanisms while illustrating the potential of TaTIR1 knockdown in increasing FHB resistance during crop improvement programs.
PMID: 32678930
Ecotoxicol Environ Saf , IF:4.872 , 2021 Apr , V212 : P112002 doi: 10.1016/j.ecoenv.2021.112002
Cadmium stress suppresses the tillering of perennial ryegrass and is associated with the transcriptional regulation of genes controlling axillary bud outgrowth.
College of Pratacultural Science, Gansu Agricultural University, Lanzhou, Gansu 730070, China.; Gansu Provincial Key Lab of Aridland Crop Science / Gansu Key Lab of Crop Improvement and Germplasm Enhancement, Lanzhou 730070, China.; College of Pratacultural Science, Gansu Agricultural University, Lanzhou, Gansu 730070, China. Electronic address: mahl@gsau.edu.cn.
Perennial ryegrass (Lolium perenne L.), a grass species with superior tillering capacity, plays a potential role in the phytoremediation of cadmium (Cd)-contaminated soils. Tiller production is inhibited in response to serious Cd stress. However, the regulatory mechanism of Cd stress-induced inhibition of tiller development is not well documented. To address this issue, we investigated the phenotype, the expression levels of genes involved in axillary bud initiation and bud outgrowth, and endogenous hormone biosynthesis and signaling pathways in seedlings of perennial ryegrass under Cd stress. The results showed that the number of tillers and axillary buds in the Cd-treated seedlings decreased by 67% and 21%, respectively. The suppression of tiller production in the Cd-treated seedlings was more closely associated with the inhibition of axillary bud outgrowth than with bud initiation. Cd stress upregulated the expression level of genes related to axillary bud dormancy and downregulated bud activity genes. Additionally, genes involved in strigolactone biosynthesis and signaling, auxin transport and signaling, and cytokinin degradation were upregulated in Cd-treated seedlings, and cytokinin biosynthesis gene expression were decreased by Cd stress. The content of zeatin in the Cd-treated pants was significantly reduced by 69~85% compared to the control plants. The content of indole-3-acetic acid (IAA) remains constant under Cd stress. Overall, Cd stress induced axillary bud dormancy and subsequently inhibited axillary bud outgrowth. The decrease of zeatin content and upregulation of genes involved in strigolactone signaling and bud dormancy might be responsible for the inhibition of axillary bud outgrowth.
PMID: 33529920
Int J Mol Sci , IF:4.556 , 2021 Feb , V22 (4) doi: 10.3390/ijms22041562
The Rice Small Auxin-Up RNA Gene OsSAUR33 Regulates Seed Vigor via Sugar Pathway during Early Seed Germination.
The Laboratory of Seed Science and Technology, Guangdong Key Laboratory of Plant Molecular Breeding, Guangdong Laboratory of Lingnan Modern Agriculture, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China.
Seed vigor affects seed germination and seedling emergence, and therefore is an important agronomic trait in rice. Small auxin-up RNAs (SAURs) function in a range of developmental processes, but their role in seed vigor remains unclear. Here, we observed that disruption of OsSAUR33 resulted in reduced germination rates and low seed uniformity in early germination. Expression of OsSAUR33 was higher in mature grains and early germinating seeds. RNA-seq analysis revealed that OsSAUR33 modulated seed vigor by affecting the mobilization of stored reserves during germination. Disruption of OsSAUR33 increased the soluble sugar content in dry mature grains and seeds during early germination. OsSAUR33 interacted with the sucrose non-fermenting-1-related protein kinase OsSnRK1A, a regulator of the sugar signaling pathway, which influences the expression of sugar signaling-related genes during germination. Disruption of OsSAUR33 increased sugar-sensitive phenotypes in early germination, suggesting OsSAUR33 likely affects seed vigor through the sugar pathway. One elite haplotype of OsSAUR33 associated with higher seed vigor was identified mainly in indica accessions. This study provides insight into the effects of OsSAUR33 on seed vigor in rice.
PMID: 33557166
Int J Mol Sci , IF:4.556 , 2021 Feb , V22 (4) doi: 10.3390/ijms22041505
Transcript Dynamics in Wounded and Inoculated Scots Pine.
Genetic Resource Centre, Latvian State Forest Research Institute "Silava", 111 Rigas st., LV-2169 Salaspils, Latvia.
Comparative transcriptome analysis provides a useful tool for the exploration of plant-pathogen interaction by allowing in-depth comparison of gene expression between unaffected, inoculated and wounded organisms. Here we present the results of comparative transcriptome analysis in genetically identical one-year-old Scots pine ramets after wounding and inoculation with Heterobasidion annosum. We identified 230 genes that were more than 2-fold upregulated in inoculated samples (compared to controls) and 116 downregulated genes. Comparison of inoculated samp les with wounded samples identified 32 differentially expressed genes (30 were upregulated after inoculation). Several of the genes upregulated after inoculation are involved in protection from oxidative stress, while genes involved in photosynthesis, water transport and drought stress tolerance were downregulated. An NRT3 family protein was the most upregulated transcript in response to both inoculation and wounding, while a U-box domain-containing protein gene was the most upregulated gene comparing inoculation to wounding. The observed transcriptome dynamics suggest involvement of auxin, ethylene, jasmonate, gibberellin and reactive oxygen species pathways and cell wall modification regulation in response to H. annosum infection. The results are compared to methyl jasmonate induced transcriptome dynamics.
PMID: 33546141
Front Plant Sci , IF:4.402 , 2021 , V12 : P573634 doi: 10.3389/fpls.2021.573634
The Photosynthetic Bacterium Rhodopseudomonas palustris Strain PS3 Exerts Plant Growth-Promoting Effects by Stimulating Nitrogen Uptake and Elevating Auxin Levels in Expanding Leaves.
Department of Agronomy, National Taiwan University, Taipei, Taiwan.; Institute of Biotechnology, National Taiwan University, Taipei, Taiwan.; Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan.
Rhodopseudomonas palustris strain PS3, a phototrophic bacterium, was originally isolated from a paddy field located in Taipei city, Taiwan, and showed positive effects on the growth of leafy vegetables. The aim of this study was to clarify the mechanism of the beneficial effects exerted by PS3 on plants. An ineffective R. palustris strain, YSC3, isolated from a paddy field located in Yilan County, was used as the negative control for comparative analyses. We cultivated non-heading Chinese cabbage (Brassica rapa var. chinensis) in 1/2 strength Hoagland hydroponic solution, in which nitrate is the main nitrogen source. We evaluated various plant physiological responses to inoculation with different bacterial inoculants. The N use efficiency (NUE) of PS3-inoculated plants was dramatically higher than that of YSC3-inoculated plants. The nitrate uptake efficiency (NUpE) was significantly elevated in plants treated with PS3; however, no excess nitrate accumulation was observed in leaves. We also noticed that the endogenous indole-3-acetic acid (IAA) levels as well as the cell division rate in the leaves of PS3-inoculated plants were significantly higher than those in the leaves of YSC3-inoculated plants. We examined the bacterial transcription of some genes during root colonization, and found that the expression level of IAA synthesis related gene MAO was almost the same between these two strains. It suggests that the elevated endogenous IAA in the PS3-inoculated plants was not directly derived from the exogenous IAA produced by this bacterium. Taken together, we deduced that PS3 inoculation could promote plant growth by enhancing nitrate uptake and stimulating the accumulation of endogenous auxin in young expanding leaves to increase the proliferation of leaf cells during leaf development.
PMID: 33613595
Front Plant Sci , IF:4.402 , 2020 , V11 : P608711 doi: 10.3389/fpls.2020.608711
Light Regulates the Cytokinin-Dependent Cold Stress Responses in Arabidopsis.
Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia.; Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia.; Department of Plant Physiology, Agricultural Institute, Centre for Agricultural Research, Martonvasar, Hungary.; CEITEC MENDELU: Central European Institute of Technology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia.
To elucidate the effect of light intensity on the cold response (5 degrees C; 7 days) in Arabidopsis thaliana, we compared the following parameters under standard light (150 mumol m(-2) s(-1)), low light (20 mumol m(-2) s(-1)), and dark conditions: membrane damage, photosynthetic parameters, cytokinin oxidase/dehydrogenase (CKX) activity, phytohormone levels, and transcription of selected stress- and hormone-related genes and proteome. The impact of cytokinins (CKs), hormones directly interacting with the light signaling pathway, on cold responses was evaluated using transformants overexpressing CK biosynthetic gene isopentenyl transferase (DEX:IPT) or CK degradation gene HvCKX2 (DEX:CKX) under a dexamethasone-inducible promoter. In wild-type plants, cold treatment under light conditions caused down-regulation of CKs (in shoots) and auxin, while abscisic acid (ABA), jasmonates, and salicylic acid (SA) were up-regulated, especially under low light. Cold treatment in the dark strongly suppressed all phytohormones, except ABA. DEX:IPT plants showed enhanced stress tolerance associated with elevated CK and SA levels in shoots and auxin in apices. Contrarily, DEX:CKX plants had weaker stress tolerance accompanied by lowered levels of CKs and auxins. Nevertheless, cold substantially diminished the impact from the inserted genes. Cold stress in dark minimized differences among the genotypes. Cold treatments in light strongly up-regulated stress marker genes RD29A, especially in roots, and CBF1-3 in shoots. Under control conditions, their levels were higher in DEX:CKX plants, but after 7-day stress, DEX:IPT plants exhibited the highest transcription. Transcription of genes related to CK metabolism and signaling showed a tendency to re-establish, at least partially, CK homeostasis in both transformants. Up-regulation of strigolactone-related genes in apices and leaves indicated their role in suppressing shoot growth. The analysis of leaf proteome revealed over 20,000 peptides, representing 3,800 proteins and 2,212 protein families (data available via ProteomeXchange, identifier PXD020480). Cold stress induced proteins involved in ABA and jasmonate metabolism, antioxidant enzymes, and enzymes of flavonoid and glucosinolate biosynthesis. DEX:IPT plants up-regulated phospholipase D and MAP-kinase 4. Cold stress response at the proteome level was similar in all genotypes under optimal light intensity, differing significantly under low light. The data characterized the decisive effect of light-CK cross-talk in the regulation of cold stress responses.
PMID: 33613584
Front Plant Sci , IF:4.402 , 2021 , V12 : P621587 doi: 10.3389/fpls.2021.621587
Tissue-Specific Hormonal Variations in Grapes of Irrigated and Non-irrigated Grapevines (Vitis vinifera cv. "Merlot") Growing Under Mediterranean Field Conditions.
Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Barcelona, Spain.; Research Institute of Nutrition and Food Safety, University of Barcelona, Barcelona, Spain.
Agricultural practices in grapevines management include water restrictions due to its positive effect on wine quality, especially when applied at fruit ripening. Although the effects of water stress in some groups of phytohormones have already been described in leaves and whole grapes, information regarding tissue-specific variations in hormones during ripening in grapes is scarce. Field-grown grapevines from the cv. "Merlot" were subjected to two differential water supplies, including only rainfed, non-irrigated vines (T0) and vines additionally irrigated with 25Lweek(-1) vine(-1) (T1). Tissue-specific variations in the hormonal profiling of grapes [including changes in the contents of abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), the ethylene precursor 1-amino-cyclopropane-1-carboxylic acid (ACC), the auxin indole-3-acetic acid, gibberellins 1, 3, 4, and 7 (GA1, GA3, GA4, and GA7), the cytokinins trans-zeatin, and 2-isopentenyl adenine, including as well their respective ribosylated forms] were periodically evaluated from veraison to harvest. The hormonal profiling in leaves was also measured at the beginning and end of the season for comparison. Results showed that grape growth dynamics were transiently affected by the differences in water regimes, the increased water supply leading to an accelerated growth, slightly reduced accumulation of sugars, and transiently lowered pH, although grape quality did not differ between treatments at harvest. Hormonal profiling of whole berries did not reveal any difference in the endogenous contents of phytohormones between treatments, except for a transient decrease in GA4 contents in T1 compared to T0 vines, which was not confirmed at the tissular level. Hormonal profiling at the tissue level highlighted a differential accumulation of phytohormones during ripening in berry tissues, with pulps being particularly poor in ABA, JA, and SA contents, seeds particularly accumulating ACC, gibberellins, and zeatin-type cytokinins, and the skin being particularly rich in auxin and active cytokinins. Changes in water supply led to very small and transient changes in the endogenous contents of phytohormones in the seeds, pulp, and skin of berries, the most remarkable variations being observed in cytokinin contents, which increased earlier [between 5 and 12days after veraison (DAV)] but later kept more constant in the skin from T1 compared to T0 vines and were also 3-fold higher at 40 DAV in seeds of T1 compared to T0 vines. It is concluded that small changes in water supply can trigger hormonal-driven physiological adjustments at the tissular level affecting the evolution of fruit growth and quality throughout grape berry ripening.
PMID: 33597962
Commun Biol , IF:4.165 , 2021 Feb , V4 (1) : P206 doi: 10.1038/s42003-021-01733-x
Function of histone H2B monoubiquitination in transcriptional regulation of auxin biosynthesis in Arabidopsis.
Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, P.R. China.; College of Life Science and Technology, Gansu Agricultural University, Lanzhou, Gansu, P.R. China.; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, P.R. China.; Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, P.R. China. zhaochm@lzu.edu.cn.; State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, P.R. China. zhaochm@lzu.edu.cn.; Institute of Cell Biology and MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, P.R. China. gqguo@lzu.edu.cn.
The auxin IAA is a vital plant hormone in controlling growth and development, but our knowledge about its complicated biosynthetic pathways and molecular regulation are still limited and fragmentary. cytokinin induced root waving 2 (ckrw2) was isolated as one of the auxin-deficient mutants in a large-scale forward genetic screen aiming to find more genes functioning in auxin homeostasis and/or its regulation. Here we show that CKRW2 is identical to Histone Monoubiquitination 1 (HUB1), a gene encoding an E3 ligase required for histone H2B monoubiquitination (H2Bub1) in Arabidopsis. In addition to pleiotropic defects in growth and development, loss of CKRW2/HUB1 function also led to typical auxin-deficient phenotypes in roots, which was associated with significantly lower expression levels of several functional auxin synthetic genes, namely TRP2/TSB1, WEI7/ASB1, YUC7 and AMI1. Corresponding defects in H2Bub1 were detected in the coding regions of these genes by chromatin immunoprecipitation (ChIP) analysis, indicating the involvement of H2Bub1 in regulating auxin biosynthesis. Importantly, application of exogenous cytokinin (CK) could stimulate CKRW2/HUB1 expression, providing an epigenetic avenue for CK to regulate the auxin homeostasis. Our results reveal a previously unknown mechanism for regulating auxin biosynthesis via HUB1/2-mediated H2Bub1 at the chromatin level.
PMID: 33589721
Plant Cell Physiol , IF:4.062 , 2021 Feb doi: 10.1093/pcp/pcab028
EIN3-Mediated Ethylene Signaling Attenuates Auxin Response during Hypocotyl Thermomorphogenesis.
Department of Chemistry, Seoul National University, Seoul, 08826, Korea.; Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea.
The gaseous phytohormone ethylene plays vital roles in diverse developmental and environmental adaptation processes, such as fruit ripening, seedling establishment, mechanical stress tolerance, and submergence escape. It is also known that in the light, ethylene promotes hypocotyl growth by stimulating the expression of PHYTOCHROME INTERACTING FACTOR3 (PIF3) transcription factor, which triggers microtubule reorganization during hypocotyl cell elongation. In particular, ethylene has been implicated in plant responses to warm temperatures in recent years. However, it is currently unclear how ethylene signals are functionally associated with hypocotyl thermomorphogenesis at the molecular level. Here, we show that ETHYLENE-INSENSITIVE3 (EIN3)-mediated ethylene signals attenuate hypocotyl thermomorphogenesis by suppressing auxin response. At warm temperatures, when the activity of the PIF4 thermomorphogenesis promoter is prominently high, the ethylene-activated EIN3 transcription factor directly induces the transcription of ARABIDOPSIS PP2C CLADE D7 (APD7) gene encoding a protein phosphatase that inactivates the plasma membrane (PM) H+-ATPase proton pumps. In conjunction with the promotive role of the PM H+-ATPases in hypocotyl cell elongation, our observations strongly support that the EIN3-directed induction of APD7 gene is linked with the suppression of auxin-induced cell expansion, leading to the reduction of thermomorphogenic hypocotyl growth. Our data demonstrate that APD7 acts as a molecular hub that integrates ethylene and auxin signals into hypocotyl thermomorphogenesis. We propose that the ethylene-auxin signaling crosstalks via the EIN3-APD7 module facilitate the fine-tuning of hypocotyl thermomorphogenesis under natural environments, which often fluctuate in a complex manner.
PMID: 33594435
Plant Cell Physiol , IF:4.062 , 2021 Feb , V61 (12) : P2111-2125 doi: 10.1093/pcp/pcaa131
LAZY1 Controls Tiller Angle and Shoot Gravitropism by Regulating the Expression of Auxin Transporters and Signaling Factors in Rice.
Rice Research Institute, College of Agronomy, Shenyang Agricultural University, No.120 Dongling Road, Shenhe District, Shenyang 110866, China.; Department of Foreign Language, Shenyang Agricultural University.
Tiller angle is a key factor determining rice plant architecture, planting density, light interception, photosynthetic efficiency, disease resistance and grain yield. However, the mechanisms underlying tiller angle control are far from clear. In this study, we identified a mutant, termed bta1-1, with an enlarged tiller angle throughout its life cycle. A detailed analysis reveals that BTA1 has multiple functions because tiller angle, shoot gravitropism and tolerance to drought stress are changed in bta1-1 plants. Moreover, BTA1 is a positive regulator of shoot gravitropism in rice. Shoot responses to gravistimulation are disrupted in bta1-1 under both light and dark conditions. Gene cloning reveals that bta1-1 is a novel mutant allele of LA1 renamed la1-SN. LA1 is able to rescue the tiller angle and shoot gravitropism defects observed in la1-SN. The nuclear localization signal of LA1 is disrupted by la1-SN, causing changes in its subcellular localization. LA1 is required to regulate the expression of auxin transporters and signaling factors that control shoot gravitropism and tiller angle. High-throughput mRNA sequencing is performed to elucidate the molecular and cellular functions of LA1. The results show that LA1 may be involved in the nucleosome and chromatin assembly, and protein-DNA interactions to control gene expression, shoot gravitropism and tiller angle. Our results provide new insight into the mechanisms whereby LA1 controls shoot gravitropism and tiller angle in rice.
PMID: 33067639
Appl Environ Microbiol , IF:4.016 , 2021 Feb doi: 10.1128/AEM.02989-20
A stringent response-defective Bradyrhizobium diazoefficiens does not activate the type-3-secretion system, elicits early plant defense, and circumvents NH4NO3-induced inhibition of nodulation.
IBBM, Facultad de Ciencias Exactas. CCT-La Plata CONICET y Universidad Nacional de La Plata. La Plata, Argentina.; Center for Synthetic Microbiology (SYNMIKRO); Department of Biology, Philipps-Universitat Marburg, Germany.; Fundacion Instituto Leloir, Instituto de Investigaciones Bioquimicas de Buenos Aires-CONICET, Buenos Aires, Argentina.; Centro de Biotecnologia Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello and Millennium Institute for Integrative Biology (iBio), Santiago, Chile.; IBBM, Facultad de Ciencias Exactas. CCT-La Plata CONICET y Universidad Nacional de La Plata. La Plata, Argentina lodeiro@biol.unlp.edu.ar.; Laboratorio de Genetica, Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata. La Plata, Argentina.
When subjected to nutritional stress, bacteria modify their amino acid metabolism and cell division activities by means of the stringent response, which is controlled by the Rsh protein in alphaproteobacteria. An important group of alphaproteobacteria are the rhizobia, which fix atmospheric N2 in symbiosis with legume plants. Although nutritional stress is common for rhizobia while infecting legume roots, the stringent response was scarcely studied in this group of soil bacteria. In this report, we obtained a mutant in the rsh gene of Bradyrhizobium diazoefficiens, the N2-fixing symbiont of soybean. This mutant was defective for type-3-secretion system induction, plant-defense suppression at early root infection, and competition for nodulation. Furthermore, the mutant produced smaller nodules, although with normal morphology, which lead to lower plant biomass production. Soybean genes GmRIC1 and GmRIC2, involved in autoregulation of nodulation, were upregulated in plants inoculated with the mutant in N-free condition. In addition, when plants were inoculated in the presence of 10 mM NH4NO3, the mutant produced nodules containing bacteroids, and GmRIC1 and GmRIC2 were downregulated. The rsh mutant released more auxin to the culture supernatant than the wild type, which might in part explain its symbiotic behavior in the presence of combined-N. These results indicate that B. diazoefficiens stringent response integrates into the plant defense suppression and regulation of nodulation circuits in soybean, perhaps mediated by the type-3-secretion system.IMPORTANCE The symbiotic N2 fixation carried out between prokaryotic rhizobia and legume plants performs a substantial contribution to the N-cycle in the biosphere. This symbiotic association is initiated when rhizobia infect and penetrate the root hairs, which is followed by the growth and development of root nodules within which the infective rhizobia are established and protected. Thus, the nodule environment allows the expression and function of the enzyme complex that catalyzes N2 fixation. However, during early infection the rhizobia find a harsh environment while penetrating the root hairs. To cope with this nuisance, the rhizobia mount a stress response known as stringent response. In turn, the plant regulates nodulation in response to the presence of alternative sources of combined-N in the surrounding medium. Control of these processes is crucial for a successful symbiosis, and here we show how the rhizobial stringent response may modulate plant defense suppression and the networks of regulation of nodulation.
PMID: 33608284
Sci Rep , IF:3.998 , 2021 Feb , V11 (1) : P4260 doi: 10.1038/s41598-021-83629-8
Gene expression patterns in shoots of Camelina sativa with enhanced salinity tolerance provided by plant growth promoting bacteria producing 1-aminocyclopropane-1-carboxylate deaminase or expression of the corresponding acdS gene.
Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada.; Department of Biotechnology, School of Agriculture, University of Shiraz, Bajgah, Shiraz, Fars, Iran.; Department of Biology, University of Waterloo, Waterloo, ON, Canada.; Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada. dwayne.hegedus@canada.ca.; Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada. dwayne.hegedus@canada.ca.
Growth of plants in soil inoculated with plant growth promoting bacteria (PGPB) producing 1-aminocyclopropane-1-carboxylate (ACC) deaminase or expression of the corresponding acdS gene in transgenic lines reduces the decline in shoot length, shoot weight and photosynthetic capacity triggered by salt stress in Camelina sativa. Reducing the levels of ethylene attenuated the salt stress response as inferred from decreases in the expression of genes involved in development, senescence, chlorosis and leaf abscission that are highly induced by salt to levels that may otherwise have a negative effect on plant growth and productivity. Growing plants in soil treated with Pseudomonas migulae 8R6 negatively affected ethylene signaling, auxin and JA biosynthesis and signalling, but had a positive effect on the regulation of genes involved in GA signaling. In plants expressing acdS, the expression of the genes involved in auxin signalling was positively affected, while the expression of genes involved in cytokinin degradation and ethylene biosynthesis were negatively affected. Moreover, fine-tuning of ABA signaling appears to result from the application of ACC deaminase in response to salt treatment. Moderate expression of acdS under the control of the root specific rolD promoter or growing plants in soil treated with P. migulae 8R6 were more effective in reducing the expression of the genes involved in ethylene production and/or signaling than expression of acdS under the more active Cauliflower Mosaic Virus 35S promoter.
PMID: 33608579
Sci Rep , IF:3.998 , 2021 Feb , V11 (1) : P3976 doi: 10.1038/s41598-021-83519-z
Crosstalk between auxin and gibberellin during stalk elongation in flowering Chinese cabbage.
College of Horticulture, South China Agricultural University, Guangzhou, China.; College of Horticulture, South China Agricultural University, Guangzhou, China. yanweihao@scau.edu.cn.; College of Horticulture, South China Agricultural University, Guangzhou, China. swsong@scau.edu.cn.
Plant growth and development are tightly regulated by phytohormones. However, little is known about the interaction between auxin and gibberellin acid (GA) during flower stalk elongation and how it is directly related to organ formation. Therefore, the effects of indole acetic acid (IAA) and GA3 treatments and their interaction on flower stalk elongation in flowering Chinese cabbage were investigated. The growth of flowering Chinese cabbage is regulated by IAA and GA3, and the opposite results were observed after treatments with uniconazole (GA synthesis inhibitor) and N-1-naphthylphthalamic acid (NPA) (auxin transport inhibitor). Anatomical analysis of the pith region in stalks revealed that IAA promoted expansion via signal transduction and transport pathways. GA3 regulated the elongation of flower stalks by controlling GA synthesis and partially controlling the IAA signaling pathway. GA3 also had a stronger effect on stalk elongation than IAA. The results of qRT-PCR and histological analysis revealed that GA3 and IAA induced the expansion of cell walls by activating the expression of genes encoding cell wall structural proteins such as Expansin (EXP). These findings provide new insights into the mechanism of stalk formation regulated by the combination of IAA and GA3.
PMID: 33597591
Plant Cell Rep , IF:3.825 , 2021 Feb , V40 (2) : P315-325 doi: 10.1007/s00299-020-02633-w
ARF4 regulates shoot regeneration through coordination with ARF5 and IAA12.
State Key Laboratory of Crop Biology, College of Life Sciences, College of Forestry, State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, Shandong Agricultural University, Tai'an, 271018, Shandong, China.; State Key Laboratory of Crop Biology, College of Life Sciences, College of Forestry, State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, Shandong Agricultural University, Tai'an, 271018, Shandong, China. sangyl@sdau.edu.cn.; State Key Laboratory of Crop Biology, College of Life Sciences, College of Forestry, State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, Shandong Agricultural University, Tai'an, 271018, Shandong, China. chengzj@sdau.edu.cn.
KEY MESSAGE: ARF4-regulated shoot regeneration through competing with ARF5 for the interaction with IAA12. Plant possess the ability to regenerate shoot meristem and subsequent the whole individual. This process is the foundation for in vitro propagation and genetic engineering and provides a system for studying fundamental biological questions, such as hormonal signaling. Auxin response factor (ARF) family transcription factors are critical components of auxin signaling pathway that regulate the transcription of target genes. To date, the mechanisms underlying the functions of class-B ARFs which act as transcription repressors remains unclear. In this study, we found that ARF4, the transcriptional repressor, was involved in regulating shoot regeneration. ARF4 interacted with auxin/Indole-3-Acetic-Acid12 (IAA12). The expression signals of ARF4 displayed a dynamic pattern similar with those of ARF5 and IAA12 during shoot meristem formation. Enhanced expression of IAA12 compromised the shoot regeneration capacity. Induced expression of ARF4 complemented the regeneration phenotype of IAA12-overexpression but did not rescued the defects in the arf5 mutant, mp-S319. Further analysis revealed that ARF4 competed with ARF5 for the interaction with IAA12. The results indicate that ARF4-regulated shoot regeneration through cooperating with ARF5 and IAA12. Our findings provided new information for deciphering the function of class-B ARFs.
PMID: 33180161
Plant Cell Rep , IF:3.825 , 2021 Feb , V40 (2) : P301-314 doi: 10.1007/s00299-020-02631-y
Seed-specific expression of TaYUC10 significantly increases auxin and protein content in wheat seeds.
State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Tai'an, 271018, China.; State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Tai'an, 271018, China. dsfeng@sdau.edu.cn.
KEY MESSAGE: Present study revealed that specific expression of TaYUC10.3 in wheat young seeds could increase the content of auxin, and protein. Auxin is a vital endogenous hormone in plants, which is involved in the regulation of various physiological and biochemical processes in plants. The flavin-containing monooxygenase encoded by the YUCCA gene is a rate-limiting enzyme in the tryptophan-dependent pathway of auxin synthesis. TaYUC10.3 was identified, cloned and found that it was abundantly expressed in wheat young seeds. In this study, a seed-specific expression vector of TaYUC10.3 was constructed with the promoter of 1Bx17 glutenin subunit gene and transformed wheat using the particle bombardment method. The quantitative RT-PCR showed that TaYUC10.3 was expressed in a large amount in young seeds of the transgenic lines. Plant hormone-targeted metabolomics showed that the auxin content of the transgenic lines was significantly increased compared with controls. The GC / MS non-targeted metabolite multiple statistical analyses showed that the variable importance in projection (VIP) of tryptophan reduced in the transgenic lines. Simultaneously, the VIP of indole acetic acid increased. The precursor amino acids for synthesizing some proteins and carbohydrates were upregulated in the transgenic lines. Subsequently, it was found that the protein content of the seeds of the transgenic TaYUC10.3 wheat was significantly higher than that of the control. The wet gluten content and sedimentation value of the transgenic TaYUC10.3 wheat were also high. This result indicated that TaYUC10.3 might participate in auxin synthesis and affects the protein content of wheat seeds.
PMID: 33179162
Plant Cell Rep , IF:3.825 , 2021 Feb , V40 (2) : P271-282 doi: 10.1007/s00299-020-02612-1
Cytokinins as central regulators during plant growth and stress response.
Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, 250014, Shandong, China.; State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China.; Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, 250014, Shandong, China. suina@sdnu.edu.cn.
KEY MESSAGE: Cytokinins are a class of phytohormone that participate in the regulation of the plant growth, development, and stress response. In this review, the potential regulating mechanism during plant growth and stress response are discussed. Cytokinins are a class of phytohormone that participate in the regulation of plant growth, physiological activities, and yield. Cytokinins also play a key role in response to abiotic stresses, such as drought, salt and high or low temperature. Through the signal transduction pathway, cytokinins interact with various transcription factors via a series of phosphorylation cascades to regulate cytokinin-target gene expression. In this review, we systematically summarize the biosynthesis and metabolism of cytokinins, cytokinin signaling, and associated gene regulation, and highlight the function of cytokinins during plant development and resistance to abiotic stress. We also focus on the importance of crosstalk between cytokinins and other classes of phytohormones, including auxin, ethylene, strigolactone, and gibberellin. Our aim is to provide a comprehensive overview of recent findings on the mechanisms by which cytokinins act as central regulators of plant development and stress reactions, and highlight topics for future research.
PMID: 33025178
Biology (Basel) , IF:3.796 , 2021 Feb , V10 (2) doi: 10.3390/biology10020127
Comprehensive Analysis and Expression Profiling of PIN, AUX/LAX, and ABCB Auxin Transporter Gene Families in Solanum tuberosum under Phytohormone Stimuli and Abiotic Stresses.
State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China.; Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan 430071, China.; College of Food Science and Engineering, Northwest A&F University, Yangling 712100, China.
Auxin is the only plant hormone that exhibits transport polarity mediated by three families: auxin resistant (AUX) 1/like AUX1 (LAX) influx carriers, pin-formed (PIN) efflux carriers, and ATP-binding cassette B (ABCB) influx/efflux carriers. Extensive studies about the biological functions of auxin transporter genes have been reported in model plants. Information regarding these genes in potato remains scarce. Here, we conducted a comprehensive analysis of auxin transporter gene families in potato to examine genomic distributions, phylogeny, co-expression analysis, gene structure and subcellular localization, and expression profiling using bioinformatics tools and qRT-PCR analysis. From these analyses, 5 StLAXs, 10 StPINs, and 22 StABCBs were identified in the potato genome and distributed in 10 of 18 gene modules correlating to the development of various tissues. Transient expression experiments indicated that three representative auxin transporters showed plasma membrane localizations. The responsiveness to auxin and auxin transport inhibitors implied their possible roles in mediating intercellular auxin homoeostasis and redistribution. The differential expression under abscisic acid and abiotic stresses indicated their specific adaptive mechanisms regulating tolerance to environmental stimuli. A large number of auxin-responsive and stress-related cis-elements within their promoters could account for their responsiveness to diverse stresses. Our study aimed to understand the biological significance of potato auxin transporters in hormone signaling and tolerance to environmental stresses.
PMID: 33562678
Pest Manag Sci , IF:3.75 , 2021 Feb , V77 (2) : P795-804 doi: 10.1002/ps.6080
A dicamba resistance-endowing IAA16 mutation leads to significant vegetative growth defects and impaired competitiveness in kochia (Bassia scoparia)(dagger).
Bayer CropScience, Chesterfield, MO, USA.; Department of Agricultural Biology, Colorado State University, Wentzville, MO, USA.; Sammons BFC LLC, Wentzville, Wentzville, MO, 63365, USA.
BACKGROUND: Precise quantification of the fitness cost of synthetic auxin resistance has been impeded by lack of knowledge about the genetic basis of resistance in weeds. Recent elucidation of a resistance-endowing IAA16 mutation (G73N) in the key weed species kochia (Bassia scoparia), allows detailed characterization of the contribution of resistance alleles to weed fitness, both in the presence and absence of herbicides. Different G73N genotypes from a segregating resistant parental line (9425) were characterized for cross-resistance to dicamba, 2,4-d and fluroxypyr, and changes on stem/leaf morphology and plant architecture. Plant competitiveness and dominance of the fitness effects was quantified through measuring biomass and seed production of three F2 lines in two runs of glasshouse replacement series studies. RESULTS: G73N confers robust resistance to dicamba but only moderate to weak resistance to 2,4-D and fluroxypyr. G73N mutant plants displayed significant vegetative growth defects: (i) they were 30-50% shorter, with a more tumbling style plant architecture, and (ii) they had thicker and more ovate (versus lanceolate and linear) leaf blades with lower photosynthesis efficiency, and 40-60% smaller stems with less-developed vascular bundle systems. F2 mutant plants had impaired plant competitiveness, which can lead to 80-90% less biomass and seed production in the replacement series study. The pleiotropic effects of G73N were mostly semidominant (0.5) and fluctuated with the environments and traits measured. CONCLUSION: G73N is associated with significant vegetative growth defects and reduced competitiveness in synthetic auxin-resistant kochia. Management practices should target resistant kochia's high vulnerability to competition in order to effectively contain the spread of resistance.
PMID: 32909332
Plant Physiol Biochem , IF:3.72 , 2021 Feb , V161 : P131-142 doi: 10.1016/j.plaphy.2021.01.046
Calcium lignosulfonate improves proliferation of recalcitrant indica rice callus via modulation of auxin biosynthesis and enhancement of nutrient absorption.
Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia. Electronic address: wanmuhamadasrul@gmail.com.; Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia. Electronic address: ngaipaing@upm.edu.my.; Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia. Electronic address: klein9201@gmail.com.; Faculty of Applied Sciences, UCSI University, Kuala Lumpur, Malaysia. Electronic address: lohjy@ucsiuniversity.edu.my.; Biotechnology and Nanotechnology Research Centre, MARDI Headquarters, Persiaran MARDI-UPM, Serdang, Selangor, Malaysia. Electronic address: cywee@mardi.gov.my.; Malaysia Genome Institute (MGI) National Institute of Biotechnology Malaysia (NIBM), Kajang, Selangor, Malaysia. Electronic address: azneyzuhaily@nibm.my.; Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia. Electronic address: janna@upm.edu.my.; Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, Abu Dhabi, United Arab Emirates. Electronic address: lkoksong@hct.ac.ae.
Lignosulfonate (LS) is a commonly used to promote plant growth. However, the underlying growth promoting responses of LS in plant remain unknown. Therefore, this study was undertaken to elucidate the underlying growth promoting mechanisms of LS, specifically calcium lignosulfonate (CaLS). Addition of 100 mg/L CaLS in phytohormone-free media enhanced recalcitrant indica rice cv. MR219 callus proliferation rate and adventitious root formation. Both, auxin related genes (OsNIT1, OsTAA1 and OsYUC1) and tryptophan biosynthesis proteins were upregulated in CaLS-treated calli which corroborated with increased of endogenous auxin content. Moreover, increment of OsWOX11 gene on CaLS-treated calli implying that the raised of endogenous auxin was utilized as a cue to enhance adventitious root development. Besides, CaLS-treated calli showed higher nutrient ions content with major increment in calcium and potassium ions. Consistently, increased of potassium protein kinases genes (OsAKT1, OsHAK5, OsCBL, OsCIPK23 and OsCamk1) were also recorded. In CaLS treated calli, the significant increase of calcium ion was observed starting from week one while potassium ion only recorded significant increase on week two onwards, suggesting that increment of potassium ion might be dependent on the calcium ion content in the plant cell. Additionally, reduced callus blackening was also coherent with downregulation of ROS scavenging protein and reduced H2O2 content in CaLS-treated calli suggesting the role of CaLS in mediating cellular homeostasis via prevention of oxidative burst in the cell. Taken together, CaLS successfully improved MR219 callus proliferation and root formation by increasing endogenous auxin synthesis, enhancing nutrients uptake and regulating cellular homeostasis.
PMID: 33581621
Plant Physiol Biochem , IF:3.72 , 2021 Feb , V159 : P257-267 doi: 10.1016/j.plaphy.2020.12.027
Maize transcription factor ZmEREB20 enhanced salt tolerance in transgenic Arabidopsis.
Institute of Ecological Agriculture, Sichuan Agricultural University, Chengdu, 611130, China.; Institute of Ecological Agriculture, Sichuan Agricultural University, Chengdu, 611130, China; State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Chengdu, 611130, China. Electronic address: qwang@sicau.edu.cn.
Soil salinity severely limits agricultural crop production worldwide. As one of the biggest plant specific transcription factor families, AP2/ERF members have been extensively studied to regulate plant growth, development and stress responses. However, the role of AP2/ERF family in maize salt tolerance remains largely unknown. In this study, we identified a maize AP2-ERF family member ZmEREB20 as a positive salinity responsive gene. Overexpression of ZmEREB20in Arabidopsis enhanced ABA sensitivity and resulted in delayed seed germination under salt stress through regulating ABA and GA related genes. ZmEREB20 overexpression lines also showed higher survival rates with elevated ROS scavenging toward high salinity. Furthermore, root hair growth inhibition by salt stress was markedly rescued in ZmEREB20 overexpression lines. Auxin transport inhibitor TIBA drastically enhanced root hair growth in ZmEREB20 overexpression Arabidopsis under salt stress, together with the increased expression of auxin-related genes, ion transporter genes and root hair growth genes by RNA-seq analysis. ZmEREB20 positively regulated salt tolerance through the molecular mechanism associated with hormone signaling, ROS scavenging and root hair plasticity, proving the potential target for crop breeding to improve salt resistance.
PMID: 33395583
Plant Physiol Biochem , IF:3.72 , 2021 Feb , V159 : P179-192 doi: 10.1016/j.plaphy.2020.12.018
Regulation of growth in peach roots by exogenous hydrogen sulfide based on RNA-Seq.
State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, 271018, China.; State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, 271018, China. Electronic address: pft@sdau.edu.cn.; State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, 271018, China. Electronic address: ysxiao@sdau.edu.cn.
Hydrogen sulfide (H2S) has been shown to regulate many physiological processes of plants. In this study, we observed that 0.2 mM sodium hydrosulfide (NaHS), a donor of H2S, can regulate the root architecture of peach seedlings, increasing the number of lateral roots by 40.63%. To investigate the specific mechanisms by which H2S regulates root growth in peach, we used RNA sequencing and heterologous expression technology. Our results showed that exogenous H2S led to a 44.50% increase in the concentration of endogenous auxin. Analyses of differentially expressed genes (DEGs) revealed that 963 and 1113 genes responded to H2S on days one and five of treatment, respectively. Among the DEGs, 26 genes were involved in auxin biosynthesis, transport, and signal transduction. Using weighted correlation network analysis, we found that the auxin-related genes in the H2S-specific gene module were disproportionately involved in polar transport, which may play an important role in H2S-induced root growth. In addition, we observed that the expression of LATERAL ORGAN BOUNDARIES DOMAIN 16 (PpLBD16) was significantly up-regulated by exogenous application of H2S in peach. Overexpression of PpLBD16 in an Arabidopsis system yielded a 66.83% increase in the number of lateral roots. Under exposure to exogenous H2S, there was also increased expression of genes related to cell proliferation, indicating that H2S regulates the growth of peach roots. Our work represents the first comprehensive transcriptomic analysis of the effects of exogenous application of H2S on the roots of peach, and provides new insights into the mechanisms underlying H2S-induced root growth.
PMID: 33383385
Mol Plant Microbe Interact , IF:3.696 , 2021 Feb : PMPMI08200233R doi: 10.1094/MPMI-08-20-0233-R
A Network of Phosphate Starvation and Immune-Related Signaling and Metabolic Pathways Controls the Interaction between Arabidopsis thaliana and the Beneficial Fungus Colletotrichum tofieldiae.
Max Planck Institute for Plant Breeding Research, Department of Plant Microbe Interactions and Cluster of Excellence on Plant Sciences (CEPLAS), D-50829 Cologne, Germany.; Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznan, Poland.; Lehrstuhl fur Molekulargenetik und Physiologie der Pflanzen, Ruhr-Universitat Bochum, D-44801 Bochum, Germany.
The beneficial root-colonizing fungus Colletotrichum tofieldiae mediates plant growth promotion (PGP) upon phosphate (Pi) starvation in Arabidopsis thaliana. This activity is dependent on the Trp metabolism of the host, including indole glucosinolate (IG) hydrolysis. Here, we show that C. tofieldiae resolves several Pi starvation-induced molecular processes in the host, one of which is the downregulation of auxin signaling in germ-free plants, which is restored in the presence of the fungus. Using CRISPR/Cas9 genome editing, we generated an Arabidopsis triple mutant lacking three homologous nitrilases (NIT1 to NIT3) that are thought to link IG-hydrolysis products with auxin biosynthesis. Retained C. tofieldiae-induced PGP in nit1/2/3 mutant plants demonstrated that this metabolic connection is dispensable for the beneficial activity of the fungus. This suggests that either there is an alternative metabolic link between IG-hydrolysis products and auxin biosynthesis, or C. tofieldiae restores auxin signaling independently of IG metabolism. We show that C. tofieldiae, similar to pathogenic microorganisms, triggers Arabidopsis immune pathways that rely on IG metabolism as well as salicylic acid and ethylene signaling. Analysis of IG-deficient myb mutants revealed that these metabolites are, indeed, important for control of in planta C. tofieldiae growth: however, enhanced C. tofieldiae biomass does not necessarily negatively correlate with PGP. We show that Pi deficiency enables more efficient colonization of Arabidopsis by C. tofieldiae, possibly due to the MYC2-mediated repression of ethylene signaling and changes in the constitutive IG composition in roots.[Formula: see text] Copyright (c) 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
PMID: 33226310
Plant Sci , IF:3.591 , 2021 Feb , V303 : P110771 doi: 10.1016/j.plantsci.2020.110771
NIN-like protein 7 promotes nitrate-mediated lateral root development by activating transcription of TRYPTOPHAN AMINOTRANSFERASE RELATED 2.
Xinjiang Production and Construction Corps Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization, Department of Horticulture, College of Agriculture, Shihezi University, Shihezi, 832003, Xinjiang, China; State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center for Fruit and Vegetable Production with High Quality and Efficiency, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, 271018, Shandong, China.; State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center for Fruit and Vegetable Production with High Quality and Efficiency, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, 271018, Shandong, China.; Shandong Fruit and Tea Technology Services, Jinan, 250013, Shandong, China.; State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center for Fruit and Vegetable Production with High Quality and Efficiency, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, 271018, Shandong, China. Electronic address: xfwang2004@163.com.; State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center for Fruit and Vegetable Production with High Quality and Efficiency, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, 271018, Shandong, China. Electronic address: haoyujin@sdau.edu.cn.
Nitrate is essential for plant growth and development. When nitrate availability is low, plants produce more lateral roots (LRs) to seek nitrate from the soil. In this study, by DNA electrophoretic mobility shift and luciferase assays, it was showed that NIN-like protein 7 (NLP7) transcription factor activated expression of TAR2 by directly binding to its promoter. Finally, through genetic analysis, it was speculated that NLP7 regulated LR development through TAR2. In conclusion, NLP7 binds to the TAR2 promoter and activates TAR2 expression, thereby promoting nitrate-dependent LR development.
PMID: 33487355
Plant Sci , IF:3.591 , 2021 Feb , V303 : P110750 doi: 10.1016/j.plantsci.2020.110750
Developmental roles of Auxin Binding Protein 1 in Arabidopsis thaliana.
Institute of Science and Technology (IST), Am Campus 1, 3400 Klosterneuburg, Austria.; Laboratoire Reproduction et Developpement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342 Lyon, France; Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic.; Laboratoire Reproduction et Developpement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342 Lyon, France.; Institute of Science and Technology (IST), Am Campus 1, 3400 Klosterneuburg, Austria; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Muthgasse 18, 1190 Vienna, Austria.; Institute of Science and Technology (IST), Am Campus 1, 3400 Klosterneuburg, Austria; Department of Experimental Plant Biology, Faculty of Science, Charles University, Vinicna 5, 12844 Prague, Czech Republic.; Institute of Science and Technology (IST), Am Campus 1, 3400 Klosterneuburg, Austria; Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacky University, Slechtitelu 27, 78371 Olomouc, Czech Republic.; The Czech Academy of Sciences, Institute of Experimental Botany, Rozvojova 263, 165 02 Praha 6, Czech Republic.; Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.; FAFU-Joint Centre, Horticulture and Metabolic Biology Centre, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian, People's Republic of China.; Institute of Science and Technology (IST), Am Campus 1, 3400 Klosterneuburg, Austria. Electronic address: jiri.friml@ist.ac.at.
Auxin is a major plant growth regulator, but current models on auxin perception and signaling cannot explain the whole plethora of auxin effects, in particular those associated with rapid responses. A possible candidate for a component of additional auxin perception mechanisms is the AUXIN BINDING PROTEIN 1 (ABP1), whose function in planta remains unclear. Here we combined expression analysis with gain- and loss-of-function approaches to analyze the role of ABP1 in plant development. ABP1 shows a broad expression largely overlapping with, but not regulated by, transcriptional auxin response activity. Furthermore, ABP1 activity is not essential for the transcriptional auxin signaling. Genetic in planta analysis revealed that abp1 loss-of-function mutants show largely normal development with minor defects in bolting. On the other hand, ABP1 gain-of-function alleles show a broad range of growth and developmental defects, including root and hypocotyl growth and bending, lateral root and leaf development, bolting, as well as response to heat stress. At the cellular level, ABP1 gain-of-function leads to impaired auxin effect on PIN polar distribution and affects BFA-sensitive PIN intracellular aggregation. The gain-of-function analysis suggests a broad, but still mechanistically unclear involvement of ABP1 in plant development, possibly masked in abp1 loss-of-function mutants by a functional redundancy.
PMID: 33487339
Plant Sci , IF:3.591 , 2021 Feb , V303 : P110686 doi: 10.1016/j.plantsci.2020.110686
MiR160 and its target genes ARF10, ARF16 and ARF17 modulate hypocotyl elongation in a light, BRZ, or PAC-dependent manner in Arabidopsis: miR160 promotes hypocotyl elongation.
The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, Shandong, China.; The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, Shandong, China. Electronic address: http0528@163.com.
Multiple hormonal and environmental signals participate in the regulation of plant hypocotyl elongation, which allow the plants to optimize their survival strategy from seed germination to seedling establishment. Auxin plays key roles in cell elongation via auxin signaling transduction and its interactions with other hormonal and environmental signals. However, the roles of auxin response factor (ARF) family in cross-talk between auxin and other hormonal or environmental signals during hypocotyl elongation are not fully understood. Here we show that miR160 and its target genes ARF10, ARF16 and ARF17 modulate hypocotyl elongation in a light, brassinazole (BRZ, a BR biosynthesis inhibitor), or paclobutrazol (PAC, a GA biosynthesis inhibitor)-dependent manner in Arabidopsis. miR160, ARF10, ARF16 and ARF17 have no effects on hypocotyl elongation in the dark. However, in the presence of either light, BRZ, or PAC, ARF10, ARF16 and ARF17 inhibit hypocotyl elongation, and miR160 promotes hypocotyl elongation via cleavage of their mRNA. miR160 and ARF10 are both expressed in the hypocotyl. ARF10 represses the expression of PACLOBUTRAZOL RESISTANCE1 (PRE1) and 35S::PRE1 could partly rescue the phenotype of mARF10 (a miR160-resistant form of ARF10), suggesting that PRE1 acts downstream of ARF10 in regulating hypocotyl elongation. In conclusion, our results indicate that miR160-ARF10/16/17 might serve as a molecular link in cross-talk of auxin, light, BR, and GA in hypocotyl elongation.
PMID: 33487334
J Proteomics , IF:3.509 , 2021 Mar , V236 : P104126 doi: 10.1016/j.jprot.2021.104126
New insight into the rapid growth of the Mikania micrantha stem based on DIA proteomic and RNA-Seq analysis.
School of Life Sciences, Sun Yat-sen University, Xingang Xi Lu 135, Guangzhou 510275, China.; School of Life Sciences, Sun Yat-sen University, Xingang Xi Lu 135, Guangzhou 510275, China; Research Institute of Sun Yat-sen University in Shenzhen, Shenzhen 518057, Shenzhen 518057, China. Electronic address: suyj@mail.sysu.edu.cn.; College of Life Sciences, South China Agricultural University, Wushan 483, Guangzhou 510642, China. Electronic address: tingwang@scau.edu.cn.
Mikania micrantha is one of the world's most invasive plants, which causes severe damage to natural ecosystems and agroforestry systems due to its rapid stem growth. This work investigated the proteomic and transcriptomic profiles of M. micrantha in different stem tissues (pre-internode, post-internode, and internode), as well as in adventitious roots and primary roots with the final goal of elucidating differentially expressed genes and proteins responsible for the rapid growth of stem. The objective was approached by using DIA-based proteomic and RNA-Seq technologies. More than seven giga-transcriptome clean reads were sequenced, and 5196 protein species were identified. Differentially expressed genes identified in all stem tissues were significantly enriched in photosynthesis and carbon fixation, suggesting that the stem possesses a strong photosynthetic capacity in order to maintain the energy supply for this species. Analysis of differentially expressed proteins showed that proteins related to photosystem I/II and the cytochrome b6/f complex, such as D1, D2, and cp43, were also highly accumulated in the adventitious roots, corroborating the transcriptome analysis results. These results provided basic proteomic and transcriptional expression information about the M. micrantha stem and adventitious root, thereby improving our understanding of the molecular mechanism underlying rapid growth in this species. SIGNIFICANCE: This is the first study to investigate the proteomic and transcriptomic profiles of Mikania micrantha, a highly invasive plant, in different stem tissues (pre-internode, post-internode, and internode), as well as in adventitious and primary roots, using the latest DIA-based (data-independent acquisition mode) proteomic and RNA-Seq technologies. A comprehensive study was carried out, and differentially expressed genes and differentially expressed proteins identified in the pre-internode, post-internode, and internode tissues were significantly enriched during photosynthesis and carbon fixation, suggesting that the M. micrantha stem possesses a strong photosynthetic capacity that allows the plant to maintain a high energy supply. Enriched plant hormone signal transduction pathway analysis revealed an interaction between auxin and other phytohormones involved in adventitious root development. The study provided basic data on the molecular mechanism of M. micrantha vegetative propagation and the rapid growth of its stem. The novel scientific content of this study successfully builds upon the limited information currently available on the subject, therefore warranting publication.
PMID: 33540067
BMC Plant Biol , IF:3.497 , 2021 Feb , V21 (1) : P111 doi: 10.1186/s12870-021-02828-7
Elucidation of molecular and hormonal background of early growth cessation and endodormancy induction in two contrasting Populus hybrid cultivars.
Department of Plant Molecular Biology, Agricultural Institute, Centre for Agricultural Research, ELKH, Martonvasar, H-2462, Hungary.; Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada.; Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, 165 02, Czech Republic.; Department of Plant Molecular Biology, Agricultural Institute, Centre for Agricultural Research, ELKH, Martonvasar, H-2462, Hungary. galiba.gabor@atk.hu.; Festetics Doctoral School, Georgikon Campus, Szent Istvan University, Keszthely, H-8360, Hungary. galiba.gabor@atk.hu.
BACKGROUND: Over the life cycle of perennial trees, the dormant state enables the avoidance of abiotic stress conditions. The growth cycle can be partitioned into induction, maintenance and release and is controlled by complex interactions between many endogenous and environmental factors. While phytohormones have long been linked with dormancy, there is increasing evidence of regulation by DAM and CBF genes. To reveal whether the expression kinetics of CBFs and their target PtDAM1 is related to growth cessation and endodormancy induction in Populus, two hybrid poplar cultivars were studied which had known differential responses to dormancy inducing conditions. RESULTS: Growth cessation, dormancy status and expression of six PtCBFs and PtDAM1 were analyzed. The 'Okanese' hybrid cultivar ceased growth rapidly, was able to reach endodormancy, and exhibited a significant increase of several PtCBF transcripts in the buds on the 10th day. The 'Walker' cultivar had delayed growth cessation, was unable to enter endodormancy, and showed much lower CBF expression in buds. Expression of PtDAM1 peaked on the 10th day only in the buds of 'Okanese'. In addition, PtDAM1 was not expressed in the leaves of either cultivar while leaf CBFs expression pattern was several fold higher in 'Walker', peaking at day 1. Leaf phytohormones in both cultivars followed similar profiles during growth cessation but differentiated based on cytokinins which were largely reduced, while the Ox-IAA and iP7G increased in 'Okanese' compared to 'Walker'. Surprisingly, ABA concentration was reduced in leaves of both cultivars. However, the metabolic deactivation product of ABA, phaseic acid, exhibited an early peak on the first day in 'Okanese'. CONCLUSIONS: Our results indicate that PtCBFs and PtDAM1 have differential kinetics and spatial localization which may be related to early growth cessation and endodormancy induction under the regime of low night temperature and short photoperiod in poplar. Unlike buds, PtCBFs and PtDAM1 expression levels in leaves were not associated with early growth cessation and dormancy induction under these conditions. Our study provides new evidence that the degradation of auxin and cytokinins in leaves may be an important regulatory point in a CBF-DAM induced endodormancy. Further investigation of other PtDAMs in bud tissue and a study of both growth-inhibiting and the degradation of growth-promoting phytohormones is warranted.
PMID: 33627081
BMC Plant Biol , IF:3.497 , 2021 Feb , V21 (1) : P98 doi: 10.1186/s12870-021-02877-y
Integrated metabolic profiling and transcriptome analysis of pigment accumulation in Lonicera japonica flower petals during colour-transition.
Key Laboratory of Horticulture Science for Southern Mountains Regions of Ministry of Education; College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, China.; Academy of Agricultural Sciences of Southwest University, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Chongqing, 400715, China.; Henan International Joint Laboratory of Crop Gene Resources and Improvement, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China.; Rare Plant Research Institute of the Yangtze River (Yichang); Institute of Science and Technology, China Three Gorges Corporation, Beijing, 100083, China.; Key Laboratory of Horticulture Science for Southern Mountains Regions of Ministry of Education; College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, China. qgguo@126.com.; Academy of Agricultural Sciences of Southwest University, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Chongqing, 400715, China. qgguo@126.com.; Key Laboratory of Horticulture Science for Southern Mountains Regions of Ministry of Education; College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, China. lianggl@swu.edu.cn.; Academy of Agricultural Sciences of Southwest University, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Chongqing, 400715, China. lianggl@swu.edu.cn.
BACKGROUND: Plants have remarkable diversity in petal colour through the biosynthesis and accumulation of various pigments. To better understand the mechanisms regulating petal pigmentation in Lonicera japonica, we used multiple approaches to investigate the changes in carotenoids, anthocyanins, endogenous hormones and gene expression dynamics during petal colour transitions, i.e., green bud petals (GB_Pe), white flower petals (WF_Pe) and yellow flower petals (YF_Pe). RESULTS: Metabolome analysis showed that YF_Pe contained a much higher content of carotenoids than GB_Pe and WF_Pe, with alpha-carotene, zeaxanthin, violaxanthin and gamma-carotene identified as the major carotenoid compounds in YF_Pe. Comparative transcriptome analysis revealed that the key differentially expressed genes (DEGs) involved in carotenoid biosynthesis, such as phytoene synthase, phytoene desaturase and zeta-carotene desaturase, were significantly upregulated in YF_Pe. The results indicated that upregulated carotenoid concentrations and carotenoid biosynthesis-related genes predominantly promote colour transition. Meanwhile, two anthocyanins (pelargonidin and cyanidin) were significantly increased in YF_Pe, and the expression level of an anthocyanidin synthase gene was significantly upregulated, suggesting that anthocyanins may contribute to vivid yellow colour in YF_Pe. Furthermore, analyses of changes in indoleacetic acid, zeatin riboside, gibberellic acid, brassinosteroid (BR), methyl jasmonate and abscisic acid (ABA) levels indicated that colour transitions are regulated by endogenous hormones. The DEGs involved in the auxin, cytokinin, gibberellin, BR, jasmonic acid and ABA signalling pathways were enriched and associated with petal colour transitions. CONCLUSION: Our results provide global insight into the pigment accumulation and the regulatory mechanisms underlying petal colour transitions during the flower development process in L. japonica.
PMID: 33596836
Planta , IF:3.39 , 2021 Feb , V253 (2) : P59 doi: 10.1007/s00425-021-03568-6
Identification of microRNAs and their gene targets in cytoplasmic male sterile and fertile maintainer lines of pigeonpea.
ICAR-Indian Institute of Pulses Research (IIPR), Kanpur, India. abhi.omics@gmail.com.; International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, India.; Hyderabad Central University (HCU), Hyderabad, India.; ICAR-Indian Institute of Pulses Research (IIPR), Kanpur, India.
MAIN CONCLUSION: Comparative analysis of genome-wide miRNAs and their gene targets between cytoplasmic male sterile (CMS) and fertile lines of pigeonpea suggests a possible role of miRNA-regulated pathways in reproductive development. Exploitation of hybrid vigor using CMS technology has delivered nearly 50% yield gain in pigeonpea. Among various sterility-inducing cytoplasms (A1-A9) reported so far in pigeonpea, A2 and A4 are the two major sources that facilitate hybrid seed production. Recent evidence suggests involvement of micro RNA in vast array of biological processes including plant reproductive development. In pigeonpea, information about the miRNAs is insufficient. In view of this, we sequenced six small RNA libraries of CMS line UPAS 120A and isogenic fertile line UPAS 120B using Illumina technology. Results revealed 316 miRNAs including 248 known and 68 novel types. A total of 637 gene targets were predicted for known miRNAs, while 324 genes were associated with novel miRNAs. Degradome analysis revealed 77 gene targets of predicted miRNAs, which included a variety of transcription factors playing key roles in plant reproduction such as F-box family proteins, apetala 2, auxin response factors, ethylene-responsive factors, homeodomain-leucine zipper proteins etc. Differential expression of both known and novel miRNAs implied roles for both conserved as well as species-specific players. We also obtained several miRNA families such as miR156, miR159, miR167 that are known to influence crucial aspects of plant fertility. Gene ontology and pathway level analyses of the target genes showed their possible implications for crucial events during male reproductive development such as tapetal degeneration, pollen wall formation, retrograde signaling etc. To the best of our knowledge, present study is first to combine deep sequencing of small RNA and degradome for elucidating the role of miRNAs in flower and male reproductive development in pigeonpea.
PMID: 33538916
Planta , IF:3.39 , 2021 Feb , V253 (2) : P54 doi: 10.1007/s00425-021-03571-x
Are sesquiterpene lactones the elusive KARRIKIN-INSENSITIVE2 ligand?
Plant Hormone Biology Group, Green Life Sciences Cluster, Swammerdam Institute for Life Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.; Plant Hormone Biology Group, Green Life Sciences Cluster, Swammerdam Institute for Life Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands. h.j.bouwmeester@uva.nl.
MAIN CONCLUSION: The sunflower sesquiterpene lactones 8-epixanthatin and tomentosin can bind to the hydrophobic pocket of sunflower KAI2 with an affinity much higher than for the exogenous ligand KAR. Sesquiterpene lactones (STLs) are secondary plant metabolites with a wide range of biological, such as anti-microbial, activities. Intriguingly, the STLs have also been implicated in plant development: in several Asteraceae, STL levels correlate with the photo-inhibition of hypocotyl elongation. Although this effect was suggested to be due to auxin transport inhibition, there is no structural-functional evidence for this claim. Intriguingly, the light-induced inhibition of hypocotyl elongation in Arabidopsis has been ascribed to HYPOSENSITIVE TO LIGHT/KARRIKIN-INSENSITIVE2 (HTL/KAI2) signaling. KAI2 was discovered because of its affinity to the smoke-derived karrikin (KAR), though it is generally assumed that KAI2 has another, endogenous but so far elusive, ligand rather than the exogenous KARs. Here, we postulate that the effect of STLs on hypocotyl elongation is mediated through KAI2 signaling. To support this hypothesis, we have generated homology models of the sunflower KAI2s (HaKAI2s) and used them for molecular docking studies with STLs. Our results show that particularly two sunflower STLs, 8-epixanthatin and tomentosin, can bind to the hydrophobic pockets of HaKAI2s with high affinity. Our results are in line with a recent study, showing that these two STLs accumulate in the light-exposed hypocotyls of sunflower. This finding sheds light on the effect of STLs in hypocotyl elongation that has been reported for many decades but without conclusive insight in the elusive mechanism underlying this effect.
PMID: 33521891
Plant Mol Biol , IF:3.302 , 2021 Feb doi: 10.1007/s11103-021-01126-y
Fundamental mechanisms of the stem cell regulation in land plants: lesson from shoot apical cells in bryophytes.
Graduate School of Life Sciences, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, 980-8577, Japan.; Graduate School of Life Sciences, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, 980-8577, Japan. junko.kyozuka.e4@tohoku.ac.jp.
KEY MESSAGE: This review compares the molecular mechanisms of stem cell control in the shoot apical meristems of mosses and angiosperms and reveals the conserved features and evolution of plant stem cells. The establishment and maintenance of pluripotent stem cells in the shoot apical meristem (SAM) are key developmental processes in land plants including the most basal, bryophytes. Bryophytes, such as Physcomitrium (Physcomitrella) patens and Marchantia polymorpha, are emerging as attractive model species to study the conserved features and evolutionary processes in the mechanisms controlling stem cells. Recent studies using these model bryophyte species have started to uncover the similarities and differences in stem cell regulation between bryophytes and angiosperms. In this review, we summarize findings on stem cell function and its regulation focusing on different aspects including hormonal, genetic, and epigenetic control. Stem cell regulation through auxin, cytokinin, CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) signaling and chromatin modification by Polycomb Repressive Complex 2 (PRC2) and PRC1 is well conserved. Several transcription factors crucial for SAM regulation in angiosperms are not involved in the regulation of the SAM in mosses, but similarities also exist. These findings provide insights into the evolutionary trajectory of the SAM and the fundamental mechanisms involved in stem cell regulation that are conserved across land plants.
PMID: 33609252
Plant Mol Biol , IF:3.302 , 2021 Feb , V105 (3) : P263-285 doi: 10.1007/s11103-020-01086-9
Bulk RNA-Seq analysis to dissect the regulation of stigma position in tomato.
Department of Agriculture and Forest Sciences, University of Tuscia, Via S.C. de Lellis snc, 01100, Viterbo, Italy.; Department of Agriculture and Forest Sciences, University of Tuscia, Via S.C. de Lellis snc, 01100, Viterbo, Italy. mazz@unitus.it.
KEY MESSAGE: Transcriptomic analysis of tomato genotypes contrasting for stigma position suggests that stigma insertion occurred by the disruption of a process that finds a parallel in Arabidopsis gynoecium development. Domestication of cultivated tomato (Solanum lycopersicum L.) included the transition from allogamy to autogamy that occurred through the loss of self-incompatibilty and the retraction of the stigma within the antheridial cone. Although the inserted stigma is an established phenotype in modern tomatoes, an exserted stigma is still present in several landraces or vintage varieties. Moreover, exsertion of the stigma is a frequent response to high temperature stress and, being a cause of reduced fertility, a trait of increasing importance. Few QTLs for stigma position have been described and only one of the underlying genes identified. To gain insights on genes involved in stigma position in tomato, a bulk RNA sequencing (RNA-Seq) approach was adopted, using two groups of contrasting genotypes. Phenotypic analysis confirmed the extent and the stability of stigma position in the selected genotypes, whereas they were highly heterogeneous for other reproductive and productive traits. The RNA-Seq analysis yielded 801 differentially expressed genes (DEGs), 566 up-regulated and 235 down-regulated in the genotypes with exserted stigma. Validation by quantitative PCR indicated a high reliability of the RNA-Seq data. Up-regulated DEGs were enriched for genes involved in the cell wall metabolism, lipid transport, auxin response and flavonoid biosynthesis. Down-regulated DEGs were enriched for genes involved in translation. Validation of selected genes on pistil tissue of the 26 single genotypes revealed that differences between bulks could both be due to a general trend of the bulk or to the behaviour of single genotypes. Novel candidate genes potentially involved in the control of stigma position in tomato are discussed.
PMID: 33104942
Environ Sci Pollut Res Int , IF:3.056 , 2021 Feb , V28 (5) : P5704-5713 doi: 10.1007/s11356-020-10851-8
Lead (Pb)-resistant bacteria inhibit Pb accumulation in dill (Anethum graveolens L.) by improving biochemical, physiological, and antioxidant enzyme response of plants.
Department of Horticulture, Faculty of Agricultural Sciences and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran.; Department of Horticulture, Faculty of Agricultural Sciences and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran. behsmaiel@yahoo.com.; Department of Environmental Sciences and Engineering, Government College University, Faisalabad, Pakistan.; Department of Soil Science, Faculty of Agricultural Sciences and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran.
The accumulation of heavy metal in the soil is a serious concern for sustainable food production due to their toxic effects on plants and other living things. The strategies are required on urgent bases for the management of metal-contaminated soils. Thus, the microbes from the genus Pseudomonas were characterized for different traits and lead (Pb)-resistant ability and their effects were assessed on growth, photosynthesis, antioxidant capacity, and Pb uptake by dill (Anethum graveolens L.). Furthermore, soil basal respiration and induced respiration in soil were also assessed under microbes and Pb stress. Among the tested three strains, Pseudomonas P159 and P150 were more tolerant to Pb stress than Pseudomonas P10, whereas P159 showed the highest values for phosphorus (P), siderophore, auxin, and hydrogen cyanide production. The bacterial inoculation increased the plant shoot dry weights, carbohydrates, proline, and chlorophyll contents under Pb stress. The catalase (CAT) and peroxidase (POD) activities of the plants were higher in bacterial-treated plants than control. The bacterial inoculation decreased Pb concentration in plants, and the response varied with the type of microbes. The bacterial strains enhanced the soil basal and induced respiration than respective Pb treatments alone. Overall, Pseudomonas P159 is potentially suitable for the remediation of Pb-contaminated soils. Graphical abstract.
PMID: 32968907
J Plant Physiol , IF:3.013 , 2021 Feb , V257 : P153343 doi: 10.1016/j.jplph.2020.153343
Growth promotion in Arabidopsis thaliana by bacterial cyclodipeptides involves the TOR/S6K pathway activation.
Instituto de Investigaciones Quimico Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Ed B1, B3, A1', U3, Ciudad Universitaria, Morelia, Michoacan, CP 58030, Mexico.; Instituto de Investigaciones Quimico Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Ed B1, B3, A1', U3, Ciudad Universitaria, Morelia, Michoacan, CP 58030, Mexico. Electronic address: delacruz@umich.mx.
Cyclodipeptides (CDPs) are the smallest peptidic molecules that can be produced by diverse organisms such as bacteria, fungi, and animals. They have multiple biological effects. In this paper, we examined the CDPs produced by the bacteria Pseudomonas aeruginosa PAO1, which are known as opportunistic pathogens of humans and plants on TARGET OF RAPAMYCIN (TOR) signaling pathways, and regulation of root system architecture. This bacterium produces the bioactive CDPs: cyclo(L-Pro-L-Leu), cyclo(L-Pro-L-Phe), cyclo(L-Pro-L-Tyr), and cyclo(L-Pro-L-Val). In a previous report, these molecules were found to modulate basic cellular programs not only via auxin mechanisms but also by promoting the phosphorylation of the S6 ribosomal protein kinase (S6K), a downstream substrate of the TOR kinase. In the present work, we found that the inoculation of Arabidopsis plants with P. aeruginosa PAO1, the non-pathogenic P. aeruginosa DeltalasI/Deltarhll strain (JM2), or by direct exposure of plants to CDPs influenced growth and promoted root branching depending upon the treatment imposed, while genetic evidence using Arabidopsis lines with enhanced or decreased TOR levels indicated a critical role of this pathway in the bacterial phytostimulation.
PMID: 33387853
Gene , IF:2.984 , 2021 Feb , V768 : P145302 doi: 10.1016/j.gene.2020.145302
Genome-wide characterization and expression analyses of the auxin/indole-3-acetic acid (Aux/IAA) gene family in apple (Malus domestica).
Department of Horticulture, Gansu Agricultural University, Lanzhou 730000, China.; Department of Horticulture, Gansu Agricultural University, Lanzhou 730000, China. Electronic address: bhch@gsau.edu.cn.
Auxin is a necessary phytohormone for fruit development, accompanying the whole process of fruit growth and development. The Aux/IAA gene family is one of the early auxin-responsive gene families. At present, there were few reports involved in Aux/IAA genes in the fruit, especially in apple. In our study, we identified 42 MdAux/IAAs, phylogenetic analysis showed that Aux/IAA proteins from apple, tomato, and strawberry were clustered into 5 groups, 42 MdAux/IAAs randomly distributed on 13 chromosomes. Additionally, a comprehensive analysis of Aux/IAA gene family was completed, including gene structures, conserved motifs, phylogenetic analysis, chromosome mapping, orthologous identification, selection pressure analyses, synteny analysis, and protein interaction. We also tested the expression of MdAux/IAAs in different tissues and fruit development stages using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), we found that the most members of Aux/IAA showed higher expression in seeds compared within stem and leaves, indicating they may play a role in regulating fruit development. We also declared that the expression of Aux/IAA gene was not consistent in the pericarp and seeds at the same developmental stage, 3 MdAux/IAAs of the pericarp were upregulated over 20-fold at 90 d and 5 MdAux/IAAs of the seeds were upregulated over 40-fold at 90 d. It was MdAux/IAA23 that showed extreme up-regulated expression in both pericarp and seeds. This study proved that the Aux/IAA gene families may perform a different function in apple fruit development and ripening, more importantly, it provided a foundation for further exploring the biological function of these MdAux/IAAs.
PMID: 33181252
PLoS One , IF:2.74 , 2021 , V16 (2) : Pe0247666 doi: 10.1371/journal.pone.0247666
A novel micropropagation of Lycium ruthenicum and epigenetic fidelity assessment of three types of micropropagated plants in vitro and ex vitro.
Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang, Liaoning, China.
Lycium ruthenicum is an excellent eco-economic shrub. Numerous researches have been conducted for the function of its fruits but scarcely focused on the somaclonal variation and DNA methylation. An efficient micropropagation protocol from leaves and stems of L. ruthenicum was developed in this study, in which not only the leaf explants but also the stem explants of L. ruthenicum were dedifferentiated and produced adventitious buds/multiple shoots on one type of medium. Notably, the efficient indirect organogenesis of stem explants was independent of exogenous auxin, which is contrary to the common conclusion that induction and proliferation of calli is dependent on exogenous auxin. We proposed that sucrose supply might be the crucial regulator of stem callus induction and proliferation of L. ruthenicum. Furthermore, results of methylation-sensitive amplified polymorphism (MSAP) showed that DNA methylation somaclonal variation (MSV) of CNG decreased but that of CG increased after acclimatization. Three types of micropropagated plants (from leaf calli, stem calli and axillary buds) were epigenetically diverged more from each other after acclimatization and the ex vitro micropropagated plants should be selected to determine the fidelity. In summary, plants micropropagated from axillary buds and leaves of L. ruthenicum was more fidelity and might be suitable for preservation and propagation of elite germplasm. Also, leaf explants should be used in transformation. Meanwhile, plants from stem calli showed the highest MSV and might be used in somaclonal variation breeding. Moreover, one MSV hotspot was found based on biological replicates. The study not only provided foundations for molecular breeding, somaclonal variation breeding, preservation and propagation of elite germplasm, but also offered clues for further revealing novel mechanisms of both stem-explant dedifferentiation and MSV of L. ruthenicum.
PMID: 33621255
PLoS One , IF:2.74 , 2021 , V16 (2) : Pe0246971 doi: 10.1371/journal.pone.0246971
High efficient de novo root-to-shoot organogenesis in Citrus jambhiri Lush.: Gene expression, genetic stability and virus indexing.
ICAR Research Complex for North Eastern Hill Region, Imphal, Manipur, India.; Institute of Agriculture, Visva-Bharati, Sriniketan, West Bengal, India.
A protocol for high-frequency direct organogenesis from root explants of Kachai lemon (Citrus jambhiri Lush.) was developed. Full-length roots (~3 cm) were isolated from the in vitro grown seedlings and cultured on Murashige and Skoog basal medium supplemented with Nitsch vitamin (MSN) with different concentrations of cytokinin [6-benzylaminopurine, (BAP)] and gibberellic acid (GA3). The frequency of multiple shoot proliferation was very high, with an average of 34.3 shoots per root explant when inoculated on the MSN medium supplemented with BAP (1.0 mg L-1) and GA3 (1.0 mg L-1). Optimal rooting was induced in the plantlets under half strength MSN medium supplemented with indole-3-acetic acid (IAA, 0.5-1.0 mg L-1). IAA induced better root structure than 1-naphthaleneacetic acid (NAA), which was evident from the scanning electron microscopy (SEM). The expressions of growth regulating factor genes (GRF1 and GRF5) and GA3 signaling genes (GA2OX1 and KO1) were elevated in the regenerants obtained from MSN+BAP (1.0 mg L-1)+GA3 (1.0 mg L-1). The expressions of auxin regulating genes were high in roots obtained in (1/2) MSN+IAA 1.0 mg L-1. Furthermore, indexing of the regenerants confirmed that there was no amplicons detected for Huanglongbing bacterium and Citrus tristeza virus. Random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) markers detected no polymorphic bands amongst the regenerated plants. This is the first report that describes direct organogenesis from the root explant of Citrus jambhiri Lush. The high-frequency direct regeneration protocol in the present study provides an enormous significance in Citrus organogenesis, its commercial cultivation and genetic conservation.
PMID: 33606806
Funct Plant Biol , IF:2.617 , 2021 Feb , V48 (3) : P241-256 doi: 10.1071/FP20253
Transcriptome profiling to identify tepal cell enlargement and pigmentation genes and the function of LtEXLB1 in Lilium tsingtauense.
College of Landscape Architecture and Forestry, Qingdao Agricultural University, 700 Changcheng Road, ChengYang District, Qingdao 266109, PR China.; College of Landscape Architecture and Forestry, Qingdao Agricultural University, 700 Changcheng Road, ChengYang District, Qingdao 266109, PR China; and Corresponding author. Email: horticultural8@163.com.
To understand the molecular mechanism underlying tepal development and pigmentation in Lilium tsingtauense Gilg, we performed whole-transcriptome profiles from closed buds at the greenish tepal stage (CBS), the full-bloom with un-horizontal tepal stage (UFS), and the completely opened bud with reflected tepal stage (RFS) of L. tsingtauense. More than 95699 transcripts were generated using a de novo assembly approach. Gene ontology and pathway analysis of the assembled transcripts revealed carbon metabolism is involved in tepal development and pigmentation. In total, 8171 differentially expression genes (DEGs) in three tepal stages were identified. Among these DEGs, ~994 genes putatively encoded transcription factors (TFs), whereas 693 putatively encoded protein kinases. Regarding hormone pathways, 51 DEGs involved in auxin biosynthesis and signalling and 10 DEGs involved in ethylene biosynthesis and signalling. We also isolated seven LtEXPANSINs, including four EXPAs, one EXPB, one EXLA and one EXLB. LtEXLB1 (GenBank: MN856627) was expressed at higher levels in UFS and RFS, compared with CBS. Silencing LtEXLB1 in leaf discs and tepals by virus-induced gene silencing significantly decreased cell expansion under rehydration conditions. Further analysis revealed that more cell numbers were existed in the abaxial and adaxial subepidermis in the silenced LtEXLB1 samples. As the first transcriptome of L. tsingtauense, the unigenes are a valuable resource for future studies on tepal development, and LtEXLB1 functions in cell expansion.
PMID: 33059816
J Plant Res , IF:2.185 , 2021 Feb doi: 10.1007/s10265-021-01261-z
Promotion of auxin- and gibberellin-induced elongation of epicotyl segments of Vigna angularis by short-chain carboxylic acids.
Institute of Biological Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8572, Japan. satoh.shinobu.ga@u.tsukuba.ac.jp.; Biological Institute, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama, 236-0027, Japan. satoh.shinobu.ga@u.tsukuba.ac.jp.
Pollen tube growth is inhibited and promoted by long- and short-chain carboxylic acids, respectively, but is not affected by formic acid. For auxin- and gibberellin-induced elongation of in vitro cultured epicotyl segments of adzuki bean (Vigna angularis), a series of carboxylic acids showed similar effects as that on pollen tube growth except that formic acid showed the strongest promotive effect. The effects of formic acid and GA3 on IAA-induced elongation were additive and both were strongly inhibited by inhibitors of cellulose synthesis (coumarin) and microtubule formation (colchicine). Formic acid, possibly by incorporation into the segments, prolonged the promotion by IAA and GA3 of the elongation of epicotyl segments. Based on these results and later advances in our understanding of metabolism and the role of formic acid in protecting against oxidative stress, a possible role of formic acid on stem elongation is discussed.
PMID: 33559785
J Plant Res , IF:2.185 , 2021 Feb doi: 10.1007/s10265-020-01247-3
Phyllotaxis: from classical knowledge to molecular genetics.
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033, Japan. yinx@bs.s.u-tokyo.ac.jp.; Japan Society for the Promotion of Science, Tokyo, Japan. yinx@bs.s.u-tokyo.ac.jp.
Plant organs are repetitively generated at the shoot apical meristem (SAM) in recognizable patterns. This phenomenon, known as phyllotaxis, has long fascinated scientists from different disciplines. While we have an enriched body of knowledge on phyllotactic patterns, parameters, and transitions, only in the past 20 years, however, have we started to identify genes and elucidate genetic pathways that involved in phyllotaxis. In this review, I first summarize the classical knowledge of phyllotaxis from a morphological perspective. I then discuss recent advances in the regulation of phyllotaxis, from a molecular genetics perspective. I show that the morphological beauty of phyllotaxis we appreciate is the manifestation of many regulators, in addition to the critical role of auxin as a patterning signal, exerting their respective effects in a coordinated fashion either directly or indirectly in the SAM.
PMID: 33550488
J Plant Res , IF:2.185 , 2021 Feb doi: 10.1007/s10265-021-01253-z
Repatterning of the inflorescence meristem in Gerbera hybrida after wounding.
Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, P.O.Box 27, 00014, Helsinki, Finland.; Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, P.O.Box 27, 00014, Helsinki, Finland. paula.elomaa@helsinki.fi.
The Asteraceae plant family is characterized by inflorescences, called flower heads or capitula that may combine hundreds of individual florets into a single flower-like structure. The florets are arranged in a regular phyllotactic pattern with Fibonacci numbers of left- and right-winding spirals. Such a pattern may be disrupted due to physical constraints or by wounding occurring during the early meristem development. Recovery from wounding re-establishes patterning although the mechanisms have remained elusive. In this study, we applied Gerbera hybrida as a model system and established methods to conduct wounding experiments either with syringe needles or using laser ablation combined with live imaging of head meristems. By revisiting the historical experiments in sunflower, we conducted wounding to transgenic auxin reporter lines of gerbera and followed the recovery of cellular growth and meristem patterning. We show that wounding disrupted the expression of the gerbera CLAVATA3 (GhCLV3) gene that marks the undifferentiated meristematic region and led to de novo re-initiation of patterning at the wound margin. During the recovery growth, three to five layers of elongated cells showing periclinal cell division planes and lacking auxin signal were formed at the wound rim. DR5 auxin signal was shown to localize and form regularly spaced maxima in a distance from the wound rim. Consequently, spiral pattern of contact parastichies was re-established by stacking of new auxin maxima on top of the previous ones. The developed methods facilitate future studies on understanding the molecular mechanisms of de novo patterning of meristems.
PMID: 33543368
Biol Open , IF:2.029 , 2021 Feb , V10 (2) doi: 10.1242/bio.057992
Auxin confers protection against ER stress in Caenorhabditis elegans.
Laboratory of Biology and Modelling of the Cell, Ecole Normale Superieure de Lyon, CNRS UMR5239, INSERM U1210, Universite de Lyon, 69007 Lyon, France.; Laboratory of Biology and Modelling of the Cell, Ecole Normale Superieure de Lyon, CNRS UMR5239, INSERM U1210, Universite de Lyon, 69007 Lyon, France paola.fabrizio@ens-lyon.fr.
Auxins are plant growth regulators that influence most aspects of plant development through complex mechanisms. The development of an auxin-inducible degradation (AID) system has enabled rapid, conditional protein depletion in yeast and cultured cells. More recently, the system was successfully adapted to C aenorhabditis elegans to achieve auxin-dependent degradation of targets in all tissues and developmental stages. Whether auxin treatment alone has an impact on nematode physiology is an open question. Here we show that indole-3-acetic acid (IAA), the auxin most commonly used to trigger AID in worms, functions through the conserved IRE-1/XBP-1 branch of the Unfolded Protein Response (UPR) to promote resistance to endoplasmic reticulum (ER) stress. Because the UPR not only plays a central role in restoring ER homeostasis, but also promotes lipid biosynthesis and regulates lifespan, we suggest that extreme caution should be exercised when using the AID system to study these and related processes.
PMID: 33495210
Physiol Mol Biol Plants , IF:2.005 , 2021 Jan , V27 (1) : P69-80 doi: 10.1007/s12298-021-00929-z
Comparative analysis of transcriptomic profiling to identify genes involved in the bulged surface of pear fruit (Pyrus bretschneideri Rehd. cv. Yuluxiangli).
College of Forestry, Shanxi Agricultural University, Taigu, 030801 Shanxi China.grid.412545.30000 0004 1798 1300; College of Horticulture, Shanxi Agricultural University, Taigu, 030801 Shanxi China.grid.412545.30000 0004 1798 1300
Pear (Pyrus spp.) belongs to the genus Pyrus, in the family Rosaceae. Some varieties of pear fruit exhibit bulged surface, which seriously affects the quality and commodity value of the pear fruit. In this study, we performed anatomical, physiological, and transcriptomic analysis to explore the mechanism of paclobutrazol (PBZ) on the bulged surface of pear fruit. The vascular bundles of flesh were more evenly distributed, and the fruit cells were more compactly arranged and smaller in size treated with PBZ. However, the auxin (IAA) content of flesh was decreased in the treated group. Furthermore, the GO and KEGG analysis of differentially expressed genes (DEGs) showed that auxin, phenylpropanoid metabolic pathways, and transcriptional factor genes were significantly enriched on the relieved bulged surface of pear fruit. And it was analyzed that some genes contained auxin responded cis-elements from the selected DEGs in the promoter region. We conclude that PBZ plays a negative role in cell division, cell elongation, and vascular bundle development on the bulged surface of pear fruit through the involvement of auxin-related genes. This study will provide a theoretical basis for the regulation of the bulged surface of pear fruit by a growth retardant agent. Supplementary information: The online version of this article (10.1007/s12298-021-00929-z) contains supplementary material, which is available to authorized users.
PMID: 33627963
J Econ Entomol , IF:1.938 , 2021 Feb doi: 10.1093/jee/toab009
Buzz-Pollinated Crops: A Global Review and Meta-analysis of the Effects of Supplemental Bee Pollination in Tomato.
Department of Biological and Environmental Sciences, University of Stirling. Stirling, Scotland, UK.; School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK.
Buzz-pollinated plants require visitation from vibration producing bee species to elicit full pollen release. Several important food crops are buzz-pollinated including tomato, eggplant, kiwi, and blueberry. Although more than half of all bee species can buzz pollinate, the most commonly deployed supplemental pollinator, Apis mellifera L. (Hymenoptera: Apidae; honey bees), cannot produce vibrations to remove pollen. Here, we provide a list of buzz-pollinated food crops and discuss the extent to which they rely on pollination by vibration-producing bees. We then use the most commonly cultivated of these crops, the tomato, Solanum lycopersicum L. (Solanales: Solanaceae), as a case study to investigate the effect of different pollination treatments on aspects of fruit quality. Following a systematic review of the literature, we statistically analyzed 71 experiments from 24 studies across different geopolitical regions and conducted a meta-analysis on a subset of 21 of these experiments. Our results show that both supplemental pollination by buzz-pollinating bees and open pollination by assemblages of bees, which include buzz pollinators, significantly increase tomato fruit weight compared to a no-pollination control. In contrast, auxin treatment, artificial mechanical vibrations, or supplemental pollination by non-buzz-pollinating bees (including Apis spp.), do not significantly increase fruit weight. Finally, we compare strategies for providing bee pollination in tomato cultivation around the globe and highlight how using buzz-pollinating bees might improve tomato yield, particularly in some geographic regions. We conclude that employing native, wild buzz pollinators can deliver important economic benefits with reduced environmental risks and increased advantages for both developed and emerging economies.
PMID: 33615362
C R Biol , IF:1.904 , 2021 Feb , V343 (3) : P257-265 doi: 10.5802/crbiol.23
The root response to gravity: from the macro to the nanoscale.
Laboratoire Reproduction et Developpement des Plantes, Universite de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342 Lyon, France.; Plant Biology Laboratory, Salk Institute for Biological Studies, 10010 N Torrey Pines Rd, La Jolla, CA 92037, USA.
Plants are sessile organisms which adapt to their everchanging environment. The root is buried is the soil and continuously explores its surroundings. Indeed, while growing downwards to anchor the plants in the ground, it has to avoid obstacles and seek for nutrients and water. This seeking mechanism depends on the root perception of gravity. Through differential growth, the root is able to align according to the gravity vector. The growth is regulated at the cellular level by an increase of the plant hormone auxin, which activates the small Rho Guanine triphosphatase (Rho GTPase) of plant 6 (ROP6) at the plasma membrane to inhibit endocytosis and trigger cytoskeleton reorganization. Through a collaborative work, four French laboratories addressed the question of ROP6 membrane dynamics upon gravistimulation. Based on cellular biology, biochemistry and super resolution imaging approaches, they discovered that ROP6 is organized into nanoclusters at the plasma membrane of plant cells in response to auxin. The stabilization of ROP6 in these nanoclusters is required for signaling and thus the regulation of gravitropic bending. The formation of these nanoclusters is dependent upon the membrane lipid phosphatidylserine, which directly interact with ROP6. Using a genetic toolkit, the authors uncovered that phosphatidylserine is rate limiting for the ROP6-dependent nanocluster formation, which in turn tunes the cellular read outs. This work, not only explain the fine mechanism of the root response to gravity from the developmental level to the nanoscale but also provide a valuable insight towards the understanding of small GTPase signaling in eukaryotic system.
PMID: 33621455
Plant Signal Behav , IF:1.671 , 2021 Feb : P1885888 doi: 10.1080/15592324.2021.1885888
The role of auxin in nitrogen-modulated shoot branching.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University , Nanjing, China.; Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences , Shenzhen, China.
Shoot branching is determined by axillary bud formation and outgrowth and remains one of the most variable determinants of yield in many crops. Plant nitrogen (N) acquired mainly in the forms of nitrate and ammonium from soil, dominates plant development, and high-yield crop production relies heavily on N fertilization. In this review, the regulation of axillary bud outgrowth by N availability and forms is summarized in plant species. The mechanisms of auxin function in this process have been well characterized and reviewed, while recent literature has highlighted that auxin export from a bud plays a critical role in N-modulating this process.
PMID: 33570443
Plant Signal Behav , IF:1.671 , 2021 Feb : P1879532 doi: 10.1080/15592324.2021.1879532
Arabidopsis MYB28 and MYB29 transcription factors are involved in ammonium-mediated alterations of root-system architecture.
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU) , Bilbao, Spain.; Ikerbasque, Basque Foundation for Science , Bilbao, Spain.
Ammonium (NH4 (+)) is known to produce alterations in root-system architecture, notably, by inhibiting primary root elongation and stimulating lateral root branching. This stimulation is associated with higher auxin transport promoted by apoplast acidification. Recently, we showed that MYB28 and MYB29 transcription factors play a role in ammonium tolerance, since its double mutant (myb28myb29) is highly hypersensitive toward ammonium nutrition in relation to altered Fe homeostasis. In the present work, we observed that primary root elongation was lower in the mutant with respect to wild-type plants under ammonium nutrition. Moreover, ammonium-induced lateral root branching was impaired in myb28myb29 in a Fe-supply dependent manner. Further research is required to decipher the link between MYB28 and MYB29 functions and the signaling pathway leading to root-system architecture modification by NH4 (+) supply.
PMID: 33538226
Plant Signal Behav , IF:1.671 , 2021 Feb , V16 (2) : P1848086 doi: 10.1080/15592324.2020.1848086
Superoxide anion generation response to wound in Arabidopsis hypocotyl cutting.
College of Life Sciences, Shaanxi Normal University , Xi'an, China.
Cutting is a frequently used model to study the process of adventitious root formation, and excision of cuttings leads to rapid wound response signaling. We recently showed that as a wound signal, reactive oxygen species (ROS, mainly hydrogen peroxide) participate in adventitious root induction of hypocotyl cuttings through regulation of auxin biosynthesis and transport. Here, superoxide anion (O2 (-*)), an early type of ROS, exhibited rapid burst at the cutting site immediately in response to wounding in Arabidopsis hypocotyl cuttings. Diphenylene iodonium chloride (DPI, inhibitor of NADPH oxidase) overwhelmingly suppressed O2 (-*) propagation through the hypocotyl. Compared to wild type, O2 (-*) burst only occur in cut base, and upward transduction were inhibited completely in NADPH oxidase mutant AtRbohD. These results indicate O2 (-*) generation and propagation in response to wound and via NADPH oxidase in adventitious root induction of hypocotyl cuttings.
PMID: 33210579
Mol Biol Rep , IF:1.402 , 2021 Feb doi: 10.1007/s11033-021-06197-0
Genome-wide identification and expression analysis of the TaYUCCA gene family in wheat.
State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Tai'an, 271018, Shandong, China.; State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Tai'an, 271018, Shandong, China. dsfeng@sdau.edu.cn.
Auxin is an important endogenous hormone in plants. The YUCCA gene encodes a flavin monooxygenase, which is an important rate-limiting enzyme in the auxin synthesis pathway and involved in the regulation of plant growth and development. In the study, we identified 63 wheat TaYUCCA genes; among them, some genes appeared in clusters. By constructing phylogenetic trees, we found that the TaYUCCA genes could be divided into six groups. In the WheatExp database, there were 22 differential expressed TaYUCCA genes, among which the TaYUCCA10 gene was abundantly expressed in the endosperm and medium milk stage, the TaYUCCA2 gene was abundantly expressed in the roots of three leaves and meiosis and transfer cells at 20 days post anthesis and the others 16 TaYUCCA genes had different expression level at different developmental stages in wheat, and there were 15 TaYUCCA genes induced by drought and heat stress, among which the TaYUCCA2-D, TaYUCCA3-B, and TaYUCCA9-D might be upregulated induced by drought stress, TaYUCCA10.1 might be upregulated induced drought and heat stress, TaYUCCA6-A was upregulated induced both drought and heat stress and the others 9 TaYUCCA genes were downregulated induced by drought and heat stress. Transcriptome and qRT-PCR analysis showed that TaYUCCA7-A was upregulated significantly after induced by powdery mildew. The comprehensive annotation and expression profiling of the TaYUCCA genes in this study enhanced our understanding of TaYUCCA family gene expression in wheat growth and development and laid the foundation for the further study of TaYUCCA gene mechanism.
PMID: 33547532
Curr Protoc , 2021 Feb , V1 (2) : Pe16 doi: 10.1002/cpz1.16
Methods for Rapid Protein Depletion in C. elegans using Auxin-Inducible Degradation.
Department of Molecular Biosciences, Northwestern University, Evanston, Illinois.
Numerous methods have been developed in model systems to deplete or inactivate proteins to elucidate their functional roles. In Caenorhabditis elegans, a common method for protein depletion is RNA interference (RNAi), in which mRNA is targeted for degradation. C. elegans is also a powerful genetic organism, amenable to large-scale genetic screens and CRISPR-mediated genome editing. However, these approaches largely lead to constitutive inhibition, which can make it difficult to study proteins essential for development or to dissect dynamic cellular processes. Thus, there have been recent efforts to develop methods to rapidly inactivate or deplete proteins to overcome these barriers. One such method that is proving to be exceptionally powerful is auxin-inducible degradation. In order to apply this approach in C. elegans, a 44-amino acid degron tag is added to the protein of interest, and the Arabidopsis ubiquitin ligase TIR1 is expressed in target tissues. When the plant hormone auxin is added, it mediates an interaction between TIR1 and the degron-tagged protein of interest, which triggers ubiquitination of the protein and its rapid degradation via the proteasome. Here, we have outlined multiple methods for inducing auxin-mediated depletion of target proteins in C. elegans, highlighting the versatility and power of this method. (c) 2021 Wiley Periodicals LLC. Basic Protocol 1: Long-term auxin-mediated depletion on plates Support Protocol: Preparation of NGM and NGM-auxin plates Basic Protocol 2: Rapid auxin-mediated depletion via soaking Basic Protocol 3: Acute auxin-mediated depletion in isolated embryos Basic Protocol 4: Assessing auxin-mediated depletion.
PMID: 33523606