Nature , IF:49.962 , 2021 Nov , V599 (7884) : P278-282 doi: 10.1038/s41586-021-03976-4
TMK-based cell-surface auxin signalling activates cell-wall acidification.
FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China.; Institute of Integrative Genome Biology and Department of Botany and Plant Science, University of California, Riverside, CA, USA.; Graduate School of Science, Nagoya University, Nagoya, Japan.; Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, Japan.; Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, USA.; Biological Mass Spectrometry Facility, Robert Wood Johnson Medical School and Rutgers, the State University of New Jersey, Piscataway, NJ, USA.; FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China. yang@ucr.edu.; Institute of Integrative Genome Biology and Department of Botany and Plant Science, University of California, Riverside, CA, USA. yang@ucr.edu.
The phytohormone auxin controls many processes in plants, at least in part through its regulation of cell expansion(1). The acid growth hypothesis has been proposed to explain auxin-stimulated cell expansion for five decades, but the mechanism that underlies auxin-induced cell-wall acidification is poorly characterized. Auxin induces the phosphorylation and activation of the plasma membrane H(+)-ATPase that pumps protons into the apoplast(2), yet how auxin activates its phosphorylation remains unclear. Here we show that the transmembrane kinase (TMK) auxin-signalling proteins interact with plasma membrane H(+)-ATPases, inducing their phosphorylation, and thereby promoting cell-wall acidification and hypocotyl cell elongation in Arabidopsis. Auxin induced interactions between TMKs and H(+)-ATPases in the plasma membrane within seconds, as well as TMK-dependent phosphorylation of the penultimate threonine residue on the H+-ATPases. Our genetic, biochemical and molecular evidence demonstrates that TMKs directly phosphorylate plasma membrane H(+)-ATPase and are required for auxin-induced H(+)-ATPase activation, apoplastic acidification and cell expansion. Thus, our findings reveal a crucial connection between auxin and plasma membrane H(+)-ATPase activation in regulating apoplastic pH changes and cell expansion through TMK-based cell surface auxin signalling.
PMID: 34707287
Nature , IF:49.962 , 2021 Nov , V599 (7884) : P273-277 doi: 10.1038/s41586-021-04037-6
Cell surface and intracellular auxin signalling for H(+) fluxes in root growth.
Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria.; Laboratory of Biochemistry, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, the Netherlands.; Institute of Transformative Bio-Molecules, Division of Biological Science, Nagoya University Chikusa, Nagoya, Japan.; Graduate School of Science, Nagoya University Chikusa, Nagoya, Japan.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.; VIB Center for Plant Systems Biology, Ghent, Belgium.; Tasmanian Institute of Agriculture, College of Science and Engineering, University of Tasmania, Hobart, Tasmania, Australia.; Department of Plant & Microbial Biology, University of Minnesota, St. Paul, MN, USA.; Laboratory of Plant Growth Analysis, Ghent University Global Campus, Incheon, Republic of Korea.; Department of Plants and Crops, HortiCell, Ghent University, Ghent, Belgium.; International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China.; Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria. jiri.friml@ist.ac.at.
Growth regulation tailors development in plants to their environment. A prominent example of this is the response to gravity, in which shoots bend up and roots bend down(1). This paradox is based on opposite effects of the phytohormone auxin, which promotes cell expansion in shoots while inhibiting it in roots via a yet unknown cellular mechanism(2). Here, by combining microfluidics, live imaging, genetic engineering and phosphoproteomics in Arabidopsis thaliana, we advance understanding of how auxin inhibits root growth. We show that auxin activates two distinct, antagonistically acting signalling pathways that converge on rapid regulation of apoplastic pH, a causative determinant of growth. Cell surface-based TRANSMEMBRANE KINASE1 (TMK1) interacts with and mediates phosphorylation and activation of plasma membrane H(+)-ATPases for apoplast acidification, while intracellular canonical auxin signalling promotes net cellular H(+) influx, causing apoplast alkalinization. Simultaneous activation of these two counteracting mechanisms poises roots for rapid, fine-tuned growth modulation in navigating complex soil environments.
PMID: 34707283
Trends Plant Sci , IF:18.313 , 2021 Nov doi: 10.1016/j.tplants.2021.10.012
Mechanisms of lysigenous aerenchyma formation under abiotic stress.
Bioscience and Biotechnology Center, Nagoya University, Nagoya, Japan; Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology (PRESTO), Kawaguchi, Japan. Electronic address: atkyama@agr.nagoya-u.ac.jp.; Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan; School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, Australia. Electronic address: nakazono@agr.nagoya-u.ac.jp.
Lysigenous aerenchyma is a gas space created by cortical cell death that enables efficient oxygen diffusion within plants and reduces the energy costs associated with root cells. Recent studies have demonstrated the benefits of aerenchyma formation under flooding, drought, and nutrient deficiency, although further studies will be necessary to understand the mechanisms involved.
PMID: 34810105
Nat Plants , IF:15.793 , 2021 Nov , V7 (11) : P1453-1460 doi: 10.1038/s41477-021-01015-8
Pluripotency acquisition in the middle cell layer of callus is required for organ regeneration.
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.; University of Chinese Academy of Sciences, Beijing, China.; National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China. xulin@cemps.ac.cn.
In plant tissue culture, callus forms from detached explants in response to a high-auxin-to-low-cytokinin ratio on callus-inducing medium. Callus is a group of pluripotent cells because it can regenerate either roots or shoots in response to a low level of auxin on root-inducing medium or a high-cytokinin-to-low-auxin ratio on shoot-inducing medium, respectively(1). However, our knowledge of the mechanism of pluripotency acquisition during callus formation is limited. On the basis of analyses at the single-cell level, we show that the tissue structure of Arabidopsis thaliana callus on callus-inducing medium is similar to that of the root primordium or root apical meristem, and the middle cell layer with quiescent centre-like transcriptional identity exhibits the ability to regenerate organs. In the middle cell layer, WUSCHEL-RELATED HOMEOBOX5 (WOX5) directly interacts with PLETHORA1 and 2 to promote TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 expression for endogenous auxin production. WOX5 also interacts with the B-type ARABIDOPSIS RESPONSE REGULATOR12 (ARR12) and represses A-type ARRs to break the negative feedback loop in cytokinin signalling. Overall, the promotion of auxin production and the enhancement of cytokinin sensitivity are both required for pluripotency acquisition in the middle cell layer of callus for organ regeneration.
PMID: 34782770
Nat Commun , IF:14.919 , 2021 Nov , V12 (1) : P6752 doi: 10.1038/s41467-021-27020-1
The main oxidative inactivation pathway of the plant hormone auxin.
Department of Biochemistry, Okayama University of Science, Okayama, 700-0005, Japan. hayashi@dbc.ous.ac.jp.; Department of Biochemistry, Okayama University of Science, Okayama, 700-0005, Japan.; Department of Biological Production Science, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan.; Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan.; Section of Cell and Developmental Biology, University of California San Diego, Gilman Dr. La Jolla, San Diego, CA, 92093-0116, USA.; RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045, Japan.
Inactivation of the phytohormone auxin plays important roles in plant development, and several enzymes have been implicated in auxin inactivation. In this study, we show that the predominant natural auxin, indole-3-acetic acid (IAA), is mainly inactivated via the GH3-ILR1-DAO pathway. IAA is first converted to IAA-amino acid conjugates by GH3 IAA-amidosynthetases. The IAA-amino acid conjugates IAA-aspartate (IAA-Asp) and IAA-glutamate (IAA-Glu) are storage forms of IAA and can be converted back to IAA by ILR1/ILL amidohydrolases. We further show that DAO1 dioxygenase irreversibly oxidizes IAA-Asp and IAA-Glu into 2-oxindole-3-acetic acid-aspartate (oxIAA-Asp) and oxIAA-Glu, which are subsequently hydrolyzed by ILR1 to release inactive oxIAA. This work established a complete pathway for the oxidative inactivation of auxin and defines the roles played by auxin homeostasis in plant development.
PMID: 34811366
Mol Plant , IF:13.164 , 2021 Nov , V14 (11) : P1799-1813 doi: 10.1016/j.molp.2021.07.001
The INO80 chromatin remodeling complex promotes thermomorphogenesis by connecting H2A.Z eviction and active transcription in Arabidopsis.
State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing, China.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China. Electronic address: dhjiang@genetics.ac.cn.
Global warming poses a major threat to plant growth and crop production. In some plants, including Arabidopsis thaliana, elevated temperatures induce a series of morphological and developmental adjustments termed thermomorphogenesis, which facilitates plant cooling under high-temperature conditions. Plant thermal response is suppressed by histone variant H2A.Z. At warm temperatures, H2A.Z is evicted from nucleosomes at thermoresponsive genes, resulting in changes in their expression. However, the mechanisms that regulate H2A.Z eviction and subsequent transcriptional changes are largely unknown. Here, we show that the INO80 chromatin remodeling complex (INO80-C) promotes thermomorphogenesis and activates the expression of thermoresponsive and auxin-related genes. INO80-C associates with PHYTOCHROME-INTERACTING FACTOR 4 (PIF4), a potent regulator of thermomorphogenesis, and mediates temperature-induced H2A.Z eviction at PIF4 targets. Moreover, INO80-C directly interacts with COMPASS-like and transcription elongation factors to promote active histone modification, histone H3 lysine 4 trimethylation, and RNA polymerase II elongation, leading to the thermal induction of transcription. Notably, the transcription elongation factors SPT4 and SPT5 are required for H2A.Z eviction at PIF4 targets, suggesting the cooperation of INO80-C and transcription elongation in H2A.Z removal. Taken together, these results suggest that the (PIF4)-(INO80-C)-(COMPASS-like)-(transcription elongator) module controls plant thermal response, thereby establishing a link between H2A.Z eviction and active transcription.
PMID: 34242850
Plant Cell , IF:11.277 , 2021 Nov , V33 (11) : P3513-3531 doi: 10.1093/plcell/koab207
Calcium-dependent protein kinase 29 modulates PIN-FORMED polarity and Arabidopsis development via its own phosphorylation code.
Department of Biological Sciences, Seoul National University, Seoul 08826, Korea.
PIN-FORMED (PIN)-mediated polar auxin transport (PAT) is involved in key developmental processes in plants. Various internal and external cues influence plant development via the modulation of intracellular PIN polarity and, thus, the direction of PAT, but the mechanisms underlying these processes remain largely unknown. PIN proteins harbor a hydrophilic loop (HL) that has important regulatory functions; here, we used the HL as bait in protein pulldown screening for modulators of intracellular PIN trafficking in Arabidopsis thaliana. Calcium-dependent protein kinase 29 (CPK29), a Ca2+-dependent protein kinase, was identified and shown to phosphorylate specific target residues on the PIN-HL that were not phosphorylated by other kinases. Furthermore, loss of CPK29 or mutations of the phospho-target residues in PIN-HLs significantly compromised intracellular PIN trafficking and polarity, causing defects in PIN-mediated auxin redistribution and biological processes such as lateral root formation, root twisting, hypocotyl gravitropism, phyllotaxis, and reproductive development. These findings indicate that CPK29 directly interprets Ca2+ signals from internal and external triggers, resulting in the modulation of PIN trafficking and auxin responses.
PMID: 34402905
Curr Biol , IF:10.834 , 2021 Nov doi: 10.1016/j.cub.2021.10.044
KAI2 promotes Arabidopsis root hair elongation at low external phosphate by controlling local accumulation of AUX1 and PIN2.
Plant Genetics, TUM School of Life Sciences, Technical University of Munich (TUM), Emil Ramann Str. 4, 85354 Freising, Germany.; School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.; Plant Genetics, TUM School of Life Sciences, Technical University of Munich (TUM), Emil Ramann Str. 4, 85354 Freising, Germany. Electronic address: caroline.gutjahr@tum.de.
Root hair (RH) growth to increase the absorptive root surface area is a key adaptation of plants to limiting phosphate availability in soils. Despite the importance of this trait, especially for seedling survival, little is known about the molecular events connecting phosphate starvation sensing and RH growth regulation. KARRIKIN INSENSITIVE2 (KAI2), an alpha/beta-hydrolase receptor of a yet-unknown plant hormone ("KAI2-ligand" [KL]), is required for RH elongation.(1) KAI2 interacts with the F-box protein MORE AXILLIARY BRANCHING2 (MAX2) to target regulatory proteins of the SUPPRESSOR of MAX2 1 (SMAX1) family for degradation.(2) Here, we demonstrate that Pi starvation increases KL signaling in Arabidopsis roots through transcriptional activation of KAI2 and MAX2. Both genes are required for RH elongation under these conditions, while smax1 smxl2 mutants have constitutively long RHs, even at high Pi availability. Attenuated RH elongation in kai2 mutants is explained by reduced shootward auxin transport from the root tip resulting in reduced auxin signaling in the RH zone, caused by an inability to increase localized accumulation of the auxin importer AUXIN TRANSPORTER PROTEIN1 (AUX1) and the auxin exporter PIN-FORMED2 (PIN2) upon Pi starvation. Consistent with AUX1 and PIN2 accumulation being mediated via ethylene signaling,(3) expression of 1-AMINOCYCLOPROPANE-1-CARBOXYLATE SYNTHASE 7 (ACS7) is increased at low Pi in a KAI2-dependent manner, and treatment with an ethylene precursor restores RH elongation of acs7, but not of aux1 and pin2. Thus, KAI2 signaling is increased by phosphate starvation to trigger an ethylene- AUX1/PIN2-auxin cascade required for RH elongation.
PMID: 34758285
Curr Biol , IF:10.834 , 2021 Nov , V31 (22) : P4946-4955.e4 doi: 10.1016/j.cub.2021.09.019
Auxin-dependent control of cytoskeleton and cell shape regulates division orientation in the Arabidopsis embryo.
Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 Wageningen, the Netherlands. Electronic address: prasad.vaddepalli@zmbp.uni-tuebingen.de.; Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 Wageningen, the Netherlands.; Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, Cologne, Germany.; Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, Weinberg 3, Halle (Saale), Germany.; Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, Cologne, Germany; John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.; Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 Wageningen, the Netherlands. Electronic address: dolf.weijers@wur.nl.
Premitotic control of cell division orientation is critical for plant development, as cell walls prevent extensive cell remodeling or migration. While many divisions are proliferative and add cells to existing tissues, some divisions are formative and generate new tissue layers or growth axes. Such formative divisions are often asymmetric in nature, producing daughters with different fates. We have previously shown that, in the Arabidopsis thaliana embryo, developmental asymmetry is correlated with geometric asymmetry, creating daughter cells of unequal volume. Such divisions are generated by division planes that deviate from a default "minimal surface area" rule. Inhibition of auxin response leads to reversal to this default, yet the mechanisms underlying division plane choice in the embryo have been unclear. Here, we show that auxin-dependent division plane control involves alterations in cell geometry, but not in cell polarity axis or nuclear position. Through transcriptome profiling, we find that auxin regulates genes controlling cell wall and cytoskeleton properties. We confirm the involvement of microtubule (MT)-binding proteins in embryo division control. Organization of both MT and actin cytoskeleton depends on auxin response, and genetically controlled MT or actin depolymerization in embryos leads to disruption of asymmetric divisions, including reversion to the default. Our work shows how auxin-dependent control of MT and actin cytoskeleton properties interacts with cell geometry to generate asymmetric divisions during the earliest steps in plant development.
PMID: 34610273
New Phytol , IF:10.151 , 2021 Nov doi: 10.1111/nph.17878
Phytochrome Interacting Factor 3 regulates pollen mitotic division through auxin signaling and sugar metabolism pathways in tomato.
Department of Horticulture, Zhejiang University, Hangzhou, 310058, China.; Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg, 69120, Germany.; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agricultural, Zhejiang University, Hangzhou, 310058, China.
The development of viable pollen determines male fertility, and is crucial for reproduction in flowering plants. Phytochrome-Interacting Factor 3 (PIF3) acts as a central regulator of plant growth and development, but its relationship with pollen development has not been determined. Through genetic, histological and transcriptomic analyses, we identified an essential role for SlPIF3 in regulating tomato (Solanum lycopersicum) pollen development. Knocking out SlPIF3 using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 resulted in pollen mitosis I (PMI) arrest, and a failure to form viable pollen. We further demonstrated that both glutamate synthase 1 (SlGLT1) and cell wall invertase 9 (SlCWIN9), involved in auxin and sugar homeostasis, respectively, colocalized with SlPIF3 in the anthers and were directly regulated by SlPIF3. Knockout of either SlGLT1 or SlCWIN9 phenocopied the pollen phenotype of SlPIF3 knockout (Slpif3) lines. Slpif3 fertility was partially restored by exogenous auxin (IAA) in a dose-dependent manner. This study reveals a mechanism by which SlPIF3 regulates pollen development and highlights a new strategy for creating hormone-regulated genic male-sterile lines for tomato hybrid seed production.
PMID: 34812499
New Phytol , IF:10.151 , 2021 Nov , V232 (4) : P1661-1673 doi: 10.1111/nph.17687
Osmotic stress represses root growth by modulating the transcriptional regulation of PIN-FORMED3.
State Key Laboratory of Hybrid Rice, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, 430072, China.
Osmotic stress influences root system architecture, and polar auxin transport (PAT) is well established to regulate root growth and development. However, how PAT responds to osmotic stress at the molecular level remains poorly understood. In this study, we explored whether and how the auxin efflux carrier PIN-FORMED3 (PIN3) participates in osmotic stress-induced root growth inhibition in Arabidopsis (Arabidopsis thaliana). We observed that osmotic stress induces a HD-ZIP II transcription factor-encoding gene HOMEODOMAIN ARABIDOPSIS THALIANA2 (HAT2) expression in roots. The hat2 loss-of-function mutant is less sensitive to osmotic stress in terms of root meristem growth. Consistent with this phenotype, whereas the auxin response is downregulated in wild-type roots under osmotic stress, the inhibition of auxin response by osmotic stress was alleviated in hat2 roots. Conversely, transgenic lines overexpressing HAT2 (Pro35S::HAT2) had shorter roots and reduced auxin accumulation compared with wild-type plants. PIN3 expression was significantly reduced in the Pro35S::HAT2 lines. We determined that osmotic stress-mediated repression of PIN3 was alleviated in the hat2 mutant because HAT2 normally binds to the promoter of PIN3 and inhibits its expression. Taken together, our data revealed that osmotic stress inhibits root growth via HAT2, which regulates auxin activity by directly repressing PIN3 transcription.
PMID: 34420215
Cold Spring Harb Perspect Biol , IF:10.005 , 2021 Nov , V13 (11) doi: 10.1101/cshperspect.a040014
Uncovering How Auxin Optimizes Root Systems Architecture in Response to Environmental Stresses.
Plant and Crop Sciences, School of Biosciences, Sutton Bonington Campus, The University of Nottingham, Loughborough LE12 5RD, United Kingdom.
Since colonizing land, plants have developed mechanisms to tolerate a broad range of abiotic stresses that include flooding, drought, high salinity, and nutrient limitation. Roots play a key role acclimating plants to these as their developmental plasticity enables them to grow toward more favorable conditions and away from limiting or harmful stresses. The phytohormone auxin plays a key role translating these environmental signals into developmental outputs. This is achieved by modulating auxin levels and/or signaling, often through cross talk with other hormone signals like abscisic acid (ABA) or ethylene. In our review, we discuss how auxin controls root responses to water, osmotic and nutrient-related stresses, and describe how the synthesis, degradation, transport, and response of this key signaling hormone helps optimize root architecture to maximize resource acquisition while limiting the impact of abiotic stresses.
PMID: 33903159
Cold Spring Harb Perspect Biol , IF:10.005 , 2021 Nov , V13 (11) doi: 10.1101/cshperspect.a040006
Casting the Net-Connecting Auxin Signaling to the Plant Genome.
Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, D-69120 Heidelberg, Germany.; Cell Wall Signalling Group, Centre for Organismal Studies, Heidelberg University, D-69120 Heidelberg, Germany.
Auxin represents one of the most potent and most versatile hormonal signals in the plant kingdom. Built on a simple core of only a few dedicated components, the auxin signaling system plays important roles for diverse aspects of plant development, physiology, and defense. Key to the diversity of context-dependent functional outputs generated by cells in response to this small molecule are gene duplication events and sub-functionalization of signaling components on the one hand, and a deep embedding of the auxin signaling system into complex regulatory networks on the other hand. Together, these evolutionary innovations provide the mechanisms to allow each cell to display a highly specific auxin response that suits its individual requirements. In this review, we discuss the regulatory networks connecting auxin with a large number of diverse pathways at all relevant levels of the signaling system ranging from biosynthesis to transcriptional response.
PMID: 33903151
Cell Rep , IF:9.423 , 2021 Nov , V37 (6) : P109980 doi: 10.1016/j.celrep.2021.109980
Arabidopsis ATXR2 represses de novo shoot organogenesis in the transition from callus to shoot formation.
Department of Chemistry, Seoul National University, Seoul 08826, Korea; Research Institute of Basic Sciences, Seoul National University, Seoul 08826, Korea.; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea.; Division of Horticultural Biotechnology, Hankyong National University, Anseong 17579, Korea.; Department of Chemistry and Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul 04763, Korea.; Department of Bioenergy Science and Technology and Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Korea.; Department of Chemistry, Seoul National University, Seoul 08826, Korea; Research Institute of Basic Sciences, Seoul National University, Seoul 08826, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea. Electronic address: pjseo1@snu.ac.kr.
Plants exhibit high regenerative capacity, which is controlled by various genetic factors. Here, we report that ARABIDOPSIS TRITHORAX-RELATED 2 (ATXR2) controls de novo shoot organogenesis by regulating auxin-cytokinin interaction. The auxin-inducible ATXR2 Trithorax Group (TrxG) protein temporally interacts with the cytokinin-responsive type-B ARABIDOPSIS RESPONSE REGULATOR 1 (ARR1) at early stages of shoot regeneration. The ATXR2-ARR1 complex binds to and deposits the H3K36me3 mark in the promoters of a subset of type-A ARR genes, ARR5 and ARR7, thus activating their expression. Consequently, the ATXR2/ARR1-type-A ARR module transiently represses cytokinin signaling and thereby de novo shoot regeneration. The atxr2-1 mutant calli exhibit enhanced shoot regeneration with low expression of ARR5 and ARR7, which ultimately upregulates WUSCHEL (WUS) expression. Thus, ATXR2 regulates cytokinin signaling and prevents premature WUS activation to ensure proper cell fate transition, and the auxin-cytokinin interaction underlies the initial specification of shoot meristem in callus.
PMID: 34758306
Plant Physiol , IF:8.34 , 2021 Nov doi: 10.1093/plphys/kiab536
Piriformospora indica recruits host-derived putrescine for growth promotion in plants.
National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, New Delhi 110067, India.
Growth promotion induced by the endosymbiont Piriformospora indica has been observed in various plants; however, except growth phytohormones, specific functional metabolites involved in P. indica-mediated growth promotion are unknown. Here, we used a GC-MS based untargeted metabolite analysis to identify tomato (Solanum lycopersicum) metabolites whose levels were altered during P. indica-mediated growth promotion. Metabolomic multivariate analysis revealed several primary metabolites with altered levels, with putrescine induced most significantly in roots during the interaction. Further, our results indicated that P. indica modulates the arginine decarboxylase (ADC)-mediated putrescine biosynthesis pathway via induction of SlADC1 in tomato. P. indica did not promote growth in Sladc1-VIGS (virus-induced gene silencing of SlADC1) lines of tomato tomato and showed less colonization. Furthermore, using LC-MS/MS we showed that putrescine promoted growth by elevation of auxin (indole-3-acetic acid) and gibberellin (GA4, GA7) levels in tomato. In Arabidopsis (Arabidopsis thaliana) adc knock-out mutants, P. indica colonization also decreased and showed no plant growth promotion, and this response was rescued upon exogenous application of putrescine. Putrescine is also important for hyphal growth of P. indica, indicating that it is co-adapted by both host and microbe. Taken together, we conclude that putrescine is an essential metabolite and its biosynthesis in plants is crucial for P. indica-mediated plant growth promotion and fungal growth.
PMID: 34791442
Plant Physiol , IF:8.34 , 2021 Nov doi: 10.1093/plphys/kiab520
TINY ROOT HAIR 1: uncoupling transporter function in auxin-mediated gravitropism and root hair growth.
University of Melbourne.
PMID: 34747493
Plant Physiol , IF:8.34 , 2021 Nov , V187 (3) : P1189-1201 doi: 10.1093/plphys/kiab237
The role of auxin and sugar signaling in dominance inhibition of inflorescence growth by fruit load.
CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA 5064, Australia.
Dominance inhibition of shoot growth by fruit load is a major factor that regulates shoot architecture and limits yield in agriculture and horticulture crops. In annual plants, the inhibition of inflorescence growth by fruit load occurs at a late stage of inflorescence development termed the end of flowering transition. Physiological studies show this transition is mediated by production and export of auxin from developing fruits in close proximity to the inflorescence apex. In the meristem, cessation of inflorescence growth is controlled in part by the age-dependent pathway, which regulates the timing of arrest. Here, we show the end of flowering transition is a two-step process in Arabidopsis (Arabidopsis thaliana). The first stage is characterized by a cessation of inflorescence growth, while immature fruit continues to develop. At this stage, dominance inhibition of inflorescence growth by fruit load is associated with a selective dampening of auxin transport in the apical region of the stem. Subsequently, an increase in auxin response in the vascular tissues of the apical stem where developing fruits are attached marks the second stage for the end of flowering transition. Similar to the vegetative and floral transition, the end of flowering transition is associated with a change in sugar signaling and metabolism in the inflorescence apex. Taken together, our results suggest that during the end of flowering transition, dominance inhibition of inflorescence shoot growth by fruit load is mediated by auxin and sugar signaling.
PMID: 34734274
Plant Physiol , IF:8.34 , 2021 Nov , V187 (3) : P1235-1249 doi: 10.1093/plphys/kiab410
Phototropin-mediated perception of light direction in leaves regulates blade flattening.
Centre for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland.
One conserved feature among angiosperms is the development of flat thin leaves. This developmental pattern optimizes light capture and gas exchange. The blue light (BL) receptors phototropins are required for leaf flattening, with the null phot1phot2 mutant showing curled leaves in Arabidopsis (Arabidopsis thaliana). However, key aspects of their function in leaf development remain unknown. Here, we performed a detailed spatiotemporal characterization of phototropin function in Arabidopsis leaves. We found that phototropins perceive light direction in the blade, and, similar to their role in hypocotyls, they control the spatial pattern of auxin signaling, possibly modulating auxin transport, to ultimately regulate cell expansion. Phototropin signaling components in the leaf partially differ from hypocotyls. Moreover, the light response on the upper and lower sides of the leaf blade suggests a partially distinct requirement of phototropin signaling components on each side. In particular, NON PHOTOTROPIC HYPOCOTYL 3 showed an adaxial-specific function. In addition, we show a prominent role of PHYTOCHROME KINASE SUBSTRATE 3 in leaf flattening. Among auxin transporters, PIN-FORMED 3,4,7 and AUXIN RESISTANT 1 (AUX1)/LIKE AUXIN RESISTANT 1 (LAX1) are required for the response while ABCB19 has a regulatory role. Overall, our results show that directional BL perception by phototropins is a key aspect of leaf development, integrating endogenous and exogenous signals.
PMID: 34618121
Plant Physiol , IF:8.34 , 2021 Nov , V187 (3) : P1399-1413 doi: 10.1093/plphys/kiab369
A small molecule antagonizes jasmonic acid perception and auxin responses in vascular and nonvascular plants.
Departamento de Genetica Molecular de Plantas, Centro Nacional de Biotecnologia-CSIC, Campus Universidad Autonoma, Madrid, 28049, Spain.; Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, California, 92521, USA.
The phytohormone jasmonoyl-L-isoleucine (JA-Ile) regulates many stress responses and developmental processes in plants. A co-receptor complex formed by the F-box protein Coronatine Insensitive 1 (COI1) and a Jasmonate (JA) ZIM-domain (JAZ) repressor perceives the hormone. JA-Ile antagonists are invaluable tools for exploring the role of JA-Ile in specific tissues and developmental stages, and for identifying regulatory processes of the signaling pathway. Using two complementary chemical screens, we identified three compounds that exhibit a robust inhibitory effect on both the hormone-mediated COI-JAZ interaction and degradation of JAZ1 and JAZ9 in vivo. One molecule, J4, also restrains specific JA-induced physiological responses in different angiosperm plants, including JA-mediated gene expression, growth inhibition, chlorophyll degradation, and anthocyanin accumulation. Interaction experiments with purified proteins indicate that J4 directly interferes with the formation of the Arabidopsis (Arabidopsis thaliana) COI1-JAZ complex otherwise induced by JA. The antagonistic effect of J4 on COI1-JAZ also occurs in the liverwort Marchantia polymorpha, suggesting the mode of action is conserved in land plants. Besides JA signaling, J4 works as an antagonist of the closely related auxin signaling pathway, preventing Transport Inhibitor Response1/Aux-indole-3-acetic acid interaction and auxin responses in planta, including hormone-mediated degradation of an auxin repressor, gene expression, and gravitropic response. However, J4 does not affect other hormonal pathways. Altogether, our results show that this dual antagonist competes with JA-Ile and auxin, preventing the formation of phylogenetically related receptor complexes. J4 may be a useful tool to dissect both the JA-Ile and auxin pathways in particular tissues and developmental stages since it reversibly inhibits these pathways. One-sentence summary: A chemical screen identified a molecule that antagonizes jasmonate perception by directly interfering with receptor complex formation in phylogenetically distant vascular and nonvascular plants.
PMID: 34618088
Plant Physiol , IF:8.34 , 2021 Nov , V187 (3) : P1690-1703 doi: 10.1093/plphys/kiab332
CYCLIC NUCLEOTIDE-GATED ION CHANNEL 2 modulates auxin homeostasis and signaling.
Department of Cell and Systems Biology, University of Toronto, Toronto, , Canada, ON M5S 3B2.; Department of Biochemistry and Molecular Biology, Saitama University, Sakura-ku, Saitama, 338-8570, Japan.; PhenoLogic Co., Toronto, Canada, ON M5A 2N1.; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.; Faculty of Bioscience Engineering, Department Plants and Crops, Ghent University, Unit HortiCell, Coupure Links 653, 9000 Ghent, Belgium.; Lab of Plant Growth Analysis, Ghent University Global Campus, Songdomunhwa-Ro, 119, Yeonsu-gu, Incheon 21985, Republic of Korea.; Department of Botany, University of Wisconsin, Madison, WI 53706, USA.; Center for the Analysis of Genome Evolution and Function (CAGEF), University of Toronto, Toronto, Canada, ON M5S 3B2.
Cyclic nucleotide-gated ion channels (CNGCs) have been firmly established as Ca2+-conducting ion channels that regulate a wide variety of physiological responses in plants. CNGC2 has been implicated in plant immunity and Ca2+ signaling due to the autoimmune phenotypes exhibited by null mutants of CNGC2 in Arabidopsis thaliana. However, cngc2 mutants display additional phenotypes that are unique among autoimmune mutants, suggesting that CNGC2 has functions beyond defense and generates distinct Ca2+ signals in response to different triggers. In this study, we found that cngc2 mutants showed reduced gravitropism, consistent with a defect in auxin signaling. This was mirrored in the diminished auxin response detected by the auxin reporters DR5::GUS and DII-VENUS and in a strongly impaired auxin-induced Ca2+ response. Moreover, the cngc2 mutant exhibits higher levels of the endogenous auxin indole-3-acetic acid, indicating that excess auxin in the cngc2 mutant causes its pleiotropic phenotypes. These auxin signaling defects and the autoimmunity syndrome of the cngc2 mutant could be suppressed by loss-of-function mutations in the auxin biosynthesis gene YUCCA6 (YUC6), as determined by identification of the cngc2 suppressor mutant repressor of cngc2 (rdd1) as an allele of YUC6. A loss-of-function mutation in the upstream auxin biosynthesis gene TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA1, WEAK ETHYLENE INSENSITIVE8) also suppressed the cngc2 phenotypes, further supporting the tight relationship between CNGC2 and the TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS-YUCCA -dependent auxin biosynthesis pathway. Taking these results together, we propose that the Ca2+ signal generated by CNGC2 is a part of the negative feedback regulation of auxin homeostasis in which CNGC2 balances cellular auxin perception by influencing auxin biosynthesis.
PMID: 34618044
Plant Physiol , IF:8.34 , 2021 Nov , V187 (3) : P1577-1586 doi: 10.1093/plphys/kiab341
Auxin controls the division of root endodermal cells.
School of Biological Sciences and Technology, Chonnam National University, Gwangju 61186, Republic of Korea.; The National Academy of Sciences, Seoul 06579, Republic of Korea.
The root endodermis forms a selective barrier that prevents the free diffusion of solutes into the vasculature; to make this barrier, endodermal cells deposit hydrophobic compounds in their cell walls, forming the Casparian strip. Here, we showed that, in contrast to vascular and epidermal root cells, endodermal root cells do not divide alongside the root apical meristem in Arabidopsis thaliana. Auxin treatment induced division of endodermal cells in wild-type plants, but not in the auxin signaling mutant auxin resistant3-1. Endodermis-specific activation of auxin responses by expression of truncated AUXIN-RESPONSIVE FACTOR5 (DeltaARF5) in root endodermal cells under the control of the ENDODERMIS7 promoter (EN7::DeltaARF5) also induced endodermal cell division. We used an auxin transport inhibitor to cause accumulation of auxin in endodermal cells, which induced endodermal cell division. In addition, knockout of P-GLYCOPROTEIN1 (PGP1) and PGP19, which mediate centripetal auxin flow, promoted the division of endodermal cells. Together, these findings reveal a tight link between the endodermal auxin response and endodermal cell division, suggesting that auxin is a key regulator controlling the division of root endodermal cells, and that PGP1 and PGP19 are involved in regulating endodermal cell division.
PMID: 34618030
Elife , IF:8.14 , 2021 Nov , V10 doi: 10.7554/eLife.72132
A coupled mechano-biochemical model for cell polarity guided anisotropic root growth.
CBGP Centro de Biotecnologia y Genomica de Plantas UPM-INIA, Pozuelo de Alarcon, Spain.; Institute of Science and Technology (IST), Klosterneuburg, Austria.
Plants develop new organs to adjust their bodies to dynamic changes in the environment. How independent organs achieve anisotropic shapes and polarities is poorly understood. To address this question, we constructed a mechano-biochemical model for Arabidopsis root meristem growth that integrates biologically plausible principles. Computer model simulations demonstrate how differential growth of neighboring tissues results in the initial symmetry-breaking leading to anisotropic root growth. Furthermore, the root growth feeds back on a polar transport network of the growth regulator auxin. Model, predictions are in close agreement with in vivo patterns of anisotropic growth, auxin distribution, and cell polarity, as well as several root phenotypes caused by chemical, mechanical, or genetic perturbations. Our study demonstrates that the combination of tissue mechanics and polar auxin transport organizes anisotropic root growth and cell polarities during organ outgrowth. Therefore, a mobile auxin signal transported through immobile cells drives polarity and growth mechanics to coordinate complex organ development.
PMID: 34723798
Curr Opin Plant Biol , IF:7.834 , 2021 Nov , V65 : P102115 doi: 10.1016/j.pbi.2021.102115
Cellular and molecular bases of lateral root initiation and morphogenesis.
Departamento de Biologia Molecular de Plantas, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico (UNAM), Cuernavaca, 62210, Morelos, Mexico.; Departamento de Biologia Molecular de Plantas, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico (UNAM), Cuernavaca, 62210, Morelos, Mexico. Electronic address: joseph.dubrovsky@ibt.unam.mx.
Lateral root development is essential for the establishment of the plant root system. Lateral root initiation is a multistep process that impacts early primordium morphogenesis and is linked to the formation of a morphogenetic field of pericycle founder cells. Gradual recruitment of founder cells builds this morphogenetic field in an auxin-dependent manner. The complex process of lateral root primordium morphogenesis includes several subprocesses, which are presented in this review. The underlying cellular and molecular mechanisms of these subprocesses are examined.
PMID: 34742019
Plant Cell Environ , IF:7.228 , 2021 Nov doi: 10.1111/pce.14229
Insights into ROS-dependent signalling underlying transcriptomic plant responses to the herbicide 2,4-D.
Departamento de Bioquimica, Biologia Celular y Molecular de Plantas, EEZ, CSIC, C/Prof. Albareda, 18008, Granada, Spain.; Education Faculty, University of Granada, Melilla, Spain.; Bioinformatics Unit, IPBLN, CSIC, Granada, Spain.; Plataforma Andaluza de Bioinformatica-SCBI, Universidad de Malaga, C/Severo Ochoa 34, 29590, Malaga, Spain.; Department Ciencies Agraries i del Medi Natural, Universitat Jaume I, E-12071, Castello de la Plana, Spain.; Departamento de Biologia Molecular y Bioquimica, Ciencias, Univ. de Malaga, Campus de Teatinos s/n, 29071, Malaga, Spain.; Institute for Mediterranean and Subtropical Horticulture "La Mayora" (IHSM-UMA-CSIC), Av. Louis Pasteur, 49, 29010, Malaga, Spain.; Instituto de Biologia Molecular y Celular de Plantas (CSIC-Univ. Valencia), CPI Edificio 8E, Avda. Ingeniero Fausto Elio s/n, 46022, Valencia, Spain.
The synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) functions as an agronomic weed control herbicide. High concentrations of 2,4-D induce plant growth defects, particularly leaf epinasty and stem curvature. Although the 2,4-D-triggered ROS production, little is known about its signalling. In this study, by using a null mutant in peroxisomal acyl CoA oxidase 1 (acx1-2), we identified ACX1 as one of the main sources of ROS production and, in part, also causing the epinastic phenotype following 2,4-D application. Transcriptomic analyses of WT plants after treatment with 2,4-D revealed a ROS-related peroxisomal footprint in early plant responses, while other organelles, such as mitochondria and chloroplasts, are involved in later responses. Interestingly, a group of 2,4-D-responsive ACX1-dependent transcripts previously associated with epinasty is related to auxin biosynthesis, metabolism and signalling. We found that the auxin receptor AUXIN SIGNALING F-BOX 3 (AFB3), a component of SCF (ASK-cullin-F-box) E3 ubiquitin ligase complexes, which mediates AUX/IAA degradation by the 26S proteasome, acts downstream of ACX1 and is involved in the epinastic phenotype induced by 2,4-D. We also found that protein degradation associated with ubiquitin E3-RING and E3-SCF-FBOX in ACX1-dependent signalling in plant responses to 2,4-D is significantly regulated over longer treatment periods. This article is protected by copyright. All rights reserved.
PMID: 34800292
Plant Cell Environ , IF:7.228 , 2021 Nov doi: 10.1111/pce.14230
The volatile cedrene from Trichoderma guizhouense modulates Arabidops is root development through auxin transport and signaling.
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, 210095, 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, 210095, 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, 100081, China.
Rhizosphere microorganisms interact with plant roots by producing chemical signals that regulate root development. However, the distinct bioactive compounds and signal transduction pathways remain to be identified. Here, we showed that sesquiterpenes are the main volatile compounds produced by plant-beneficial Trichoderma guizhouense NJAU4742. Inhibition of sesquiterpene biosynthesis eliminated the promoting effect of this strain on root growth, indicating its involvement in plant-fungus cross-kingdom signaling. Sesquiterpene component analysis identified cedrene, a highly abundant sesquiterpene in strain NJAU4742, to stimulate plant growth and root development. Genetic analysis and auxin transport inhibition showed that the TIR1 and AFB2 auxin receptors, IAA14 auxin-responsive protein, and ARF7 and ARF19 transcription factors affected the response of lateral roots to cedrene. Moreover, the AUX1 auxin influx carrier and PIN2 efflux carrier were also found to be indispensable for cedrene-induced lateral root formation. Confocal imaging showed that cedrene affected the expression of pPIN2:PIN2:GFP and pPIN3:PIN3:GFP, which might be related to the effect of cedrene on root morphology. These results suggested that a novel sesquiterpene molecule from plant-beneficial T. guizhouense regulates plant root development through the transport and signaling of auxin. This article is protected by copyright. All rights reserved.
PMID: 34800291
Plant Cell Environ , IF:7.228 , 2021 Nov doi: 10.1111/pce.14216
(+)-Catechin, epicatechin and epigallocatechin gallate are important inducible defensive compounds against Ectropis grisescens in tea plants.
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, China.; Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture and Rural Affairs, Hangzhou, China.
The tea plant, Camellia sinensis (L.) O. Kuntze, is an economically important, perennial woody plant rich in catechins. Although catechins have been reported to play an important role in plant defences against microbes, their roles in the defence of tea plants against herbivores remain unknown. In this study, we allowed the larvae of Ectropis grisescens, a leaf-feeding pest, to feed on the plants, and alternatively, we wounded the plants and then treated them with E. grisescens oral secretions (WOS). Both approaches triggered jasmonic acid-, ethylene- and auxin-mediated signalling pathways; as a result, plants accumulated three catechin compounds: (+)-catechin, epicatechin and epigallocatechin. Not only was the mass of E. grisescens larvae fed on plants previously infested with E. grisescens or treated with WOS significantly lower than that of larvae fed on controls, but also artificial diet supplemented with epicatechin, (+)-catechin or epigallocatechin gallate reduced larval growth rates. In addition, the exogenous application of jasmonic acid, ethylene or auxin induced the biosynthesis of the three catechins, which, in turn, enhanced the resistance of tea plants to E. grisescens, leading to the coordination of the three signalling pathways. Our results suggest that the three catechins play an important role in the defences of tea plants against E. grisescens.
PMID: 34719788
J Integr Plant Biol , IF:7.061 , 2021 Nov doi: 10.1111/jipb.13190
Growth asymmetry precedes differential auxin response during apical hook initiation in Arabidopsis.
Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, 518055, China.; Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, 518055, China.; Department of Biology, Faculty of Science, Hong Kong Baptist University, Kowloon Tong, 999077, Hong Kong, China.; Microlens Technologies, Beijing, 100086, China.
The development of a hook-like structure at the apical part of the soil-emerging organs has fascinated botanists for centuries, but how it is initiated remains unclear. Here, we demonstrate with high-throughput infrared imaging and 2-D clinostat treatment that, when gravity-induced root bending is absent, apical hook formation still takes place. In such scenarios, hook formation begins with a de novo growth asymmetry at the apical part of a straightly elongating hypocotyl. Remarkably, such de novo asymmetric growth, but not the following hook enlargement, precedes the establishment of a detectable auxin response asymmetry, and is largely independent of auxin biosynthesis, transport and signaling. Moreover, we found that functional cortical microtubule array is essential for the following enlargement of hook curvature. When microtubule array was disrupted by oryzalin, the polar localization of PIN proteins and the formation of an auxin maximum became impaired at the to-be-hook region. Taken together, we propose a more comprehensive model for apical hook initiation, in which the microtubule-dependent polar localization of PINs may mediate the instruction of growth asymmetry that is either stochastically took place, induced by gravitropic response, or both, to generate a significant auxin gradient that drives the full development of apical hook. This article is protected by copyright. All rights reserved.
PMID: 34786851
J Integr Plant Biol , IF:7.061 , 2021 Nov doi: 10.1111/jipb.13183
OsRLR4 binds to the OsAUX1 promoter to negatively regulate primary root development in rice.
Key Laboratory of Herbage & Endemic Crop Biology of Ministry of Education, Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, School of Life Sciences, Inner Mongolia University, Hohhot, 010000, China.; State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.; The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Lin'an Hangzhou, 311300, China.; State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310006, China.; College of Life Sciences and Oceanography, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen University, Shenzhen, China.; Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China.; State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.; Department of Biology, University of Fribourg, Rue Albert-Gockel 3, CH-1700, Fribourg, Switzerland.
Root architecture is one of the most important agronomic traits that determines rice crop yield. The primary root (PR) absorbs mineral nutrients and provides mechanical support; however, the molecular mechanisms of PR elongation remain unclear in rice. Here, the two loss-of-function T-DNA insertion mutants of root length regulator 4 (OsRLR4), osrlr4-1 and osrlr4-2 with longer PR, and three OsRLR4 overexpression lines, OE-OsRLR4-1/-2/-3 with shorter PR compared to the wild type, Hwayoung (WT/HY), were identified. OsRLR4 is one of five members of the PRAF subfamily of the regulator chromosome condensation 1 (RCC1) family. Phylogenetic analysis of OsRLR4 from wild and cultivated rice indicated that it is under selective sweeps, suggesting its potential role in domestication. OsRLR4 controls PR development by regulating auxin accumulation in the PR tip and thus the root apical meristem activity. A series of biochemical and genetic analyses demonstrated that OsRLR4 functions directly upstream of the auxin transporter OsAUX1. Moreover, OsRLR4 interacts with the TRITHORAX-like protein OsTrx1 to promote H3K4me3 deposition at the OsAUX1 promoter, thus altering its transcription level. This work provides insight into the cooperation of auxin and epigenetic modifications in regulating root architecture and provides a genetic resource for plant architecture breeding. This article is protected by copyright. All rights reserved.
PMID: 34726825
J Integr Plant Biol , IF:7.061 , 2021 Nov , V63 (11) : P1922-1936 doi: 10.1111/jipb.13171
Clathrin light chains regulate hypocotyl elongation by affecting the polarization of the auxin transporter PIN3 in Arabidopsis.
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.; College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China.; College of Life Sciences, Shaoxing University, Shaoxing, 312000, China.
PIN-FORMED (PIN)-dependent directional auxin transport is crucial for plant development. Although the redistribution of auxin mediated by the polarization of PIN3 plays key roles in modulating hypocotyl cell expansion, how PIN3 becomes repolarized to the proper sites within hypocotyl cells is poorly understood. We previously generated the clathrin light chain clc2-1 clc3-1 double mutant in Arabidopsis thaliana and found that it has an elongated hypocotyl phenotype compared to the wild type. Here, we performed genetic, cell biology, and pharmacological analyses combined with live-cell imaging to elucidate the molecular mechanism underlying the role of clathrin light chains in hypocotyl elongation. Our analyses indicated that the defects of the double mutant enhanced auxin maxima in epidermal cells, thus, promoting hypocotyl elongation. PIN3 relocated to the lateral sides of hypocotyl endodermal cells in clc2-1 clc3-1 mutants to redirect auxin toward the epidermal cell layers. Moreover, the loss of function of PIN3 largely suppressed the long hypocotyl phenotype of the clc2-1 clc3-1 double mutant, as did treatment with auxin transport inhibitors. Based on these data, we propose that clathrin modulates PIN3 abundance and polarity to direct auxin flux and inhibit cell elongation in the hypocotyl, providing novel insights into the regulation of hypocotyl elongation.
PMID: 34478221
Plant J , IF:6.417 , 2021 Nov doi: 10.1111/tpj.15609
Genetic variations in ZmSAUR15 contribute to the formation of immature embryo-derived embryonic calluses in maize.
State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Maize Research Institute, Sichuan Agricultural University, Chengdu, 611130, China.
The ability of immature maize embryos to form embryonic calluses (ECs) is highly genotype-dependent, which limits transgenic breeding development in maize. Here, we report the association mapping-based cloning of ZmSAUR15 using an association panel (AP) consisting of 309 inbred lines with diverse formation abilities of EC. We demonstrated that ZmSAUR15, which encodes a small auxin-upregulated RNA, acts as a negative effector in maize EC induction. Polymorphisms in the ZmSAUR15 promoter that influence the expression of ZmSAUR15 transcripts modulate the EC induction capacity in maize. ZmSAUR15 is involved in indole-3-acetic acid biosynthesis and cell division in immature embryo-derived callus. The ability of immature embryos to induce EC formation can be improved by the knockout of ZmSAUR15, which consequently increases the callus regeneration efficiency. Our study provides new insights into overcoming the genotypic limitations associated with EC formation and improving genetic transformation in maize.
PMID: 34822726
Plant J , IF:6.417 , 2021 Nov , V108 (4) : P1020-1036 doi: 10.1111/tpj.15489
Molecular mechanisms and hormonal regulation underpinning morphological dormancy: a case study using Apium graveolens (Apiaceae).
Department of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, UK.; Tozer Seeds, Tozer Seeds Ltd, Cobham, KT11 3EH, UK.; Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Faculty of Science, Palacky University Olomouc, Olomouc, CZ-78371, Czech Republic.; Swiss Light Source, Paul Scherrer Institute, Villigen, CH-5232, Switzerland.
Underdeveloped (small) embryos embedded in abundant endosperm tissue, and thus having morphological dormancy (MD) or morphophysiological dormancy (MPD), are considered to be the ancestral state in seed dormancy evolution. This trait is retained in the Apiaceae family, which provides excellent model systems for investigating the underpinning mechanisms. We investigated Apium graveolens (celery) MD by combined innovative imaging and embryo growth assays with the quantification of hormone metabolism, as well as the analysis of hormone and cell-wall related gene expression. The integrated experimental results demonstrated that embryo growth occurred inside imbibed celery fruits in association with endosperm degradation, and that a critical embryo size was required for radicle emergence. The regulation of these processes depends on gene expression leading to gibberellin and indole-3-acetic acid (IAA) production by the embryo and on crosstalk between the fruit compartments. ABA degradation associated with distinct spatiotemporal patterns in ABA sensitivity control embryo growth, endosperm breakdown and radicle emergence. This complex interaction between gibberellins, IAA and ABA metabolism, and changes in the tissue-specific sensitivities to these hormones is distinct from non-MD seeds. We conclude that the embryo growth to reach the critical size and the associated endosperm breakdown inside MD fruits constitute a unique germination programme.
PMID: 34510583
Int J Mol Sci , IF:5.923 , 2021 Nov , V22 (22) doi: 10.3390/ijms222212556
Genome-Wide Discovery of miRNAs with Differential Expression Patterns in Responses to Salinity in the Two Contrasting Wheat Cultivars.
Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China.; Key Laboratory of Crop Cultivation and Tillage, Agricultural College of Guangxi University, Nanning 530004, China.; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
Salinity is a serious environmental issue. It has a substantial effect on crop yield, as many crop species are sensitive to salinity due to climate change, and it impact is continuing to increase. Plant microRNAs (miRNAs) contribute to salinity stress response in bread wheat. However, the underlying molecular mechanisms by which miRNAs confer salt tolerance in wheat are unclear. We conducted a genome-wide discovery study using Illumina high throughput sequencing and comprehensive in silico analysis to obtain insight into the underlying mechanisms by which small RNAs confer tolerance to salinity in roots of two contrasting wheat cvv., namely Suntop (salt-tolerant) and Sunmate (salt-sensitive). A total of 191 microRNAs were identified in both cultivars, consisting of 110 known miRNAs and 81 novel miRNAs; 181 miRNAs were shared between the two cultivars. The known miRNAs belonged to 35 families consisted of 23 conserved and 12 unique families. Salinity stress induced 43 and 75 miRNAs in Suntop and Sunmate, respectively. Among them, 14 and 29 known and novel miRNAs were expressed in Suntop and 37 and 38 in Sunmate. In silico analysis revealed 861 putative target mRNAs for the 75 known miRNAs and 52 putative target mRNAs for the 15 candidate novel miRNAs. Furthermore, seven miRNAs including tae-miR156, tae-miR160, tae-miR171a-b, tae-miR319, tae-miR159a-b, tae-miR9657 and novel-mir59 that regulate auxin responsive-factor, SPL, SCL6, PCF5, R2R3 MYB, and CBL-CIPK, respectively, were predicted to contribute to salt tolerance in Suntop. This information helps further our understanding of how the molecular mechanisms of salt tolerance are mediated by miRNAs and may facilitate the genetic improvement of wheat cultivars.
PMID: 34830438
Int J Mol Sci , IF:5.923 , 2021 Nov , V22 (22) doi: 10.3390/ijms222212454
The Role of Plant Hormones in the Interaction of Colletotrichum Species with Their Host Plants.
Department of Applied Genetics and Cell Biology (DAGZ), Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna (BOKU), 3430 Tulln an der Donau, Austria.; Institute for Agribiotechnology Research (CIALE), Universidad de Salamanca, 37185 Salamanca, Spain.
Colletotrichum is a plant pathogenic fungus which is able to infect virtually every economically important plant species. Up to now no common infection mechanism has been identified comparing different plant and Colletotrichum species. Plant hormones play a crucial role in plant-pathogen interactions regardless whether they are symbiotic or pathogenic. In this review we analyze the role of ethylene, abscisic acid, jasmonic acid, auxin and salicylic acid during Colletotrichum infections. Different Colletotrichum strains are capable of auxin production and this might contribute to virulence. In this review the role of different plant hormones in plant-Colletotrichum interactions will be discussed and thereby auxin biosynthetic pathways in Colletotrichum spp. will be proposed.
PMID: 34830343
Int J Mol Sci , IF:5.923 , 2021 Nov , V22 (22) doi: 10.3390/ijms222212369
Auxin Metabolite Profiling in Isolated and Intact Plant Nuclei.
Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences and Faculty of Science, Palacky University, Slechtitelu 27, CZ-78371 Olomouc, Czech Republic.; Institute of Experimental Botany of the Czech Academy of Sciences, Centre of the Region Hana for Biotechnological and Agricultural Research, Slechtitelu 31, CZ-77900 Olomouc, Czech Republic.; Department of Biotechnology, The Franciszek Gorski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Krakow, Poland.; Department of Botany, Faculty of Science, Palacky University, Slechtitelu 27, CZ-78371 Olomouc, Czech Republic.; School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK.
The plant nucleus plays an irreplaceable role in cellular control and regulation by auxin (indole-3-acetic acid, IAA) mainly because canonical auxin signaling takes place here. Auxin can enter the nucleus from either the endoplasmic reticulum or cytosol. Therefore, new information about the auxin metabolome (auxinome) in the nucleus can illuminate our understanding of subcellular auxin homeostasis. Different methods of nuclear isolation from various plant tissues have been described previously, but information about auxin metabolite levels in nuclei is still fragmented and insufficient. Herein, we tested several published nucleus isolation protocols based on differential centrifugation or flow cytometry. The optimized sorting protocol leading to promising yield, intactness, and purity was then combined with an ultra-sensitive mass spectrometry analysis. Using this approach, we can present the first complex report on the auxinome of isolated nuclei from cell cultures of Arabidopsis and tobacco. Moreover, our results show dynamic changes in auxin homeostasis at the intranuclear level after treatment of protoplasts with free IAA, or indole as a precursor of auxin biosynthesis. Finally, we can conclude that the methodological procedure combining flow cytometry and mass spectrometry offers new horizons for the study of auxin homeostasis at the subcellular level.
PMID: 34830250
Int J Mol Sci , IF:5.923 , 2021 Nov , V22 (22) doi: 10.3390/ijms222212336
Genome-Wide Comprehensive Analysis of the GASA Gene Family in Populus.
National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China.; Salver Academy of Botany, Rizhao 276800, China.
Gibberellic acid-stimulated Arabidopsis (GASA) proteins, as cysteine-rich peptides (CRPs), play roles in development and reproduction and biotic and abiotic stresses. Although the GASA gene family has been identified in plants, the knowledge about GASAs in Populus euphratica, the woody model plant for studying abiotic stress, remains limited. Here, we referenced the well-sequenced Populus trichocarpa genome, and identified the GASAs in the whole genome of P. euphratica and P. trichocarpa. 21 candidate genes in P. trichocarpa and 19 candidate genes in P. euphratica were identified and categorized into three subfamilies by phylogenetic analysis. Most GASAs with signal peptides were located extracellularly. The GASA genes in Populus have experienced multiple gene duplication events, especially in the subfamily A. The evolution of the subfamily A, with the largest number of members, can be attributed to whole-genome duplication (WGD) and tandem duplication (TD). Collinearity analysis showed that WGD genes played a leading role in the evolution of GASA genes subfamily B. The expression patterns of P. trichocarpa and P. euphratica were investigated using the PlantGenIE database and the real-time quantitative PCR (qRT-PCR), respectively. GASA genes in P. trichocarpa and P. euphratica were mainly expressed in young tissues and organs, and almost rarely expressed in mature leaves. GASA genes in P. euphratica leaves were also widely involved in hormone responses and drought stress responses. GUS activity assay showed that PeuGASA15 was widely present in various organs of the plant, especially in vascular bundles, and was induced by auxin and inhibited by mannitol dramatically. In summary, this present study provides a theoretical foundation for further research on the function of GASA genes in P. euphratica.
PMID: 34830215
Int J Mol Sci , IF:5.923 , 2021 Nov , V22 (22) doi: 10.3390/ijms222212328
Garlic Volatile Diallyl Disulfide Induced Cucumber Resistance to Downy Mildew.
College of Horticulture, Northwest A&F University, Xianyang 712100, China.
Allicin compositions in garlic are used widely as fungicides in modern agriculture, in which diallyl disulfide (DADS) is a major compound. Downy mildew, caused by Pseudoperonospora cubensis (P. cubensis), is one of the most destructive diseases and causes severe yield losses in cucumbers. To explore the potential mechanism of DADS-induced cucumber resistance to downy mildew, cucumber seedlings were treated with DADS and then inoculated with P. cubensis at a 10-day interval. Symptom observation showed that DADS significantly induced cucumber resistance to downy mildew. Furthermore, both lignin and H2O2 were significantly increased by DADS treatment to responding P. cubensis infection. Simultaneously, the enzyme activities of peroxidase (POD) in DADS-treated seedlings were significantly promoted. Meanwhile, both the auxin (IAA) and salicylic acid (SA) contents were increased, and their related differentially expressed genes (DEGs) were up-regulated when treated with DADS. Transcriptome profiling showed that many DEGs were involved in the biological processes of defense responses, in which DEGs on the pathways of 'phenylpropanoid biosynthesis', 'phenylalanine metabolism', 'MAPK signaling', and 'plant hormone signal transduction' were significantly up-regulated in DADS-treated cucumbers uninoculated with the pathogen. Based on the results of several physiological indices and transcriptomes, a potential molecular mechanism of DADS-induced cucumber resistance to downy mildew was proposed and discussed. The results of this study might give new insight into the exploration of the induced resistance mechanism of cucumber to downy mildew and provide useful information for the subsequent mining of resistance genes in cucumber.
PMID: 34830208
Int J Mol Sci , IF:5.923 , 2021 Nov , V22 (22) doi: 10.3390/ijms222212258
Mixed Transcriptome Analysis Revealed the Possible Interaction Mechanisms between Zizania latifolia and Ustilago esculenta Inducing Jiaobai Stem-Gall Formation.
College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.; Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College, Yangzhou University, Yangzhou 225009, China.
The smut fungus Ustilago esculenta infects Zizania latifolia and induces stem expansion to form a unique vegetable named Jiaobai. Although previous studies have demonstrated that hormonal control is essential for triggering stem swelling, the role of hormones synthesized by Z. latifolia and U. esculenta and the underlying molecular mechanism are not yet clear. To study the mechanism that triggers swollen stem formation, we analyzed the gene expression pattern of both interacting organisms during the initial trigger of culm gall formation, at which time the infective hyphae also propagated extensively and penetrated host stem cells. Transcriptional analysis indicated that abundant genes involving fungal pathogenicity and plant resistance were reprogrammed to maintain the subtle balance between the parasite and host. In addition, the expression of genes involved in auxin biosynthesis of U. esculenta obviously decreased during stem swelling, while a large number of genes related to the synthesis, metabolism and signal transduction of hormones of the host plant were stimulated and showed specific expression patterns, particularly, the expression of ZlYUCCA9 (a flavin monooxygenase, the key enzyme in indole-3-acetic acid (IAA) biosynthesis pathway) increased significantly. Simultaneously, the content of IAA increased significantly, while the contents of cytokinin and gibberellin showed the opposite trend. We speculated that auxin produced by the host plant, rather than the fungus, triggers stem swelling. Furthermore, from the differently expressed genes, two candidate Cys2-His2 (C2H2) zinc finger proteins, GME3058_g and GME5963_g, were identified from U. esculenta, which may conduct fungus growth and infection at the initial stage of stem-gall formation.
PMID: 34830140
Int J Mol Sci , IF:5.923 , 2021 Nov , V22 (22) doi: 10.3390/ijms222212130
Global Transcriptomic Analysis Reveals Differentially Expressed Genes Involved in Embryogenic Callus Induction in Drumstick (Moringa oleifera Lam.).
Department of Forestry, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, Guangzhou 510642, China.; Guangdong Province Research Center of Woody Forage Engineering Technology, Guangzhou 510642, China.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China.
The plant embryogenic callus (EC) is an irregular embryogenic cell mass with strong regenerative ability that can be used for propagation and genetic transformation. However, difficulties with EC induction have hindered the breeding of drumstick, a tree with diverse potential commercial uses. In this study, three drumstick EC cDNA libraries were sequenced using an Illumina NovaSeq 6000 system. A total of 7191 differentially expressed genes (DEGs) for embryogenic callus development were identified, of which 2325 were mapped to the KEGG database, with the categories of plant hormone signal transduction and Plant-pathogen interaction being well-represented. The results obtained suggest that auxin and cytokinin metabolism and several embryogenesis-labeled genes are involved in embryogenic callus induction. Additionally, 589 transcription factors from 20 different families were differentially expressed during EC formation. The differential expression of 16 unigenes related to auxin signaling pathways was validated experimentally by quantitative real time PCR (qRT-PCR) using samples representing three sequential developmental stages of drumstick EC, supporting their apparent involvement in drumstick EC formation. Our study provides valuable information about the molecular mechanism of EC formation and has revealed new genes involved in this process.
PMID: 34830008
Int J Mol Sci , IF:5.923 , 2021 Nov , V22 (21) doi: 10.3390/ijms222111968
Genome-Wide Identification of ARF Gene Family Suggests a Functional Expression Pattern during Fruitlet Abscission in Prunus avium L.
Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Collaborative Innovation Center for Mountain Ecology & Agro-Bioengineering (CICMEAB), Institute of Agro-Bioengineering/College of Life Sciences, Guizhou University, Guiyang 550025, China.; College of Forestry, Guizhou University/Institute for Forest Resources & Environment of Guizhou, Guiyang 550025, China.
Auxin response factors (ARFs) play a vital role in plant growth and development. In the current study, 16 ARF members have been identified in the sweet cherry (Prunus avium L.) genome. These genes are all located in the nucleus. Sequence analysis showed that genes in the same subgroup have similar exon-intron structures. A phylogenetic tree has been divided into five groups. The promoter sequence includes six kinds of plant hormone-related elements, as well as abiotic stress response elements such as low temperature or drought. The expression patterns of PavARF in different tissues, fruitlet abscission, cold and drought treatment were comprehensively analyzed. PavARF10/13 was up-regulated and PavARF4/7/11/12/15 was down-regulated in fruitlet abscising. These genes may be involved in the regulation of fruit drop in sweet cherry fruits. This study comprehensively analyzed the bioinformatics and expression pattern of PavARF, which can lay the foundation for further understanding the PavARF family in plant growth development and fruit abscission.
PMID: 34769398
Mol Plant Pathol , IF:5.663 , 2021 Nov , V22 (11) : P1449-1458 doi: 10.1111/mpp.13122
Manipulation of auxin signalling by plant viruses.
Department of Phytopathology, Institute of Sugar Beet Research, Gottingen, Germany.; Department of Plant Biology, Uppsala BioCenter SLU, Swedish University of Agricultural Sciences, Linnean Center for Plant Biology, Uppsala, Sweden.
Compatible plant-virus interactions result in dramatic changes of the plant transcriptome and morphogenesis, and are often associated with rapid alterations in plant hormone homeostasis and signalling. Auxin controls many aspects of plant organogenesis, development, and growth; therefore, plants can rapidly perceive and respond to changes in the cellular auxin levels. Auxin signalling is a tightly controlled process and, hence, is highly vulnerable to changes in the mRNA and protein levels of its components. There are several core nuclear components of auxin signalling. In the nucleus, the interaction of auxin response factors (ARFs) and auxin/indole acetic acid (Aux/IAA) proteins is essential for the control of auxin-regulated pathways. Aux/IAA proteins are negative regulators, whereas ARFs are positive regulators of the auxin response. The interplay between both is essential for the transcriptional regulation of auxin-responsive genes, which primarily regulate developmental processes but also modulate the plant immune system. Recent studies suggest that plant viruses belonging to different families have developed various strategies to disrupt auxin signalling, namely by (a) changing the subcellular localization of Aux/IAAs, (b) preventing degradation of Aux/IAAs by stabilization, or (c) inhibiting the transcriptional activity of ARFs. These interactions perturb auxin signalling and experimental evidence from various studies highlights their importance for virus replication, systemic movement, interaction with vectors for efficient transmission, and symptom development. In this microreview, we summarize and discuss the current knowledge on the interaction of plant viruses with auxin signalling components of their hosts.
PMID: 34420252
iScience , IF:5.458 , 2021 Nov , V24 (11) : P103236 doi: 10.1016/j.isci.2021.103236
SDG2 regulates Arabidopsis inflorescence architecture through SWR1-ERECTA signaling pathway.
College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, China.
Inflorescence architecture is diverse in flowering plants, and two determinants of inflorescence architecture are the inflorescence meristem and pedicel length. Although the ERECTA (ER) signaling pathway, in coordination with the SWR1 chromatin remodeling complex, regulates inflorescence architecture with subsequent effects on pedicel elongation, the mechanism underlying SWR1-ER signaling pathway regulation of inflorescence architecture remains unclear. This study determined that SDG2 genetically interacts with the SWR1-ER signaling pathways in regulating inflorescence architecture. Transcriptome results showed that auxin might potentially influence inflorescence growth mediated by SDG2 and SWR1-ER pathways. SWR1 and ER signaling are required to enrich H2A.Z histone variant and SDG2 regulated SDG2-mediated H3K4me3 histone modification at auxin-related genes and H2A.Z histone variant enrichment. Our study shows how the regulation of inflorescence architecture is mediated by SDG2 and SWR1-ER, which affects auxin hormone signaling pathways.
PMID: 34746701
iScience , IF:5.458 , 2021 Nov , V24 (11) : P103228 doi: 10.1016/j.isci.2021.103228
MYB70 modulates seed germination and root system development in Arabidopsis.
CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China.; Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla 666303, China.; College of Horticulture, Shanxi Agricultural University, Taigu 030801, China.; State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China.; Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam.; Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA.
Crosstalk among ABA, auxin, and ROS plays critical roles in modulating seed germination, root growth, and suberization. However, the underlying molecular mechanisms remain largely elusive. Here, MYB70, a R2R3-MYB transcription factor was shown to be a key component of these processes in Arabidopsis thaliana. myb70 seeds displayed decreased sensitivity, while MYB70-overexpressing OX70 seeds showed increased sensitivity in germination in response to exogenous ABA through MYB70 physical interaction with ABI5 protein, leading to enhanced stabilization of ABI5. Furthermore, MYB70 modulates root system development (RSA) which is associated with increased conjugated IAA content and H2O2/O2 (-) ratio but reduced root suberin deposition, consequently affecting nutrient uptake. In support of these data, MYB70 positively regulates the expression of auxin conjugation-related GH3, while negatively peroxidase-encoding and suberin biosynthesis-related genes. Our findings collectively revealed a previously uncharacterized component that modulates ABA and auxin signaling pathways, H2O2/O2 (-) balance, and suberization, consequently regulating RSA and seed germination.
PMID: 34746697
Plant Cell Physiol , IF:4.927 , 2021 Nov , V62 (8) : P1335-1354 doi: 10.1093/pcp/pcab101
Transcriptome Dynamics of Epidermal Reprogramming during Direct Shoot Regeneration in Torenia fournieri.
Botanical Gardens, Graduate School of Science, The University of Tokyo, 3-7-1 Hakusan, Bunkyo-ku, Tokyo 112-0001, Japan.; Center for Sustainable Resource Science, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.; Department of Biology, Graduate School of Science, Kobe University, Rokkodai-cho 1-1, Nada-ku, Kobe, Hyogo 657-8501, Japan.; Health and Crop Sciences Research Laboratory, Sumitomo Chemical Co. Ltd., 4-2-1 Takatsukasa, Takarazuka, Hyogo 665-8555, Japan.; Department of Biological Science, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka 259-1293, Japan.; Department of Biological Chemistry, College of Bioscience Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.; Department of Biology, Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan.; Institute of Transformative Bio-Molecules (WPI-ITbM), Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan.; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Shoot regeneration involves reprogramming of somatic cells and de novo organization of shoot apical meristems (SAMs). In the best-studied model system of shoot regeneration using Arabidopsis, regeneration is mediated by the auxin-responsive pluripotent callus formation from pericycle or pericycle-like tissues according to the lateral root development pathway. In contrast, shoot regeneration can be induced directly from fully differentiated epidermal cells of stem explants of Torenia fournieri (Torenia), without intervening the callus mass formation in culture with cytokinin; yet, its molecular mechanisms remain unaddressed. Here, we characterized this direct shoot regeneration by cytological observation and transcriptome analyses. The results showed that the gene expression profile rapidly changes upon culture to acquire a mixed signature of multiple organs/tissues, possibly associated with epidermal reprogramming. Comparison of transcriptomes between three different callus-inducing cultures (callus induction by auxin, callus induction by wounding and protoplast culture) of Arabidopsis and the Torenia stem culture identified genes upregulated in all the four culture systems as candidates of common factors of cell reprogramming. These initial changes proceeded independently of cytokinin, followed by cytokinin-dependent, transcriptional activations of nucleolar development and cell cycle. Later, SAM regulatory genes became highly expressed, leading to SAM organization in the foci of proliferating cells in the epidermal layer. Our findings revealed three distinct phases with different transcriptomic and regulatory features during direct shoot regeneration from the epidermis in Torenia, which provides a basis for further investigation of shoot regeneration in this unique culture system.
PMID: 34223624
Plant Sci , IF:4.729 , 2021 Nov , V312 : P111044 doi: 10.1016/j.plantsci.2021.111044
PIN3-mediated auxin transport contributes to blue light-induced adventitious root formation in Arabidopsis.
State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.; Institute of Crop Science of Wuhan Academy of Agriculture Science, Wuhan, 430345, China.; State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China. Electronic address: yuantingting@whu.edu.cn.
Adventitious rooting is a heritable quantitative trait that is influenced by multiple endogenous and exogenous factors in plants, and one important environmental factor required for efficient adventitious root formation is light signaling. However, the physiological significance and molecular mechanism of light underlying adventitious root formation are still largely unexplored. Here, we report that blue light-induced adventitious root formation is regulated by PIN-FORMED3 (PIN3)-mediated auxin transport in Arabidopsis. Adventitious root formation is significantly impaired in the loss-of-function mutants of the blue light receptors, PHOTOROPIN1 (PHOT1) and PHOTOROPIN2 (PHOT2), as well as the phototropic transducer, NON-PHOTOTROPIC HYPOCOTYL3 (NPH3). In addition, blue light enhanced the auxin content in the adventitious root, and the pin3 loss-of-function mutant had a reduced adventitious rooting response under blue light compared to the wild type. The PIN3 protein level was higher in plants treated with blue light than in those in darkness, especially in the hypocotyl pericycle, while PIN3-GFP failed to accumulate in nph3 PIN3::PIN3-GFP. Furthermore, the results showed that PIN3 physically interacted with NPH3, a key transducer in phototropic signaling. Taken together, our study demonstrates that blue light induces adventitious root formation through the phototropic signal transducer, NPH3, which regulates adventitious root formation by affecting PIN3-mediated auxin transport.
PMID: 34620442
BMC Plant Biol , IF:4.215 , 2021 Nov , V21 (1) : P524 doi: 10.1186/s12870-021-03294-x
Ectopic expression of TaBG1 increases seed size and alters nutritional characteristics of the grain in wheat but does not lead to increased yields.
NIAB, 93 Lawrence Weaver Road, Cambridge, CB3 0LE, UK. matthew.milner@niab.com.; NIAB, 93 Lawrence Weaver Road, Cambridge, CB3 0LE, UK.
BACKGROUND: Grain size is thought to be a major component of yield in many plant species. Here we set out to understand if knowledge from other cereals such as rice could translate to increased yield gains in wheat and lead to increased nitrogen use efficiency. Previous findings that the overexpression of OsBG1 in rice increased yields while increasing seed size suggest translating gains from rice to other cereals may help to increase yields. RESULTS: The orthologous genes of OsBG1 were identified in wheat. One homoeologous wheat gene was cloned and overexpressed in wheat to understand its role in controlling seed size. Potential alteration in the nutritional profile of the grains were also analyzed in wheat overexpressing TaBG1. It was found that increased TaBG1-A expression could indeed lead to larger seed size but was linked to a reduction in seed number per plant leading to no significant overall increase in yield. Other important components of yield such as biomass or tillering did not change significantly with increased TaBG1-A expression. The nutritional profile of the grain was altered, with a significant decrease in the Zn levels in the grain associated with increased seed size, but Fe and Mn concentrations were unchanged. Protein content of the wheat grain also fell under moderate N fertilization levels but not under deficient or adequate levels of N. CONCLUSIONS: TaBG1 does control seed size in wheat but increasing the seed size per se does not increase yield and may come at the cost of lower concentrations of essential elements as well as potentially lower protein content. Nevertheless, TaBG1 could be a useful target for further breeding efforts in combination with other genes for increased biomass.
PMID: 34758742
BMC Plant Biol , IF:4.215 , 2021 Nov , V21 (1) : P514 doi: 10.1186/s12870-021-03276-z
Comparative transcriptome analysis of coleorhiza development in japonica and Indica rice.
Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, China.; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, 518057, China.; Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Agriculture, Hunan Agricultural University, Changsha, 410128, China.; Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong.; CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, 518057, China. yangfeng881102@126.com.; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, 518057, China. jzhang@hkbu.edu.hk.; Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong. jzhang@hkbu.edu.hk.; School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong. jzhang@hkbu.edu.hk.
BACKGROUND: Coleorhiza hairs, are sheath-like outgrowth organs in the seeds of Poaceae family that look like root hair but develop from the coleorhiza epidermal cells during seed imbibition. The major role of coleorhiza hair in seed germination involves facilitating water uptake and nutrient supply for seed germination. However, molecular basis of coleorhiza hair development and underlying genes and metabolic pathways during seed germination are largely unknown and need to be established. RESULTS: In this study, a comparative transcriptome analysis of coleorhiza hairs from japonica and indica rice suggested that DEGs in embryo samples from seeds with embryo in air (EIA) as compared to embryo from seeds completely covered by water (CBW) were enriched in water deprivation, abscisic acid (ABA) and auxin metabolism, carbohydrate catabolism and phosphorus metabolism in coleorhiza hairs in both cultivars. Up-regulation of key metabolic genes in ABA, auxin and dehydrin and aquaporin genes may help maintain the basic development of coleorhiza hair in japonica and indica in EIA samples during both early and late stages. Additionally, DEGs involved in glutathione metabolism and carbon metabolism are upregulated while DEGs involved in amino acid and nucleotide sugar metabolism are downregulated in EIA suggesting induction of oxidative stress-alleviating genes and less priority to primary metabolism. CONCLUSIONS: Taken together, results in this study could provide novel aspects about the molecular signaling that could be involved in coleorhiza hair development in different types of rice cultivars during seed germination and may give some hints for breeders to improve seed germination efficiency under moderate drought conditions.
PMID: 34736393
BMC Plant Biol , IF:4.215 , 2021 Nov , V21 (1) : P510 doi: 10.1186/s12870-021-03283-0
Genome and transcriptome-based characterization of high energy carbon-ion beam irradiation induced delayed flower senescence mutant in Lotus japonicus.
Biophysics Group, Biomedical Center, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, People's Republic of China.; University of Chinese Academy of Sciences, Beijing, 100000, People's Republic of China.; Guangdong Key Laboratory for New Technology Research of Vegetables, Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, Guangdong, China.; School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, 730000, People's Republic of China.; Kejin Innovation Institute of Heavy Ion Beam Biological Industry, Baiyin, 730900, People's Republic of China.; Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100000, People's Republic of China.; Biophysics Group, Biomedical Center, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, People's Republic of China. libinzhou@impcas.ac.cn.; University of Chinese Academy of Sciences, Beijing, 100000, People's Republic of China. libinzhou@impcas.ac.cn.; Kejin Innovation Institute of Heavy Ion Beam Biological Industry, Baiyin, 730900, People's Republic of China. libinzhou@impcas.ac.cn.
BACKGROUND: Flower longevity is closely related to pollen dispersal and reproductive success in all plants, as well as the commercial value of ornamental plants. Mutants that display variation in flower longevity are useful tools for understanding the mechanisms underlying this trait. Heavy-ion beam irradiation has great potential to improve flower shapes and colors; however, few studies are available on the mutation of flower senescence in leguminous plants. RESULTS: A mutant (C416) exhibiting blossom duration eight times longer than that of the wild type (WT) was isolated in Lotus japonicus derived from carbon ion beam irradiation. Genetic assays supported that the delayed flower senescence of C416 was a dominant trait controlled by a single gene, which was located between 4,616,611 Mb and 5,331,876 Mb on chromosome III. By using a sorting strategy of multi-sample parallel genome sequencing, candidate genes were narrowed to the gene CUFF.40834, which exhibited high identity to ethylene receptor 1 in other model plants. A physiological assay demonstrated that C416 was insensitive to ethylene precursor. Furthermore, the dynamic changes of phytohormone regulatory network in petals at different developmental stages was compared by using RNA-seq. In brief, the ethylene, jasmonic acid (JA), and salicylic acid (SA) signaling pathways were negatively regulated in C416, whereas the brassinosteroid (BR) and cytokinin signaling pathways were positively regulated, and auxin exhibited dual effects on flower senescence in Lotus japonicus. The abscisic acid (ABA) signaling pathway is positively regulated in C416. CONCLUSION: So far, C416 might be the first reported mutant carrying a mutation in an endogenous ethylene-related gene in Lotus japonicus, rather than through the introduction of exogenous genes by transgenic techniques. A schematic of the flower senescence of Lotus japonicus from the perspective of the phytohormone regulatory network was provided based on transcriptome profiling of petals at different developmental stages. This study is informative for elucidating the molecular mechanism of delayed flower senescence in C416, and lays a foundation for candidate flower senescence gene identification in Lotus japonicus. It also provides another perspective for the improvement of flower longevity in legume plants by heavy-ion beam.
PMID: 34732128
BMC Genomics , IF:3.969 , 2021 Nov , V22 (1) : P806 doi: 10.1186/s12864-021-08087-y
Characterization of phytohormone and transcriptome profiles during protocorm-like bodies development of Paphiopedilum.
Key Laboratory of South China Agricultural Plant Molecular Analysis and Gene Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.; University of Chinese Academy of Sciences, Beijing, 100049, China.; Key Laboratory of South China Agricultural Plant Molecular Analysis and Gene Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China. zengsongjun@scib.ac.cn.; Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650, China. zengsongjun@scib.ac.cn.; Key Laboratory of South China Agricultural Plant Molecular Analysis and Gene Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China. linfang@scbg.ac.cn.; Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China. linfang@scbg.ac.cn.
BACKGROUND: Paphiopedilum, commonly known as slipper orchid, is an important genus of orchid family with prominent horticultural value. Compared with conventional methods such as tillers and in vitro shoots multiplication, induction and regeneration of protocorm-like bodies (PLBs) is an effective micropropagation method in Paphiopedilum. The PLB initiation efficiency varies among species, hybrids and varieties, which leads to only a few Paphiopedilum species can be large-scale propagated through PLBs. So far, little is known about the mechanisms behind the initiation and maintenance of PLB in Paphiopedilum. RESULTS: A protocol to induce PLB development from seed-derived protocorms of Paphiopedilum SCBG Huihuang90 (P. SCBG Prince x P. SCBG Miracle) was established. The morphological characterization of four key PLB developmental stages showed that significant polarity and cell size gradients were observed within each PLB. The endogenous hormone level was evaluated. The increase in the levels of indoleacetic acid (IAA) and jasmonic acid (JA) accompanying the PLBs differentiation, suggesting auxin and JA levels were correlated with PLB development. Gibberellic acid (GA) decreased to a very low level, indicated that GA inactivation may be necessary for shoot apical meristem (SAM) development. Comparative transcriptomic profiles of four different developmental stages of P. SCBG Huihuang90 PLBs explore key genes involved in PLB development. The numbers of differentially expressed genes (DEGs) in three pairwise comparisons (A vs B, B vs C, C vs D) were 1455, 349, and 3529, respectively. KEGG enrichment analysis revealed that DEGs were implicated in secondary metabolite metabolism and photosynthesis. DEGs related to hormone metabolism and signaling, somatic embryogenesis, shoot development and photosynthesis were discussed in detail. CONCLUSION: This study is the first report on PLB development in Paphiopedilum using transcriptome sequencing, which provides useful information to understand the mechanisms of PLB development.
PMID: 34749655
Pestic Biochem Physiol , IF:3.963 , 2021 Nov , V179 : P104978 doi: 10.1016/j.pestbp.2021.104978
The phytotoxicity mechanism of florpyrauxifen-benzyl to Echinochloa crus-galli (L.) P. Beauv and weed control effect.
Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, 210095 Nanjing, China; State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, 210095 Nanjing, China.; Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, 210095 Nanjing, China; State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, 210095 Nanjing, China. Electronic address: dly@njau.edu.cn.
Weeds infest rice causing high yield losses, leading to the increasing use of herbicides for weed control. However, many weeds have evolved resistance to common commercial herbicides, including penoxsulam, metamifop and quinclorac. This study investigated the weed control effect and the phytotoxicity mechanism of florpyrauxifen-benzyl, a novel synthetic auxin herbicide registered for weed management in rice fields in China. The greenhouse study showed that florpyrauxifen-benzyl was highly efficient (GR50 < 6 and GR90 < 15 g a.i ha(-1)) at controlling 10 weed species commonly found in rice fields, including penoxsulam- and quinclorac- resistant(R) biotypes of Echinochloa Beauv. and bensulfuron-methyl-R biotype of Ammannia arenaria. The typical plant hormone content showed that following florpyrauxifen-benzyl treatment, indole-3-acetic acid (IAA) production changed only slightly at 12 h, while abscisic acid (ABA) production increased with time in the treated group, whose content was significantly higher than that of the control. Besides, ethylene biosynthesis was stimulated by florpyrauxifen-benzyl, ethylene production, 1-aminocyclopropane-1-carboxylic acid (ACC) content, and 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxidase (ACO) activities, which evidently increased in the treated group, and ethylene peaked at 36 h. For the antioxidant enzyme activities and malondialdehyde (MDA) content in the treated group, results showed that MDA content continuously increased with time and was greater than that in the untreated group at 48 h and 72 h, superoxide dismutase (SOD) activity changed with exposure time and was significantly higher in the treatment group than the control at 48 h. A similar phenomenon was observed in peroxidase (POD) activity, which reached a peak at 48 h, and no distinct difference in catalase (CAT) activity was observed among groups except for the higher activity in the treated groups than control at 36 h and 48 h. Our results showed that that the stimulation ethylene biosynthesis and accumulation of ABA and reactive oxygen species (ROS) play important roles in the phytotoxicity mechanism of florpyrauxifen-benzyl in plants. Our findings demonstrate the potential of florpyrauxifen-benzyl to provide an alternative weed management strategy for rice fields.
PMID: 34802528
Plants (Basel) , IF:3.935 , 2021 Nov , V10 (11) doi: 10.3390/plants10112517
Nanopore-Based Comparative Transcriptome Analysis Reveals the Potential Mechanism of High-Temperature Tolerance in Cotton (Gossypium hirsutum L.).
Engineering Research Centre of Cotton of Ministry of Education, Xinjiang Agricultural University, 311 Nongda East Road, Urumqi 830001, China.; Xinjiang Academy of Agricultural Science, Urumqi 830001, China.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.; Adsen Biotechnology Co., Ltd., Urumqi 830022, China.
Extreme high temperatures are threatening cotton production around the world due to the intensification of global warming. To cope with high-temperature stress, heat-tolerant cotton cultivars have been bred, but the heat-tolerant mechanism remains unclear. This study selected heat-tolerant ('Xinluzao36') and heat-sensitive ('Che61-72') cultivars of cotton treated with high-temperature stress as plant materials and performed comparative nanopore sequencing transcriptome analysis to reveal the potential heat-tolerant mechanism of cotton. Results showed that 120,605 nonredundant sequences were generated from the raw reads, and 78,601 genes were annotated. Differentially expressed gene (DEG) analysis showed that a total of 19,600 DEGs were screened; the DEGs involved in the ribosome, heat shock proteins, auxin and ethylene signaling transduction, and photosynthesis pathways may be attributed to the heat tolerance of the heat-tolerant cotton cultivar. This study also predicted a total of 5118 long non-coding RNAs (lncRNAs)and 24,462 corresponding target genes. Analysis of the target genes revealed that the expression of some ribosomal, heat shock, auxin and ethylene signaling transduction-related and photosynthetic proteins may be regulated by lncRNAs and further participate in the heat tolerance of cotton. This study deepens our understandings of the heat tolerance of cotton.
PMID: 34834881
Plants (Basel) , IF:3.935 , 2021 Nov , V10 (11) doi: 10.3390/plants10112503
Effects of Exogenous Application of Indole-3-Butyric Acid on Maize Plants Cultivated in the Presence or Absence of Cadmium.
Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dubravska cesta 9, 845 23 Bratislava, Slovakia.; Institute of Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, 845 38 Bratislava, Slovakia.
Auxins are plant hormones that affect plant growth, development, and improve a plant's tolerance to stress. In this study, we found that the application of indole-3-butyric acid (IBA) had diverse effects on the growth of maize (Zea mays L.) roots treated without/with Cd. IBA caused changes in the growth and morphology of the roots under non-stress conditions; hence, we were able to select two concentrations of IBA (10(-11) M as stimulatory and 10(-7) M as inhibitory). IBA in stimulatory concentration did not affect the concentration of H2O2 or the activity of antioxidant enzymes while IBA in inhibitory concentration increased only the concentration of H2O2 (40.6%). The application of IBA also affected the concentrations of mineral nutrients. IBA in stimulatory concentration increased the concentration of N, K, Ca, S, and Zn (5.8-14.8%) and in inhibitory concentration decreased concentration of P, K, Ca, S, Fe, Mn, Zn, and Cu (5.5-36.6%). Moreover, IBA in the concentration 10(-9) M had the most positive effects on the plants cultivated with Cd. It decreased the concentration of H2O2 (34.3%), the activity of antioxidant enzymes (23.7-36.4%), and increased the concentration of all followed elements, except Mg (5.5-34.1%), when compared to the Cd.
PMID: 34834862
Plants (Basel) , IF:3.935 , 2021 Nov , V10 (11) doi: 10.3390/plants10112380
Unravelling the Molecular Regulation Mechanisms of Slow Ripening Trait in Prunus persica.
Escuela de Agronomia, Facultad de Ciencias Agronomicas y de los Alimentos, Pontificia Universidad Catolica de Valparaiso, Calle San Francisco s/n, La Palma, Quillota 2260000, Chile.; Centro de Biotecnologia Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370186, Chile.; Centro de Estudios Postcosecha, Facultad de Ciencias Agronomicas, Universidad de Chile, Santiago 8820808, Chile.
Fruit development is a complex process that involves the interplay of cell division, expansion, and differentiation. As a model to study fruit development, nectarines incapable of ripening were described as slow ripening. Slow ripening fruits remained firm and exhibited no rise in CO2 or ethylene production rates for one month or more at 20 degrees C. Different studies suggest that this trait is controlled by a single gene (NAC072). Transcriptome analysis between normal and slow ripening fruits showed a total of 157, 269, 976, and 5.224 differentially expressed genes in each fruit developmental stage analyzed (T1, T2, T3, and T7, respectively), and no expression of NAC072 was found in the slow ripening individuals. Using this transcriptomic information, we identified a correlation of NAC072 with auxin-related genes and two genes associated with terpene biosynthesis. On the other hand, significant differences were observed in hormonal biosynthetic pathways during fruit development between the normal and slow ripening individuals (gibberellin, ethylene, jasmonic acid and abscisic acid). These results suggest that the absence of NAC072 by the direct or indirect expression control of auxins or terpene-related genes prevents normal peach fruit development.
PMID: 34834743
J Plant Physiol , IF:3.549 , 2021 Nov , V268 : P153562 doi: 10.1016/j.jplph.2021.153562
Higher nitrogen content and auxin export from rice tiller enhance low-ammonium-dependent tiller outgrowth.
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, 210095, China.; 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, 210095, China. Electronic address: ylzhang@njau.edu.cn.
In the early growth stage, nutrient uptake by rice roots is weak. However, rice tillering at this stage would require high N input. Thus, it is vital to clarify the mechanism involved in tillering capacity with low N inputs. In this report, two widely-planted japonica cultivars (cvs Yangyujing 2 and Nanjing 45) were selected mainly because, unlike cv. Nanjing 45, cv. Yangyujing 2 shows low-N-induced tiller outgrowth. Responses of tillers in two rice cultivars to mixture of N forms versus sole NH4(+) supply were similar, suggesting that NH4(+) plays a pivotal role in N-modulated rice tillering. Under low NH4(+) supply, higher expression of OsAMT1.2, OsAMT1.3, OsGS1;2, and OsGS2 was recorded in the roots of cv. Yangyujing 2 in comparison with cv. Nanjing 45, ultimately resulting in higher N content and dry weight in cv. Yangyujing 2. Stronger (3)H-IAA export from tiller stems was observed in cv. Yangyujing 2, mainly due to higher expression level of auxin efflux transporters. Moreover, tillers in auxin efflux transporter mutant ospin9 did not respond to NH4(+) supply relative to wild-type plants. These findings can be used in the molecular breeding of rice varieties to simultaneously improve rice population productivity and reduce N fertilizer input.
PMID: 34798463
J Plant Physiol , IF:3.549 , 2021 Nov , V266 : P153539 doi: 10.1016/j.jplph.2021.153539
Arabidopsis antiporter CHX23 and auxin transporter PIN8 coordinately regulate pollen growth.
MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.; Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau, School of Life Sciences, Qinghai Normal University, Xining, 810008, China.; MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China. Electronic address: qiuqsh@lzu.edu.cn.
Both the antiporter CHX23 (Cation/Proton Exchangers 23) and auxin transporter PIN8 (PIN-FORMED 8) are localized in the ER and regulate pollen growth in Arabidopsis. But how these two proteins regulate pollen growth remains to be studied. Here, we report that CHX23 and PIN8 act coordinately in regulating pollen growth. The chx23 mutant was reduced in pollen growth and normally shaped pollen grains, and complementation with CHX23 restored both pollen growth and normal pollen morphology. NAA treatments showed that CHX23 was crucial for pollen auxin homeostasis. The pin8 chx23 double mutant was decreased in pollen growth and normal pollen grains, indicating the joint effort of CHX23 and PIN8 in pollen growth. In vivo germination assay showed that CHX23 and PIN8 were involved in the early stage of pollen growth. CHX23 and PIN8 also function collaboratively in maintaining pollen auxin homeostasis. PIN8 depends on CHX23 in regulating pollen morphology and response to NAA treatments. CHX23 co-localized with PIN8, but there was no physical interaction. KCl and NaCl treatments showed that pollen growth of chx23 was reduced less than Col-0; pin8 chx23 was reduced less than chx23 and pin8. Together, CHX23 may regulate PIN8 function and hence pollen growth through controlling K(+) and Na(+) homeostasis mediated by its transport activity.
PMID: 34628190
J Microbiol , IF:3.422 , 2021 Nov doi: 10.1007/s12275-022-1474-8
Devosia rhizoryzae sp. nov., and Devosia oryziradicis sp. nov., novel plant growth promoting members of the genus Devosia, isolated from the rhizosphere of rice plants.
Department of Life Science, Dongguk University-Seoul, Goyang, 10326, Republic of Korea.; Department of Life Science, Dongguk University-Seoul, Goyang, 10326, Republic of Korea. tseo@dongguk.edu.
Two novel Gram-negative, aerobic, asporogenous, motile, rod-shaped, orange and white pigmented, designated as LEGU1(T) and G19(T), were isolated from the roots of rice plants, collected from Goyang, South Korea. Phylogenetic analysis based on their 16S rRNA gene sequences revealed that they belonged to the genus Devosia and formed a different lineage and clusters with different members of the genus Devosia. These strains shared common chemotaxonomic features. In particular, they had Q-10 as the sole quinone, phosphatidylglycerol, diphosphatidylglycerol as the principal polar lipids and C16:0, C18:1omega7c 11-methyl and summed feature 8 (comprising C18:1omega7c/C18:1omega6c) as the main fatty acids. The draft genome sequences of strains LEGU1(T) and G19(T) were 3,524,978 and 3,495,520 bp in size, respectively. Their average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were 72.8-81.9% and 18.7-25.1%, respectively, with each other and type strains of related species belonging to the genus Devosia, suggesting that these two strains represent novel species. The G + C content of strains LEGU1(T) and G19(T) were 62.1 and 63.8%, respectively. Of the two strains, only LEGU1(T) produced carotenoid and flexirubin-type pigment. Both strains produced siderophore and indole acetic acid (IAA) in the presence of L-tryptophan. Siderophore biosynthesis genes, auxin responsive genes and tryptophan biosynthesis genes were present in their genomes. The present study aimed to determine the detailed taxonomic positions of the strains using the modern polyphasic approach. Based on the results of polyphasic analysis, these strains are suggested to be two novel bacterial species within the genus Devosia. The proposed names are D. rhizoryzae sp. nov., and Devosia oryziradicis sp. nov., respectively. The plant growth promoting effects of these strains suggest that they can be exploited to improve rice crop productivity. The type strain of\} D. rhizoryzae is LEGU1(T) (KCTC 82712(T) = NBRC 114485(T)) and D. oryziradicis is G19(T) (KCTC 82688(T) = NBRC 114842(T)).
PMID: 34826099
Protoplasma , IF:3.356 , 2021 Nov doi: 10.1007/s00709-021-01724-z
Micrococcus luteus LS570 promotes root branching in Arabidopsis via decreasing apical dominance of the primary root and an enhanced auxin response.
Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacan, Mexico.; Catedratico CONACYT-Instituto de Ecologia A.C. Red de Estudios Moleculares Avanzados, Cluster BioMimic(R), Instituto de Ecologia A.C. Carretera Antigua a Coatepec, 351, El Haya, Xalapa, Veracruz, 91073, Mexico.; Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio B3, Ciudad Universitaria, C. P. 58030, Morelia, Michoacan, Mexico. jbucio@umich.mx.
The interaction of plant roots with bacteria is influenced by chemical signaling, where auxins play a critical role. Auxins exert positive or negative influences on the plant traits responsible of root architecture configuration such as root elongation and branching and root hair formation, but how bacteria that modify the plant auxin response promote or repress growth, as well as root structure, remains unknown. Here, we isolated and identified via molecular and electronic microscopy analysis a Micrococcus luteus LS570 strain as a plant growth promoter that halts primary root elongation in Arabidopsis seedlings and strongly triggers root branching and absorptive potential. The root biomass was exacerbated following root contact with bacterial streaks, and this correlated with inducible expression of auxin-related gene markers DR5:GUS and DR5:GFP. Cellular and structural analyses of root growth zones indicated that the bacterium inhibits both cell division and elongation within primary root tips, disrupting apical dominance, and as a consequence differentiation programs at the pericycle and epidermis, respectively, triggers the formation of longer and denser lateral roots and root hairs. Using Arabidopsis mutants defective on auxin signaling elements, our study uncovers a critical role of the auxin response factors ARF7 and ARF19, and canonical auxin receptors in mediating both the primary root and lateral root response to M. luteus LS570. Our report provides very basic information into how actinobacteria interact with plants and direct evidence that the bacterial genus Micrococcus influences the cellular and physiological plant programs ultimately responsible of biomass partitioning.
PMID: 34792622
PLoS One , IF:3.24 , 2021 , V16 (11) : Pe0259465 doi: 10.1371/journal.pone.0259465
The chitinolytic activity of the Curtobacterium sp. isolated from field-grown soybean and analysis of its genome sequence.
Department of Biochemistry and Molecular Biology, University of Belgrade - Faculty of Biology, Belgrade, Serbia.; Ras Al Khaimah Municipality Department, Director Environment Laboratories, Dubai, United Arab Emirates.; Embrapa Trigo, Passo Fundo, Rio Grande do Sul, Brazil.; Federal Research Centre for Cultivated Plants (JKI), Institute for Plant Protection in Horticulture and Forests, Julius Kuhn-Institut, Braunschweig, Germany.; Industrial Biotechnology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Buenos Aires, Argentina.
Curtobacterium sp. GD1 was isolated from leaves of conventionally grown soybean in Brazil. It was noteworthy that among all bacteria previously isolated from the same origin, only Curtobacterium sp. GD1 showed a strong chitinase activity. The enzyme was secreted and its production was induced by the presence of colloidal chitin in the medium. The chitinase was partially purified and characterized: molecular weight was approximately 37 kDa and specific activity 90.8 U/mg. Furthermore, Curtobacterium sp. GD1 genome was sequenced and analyzed. Our isolate formed a phylogenetic cluster with four other Curtobacterium spp. strains, with ANIb/ANIm >/= 98%, representing a new, still non described Curtobacterium species. The circular genome visualization and comparison of genome sequences of strains forming new cluster indicated that most regions within their genomes were highly conserved. The gene associated with chitinase production was identified and the distribution pattern of glycosyl hydrolases genes was assessed. Also, genes associated with catabolism of structural carbohydrates such as oligosaccharides, mixed polysaccharides, plant and animal polysaccharides, as well as genes or gene clusters associated with resistance to antibiotics, toxic compounds and auxin biosynthesis subsystem products were identified. The abundance of putative glycosyl hydrolases in the genome of Curtobacterium sp. GD1 suggests that it has the tools for the hydrolysis of different polysaccharides. Therefore, Curtobacterium sp. GD1 isolated from soybean might be a bioremediator, biocontrol agent, an elicitor of the plant defense responses or simply degrader.
PMID: 34731210
Plant Biol (Stuttg) , IF:3.081 , 2021 Nov , V23 (6) : P1118-1127 doi: 10.1111/plb.13299
Function analysis of a cotton R2R3 MYB transcription factor GhMYB3 in regulating plant trichome development.
Cotton Research Institute, Shanxi Agricultural University, Yuncheng, China.; National Key Laboratory of Plant Molecular genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China.; Nanjing Agricultural University, Nanjing, China.
Cotton is an important fibre-producing crop. Cotton fibres consist of highly elongated trichomes derived from the ovule. To improve the quality of cotton, it is necessary to identify the genes regulating fibre development. GhMYB3 was identified through bioinfomatic analysis and introduced to Arabidopsis and cotton to observe the phenotype. Protein inteaction and promoter bingding assays were conducted to explore the role of GhMYB3 in trichome fibre growth. Cotton fibre development might share a similar regulatory mechanism to Arabidopsis leaf trichomes, which is determined by the essential regulatory complex, MYB-bHLH-WD40. The GL1-like R2R3 MYB transcription factor GhMYB3 interacts with the AtGL3 protein involved in Arabidopsis trichome development. Ectopic expression of GhMYB3 could rescue the glabrous phenotype of the Arabidopsis gl1 mutant and produced more ectopic trichomes on inflorescence stems and floral organs, confirming its orthologous function in plant trichome development. The expression of GhMYB3 increased in response to exogenous gibberellin (GA3 ), auxin (IAA) and methyl jasmonate (MeJA). Overexpression of this gene in cotton leads to a slight increase in fibre length and lint percentage, possibly by activating the transcription of its downstream gene GhRDL1 or other fibre-related genes. The results increase our understanding of the key role of GhMYB3 in positively controlling plant trichome development, and this gene could be a potential target for molecular breeding in cotton.
PMID: 34396658
Plant Biol (Stuttg) , IF:3.081 , 2021 Nov , V23 (6) : P894-904 doi: 10.1111/plb.13303
Auxin and its role in plant development: structure, signalling, regulation and response mechanisms.
Programa de Pos-Graduacao em Bioquimica, Centro de Biociencias, Universidade Federal do Rio Grande do Norte, Natal, Brazil.; Laboratorio de Transformacao de Plantas e Analises em Microscopia, Departamento de Biologia Celular e Genetica, Universidade Federal do Rio Grande do Norte, Natal, Brazil.
Auxins are plant hormones that play a central role in controlling plant growth and development across different environmental conditions. Even at low concentrations, auxins can regulate gene expression through specific transcription factors and proteins that are modulated to environmental responses in the signalling cascade. Auxins are synthesized in tissues with high cell division activity and distributed by specific transmembrane proteins that regulate efflux and influx. This review presents recent advances in understanding the biosynthetic pathways, both dependent and independent of tryptophan, highlighting the intermediate indole compounds (indole-3-acetamide, indole-3-acetaldoxime, indole-3-pyruvic acid and tryptamine) and the key enzymes for auxin biosynthesis, such as YUCs and TAAs. In relation to the signalling cascade, it has been shown that auxins influence gene expression regulation by the connection between synthesis and distribution. Moreover, the molecular action of the auxin response factors and auxin/indole-3-acetic acid transcription factors with the F-box TIR1/AFB auxin receptors regulates gene expression. In addition, the importance of microRNAs in the auxin signalling pathway and their influence on plant plasticity to environmental fluctuations is also demonstrated. Finally, this review describes the chemical and biological processes involving auxins in plants.
PMID: 34396657
Plant Direct , IF:3.038 , 2021 Nov , V5 (11) : Pe361 doi: 10.1002/pld3.361
Electrophysiological study of Arabidopsis ABCB4 and PIN2 auxin transporters: Evidence of auxin activation and interaction enhancing auxin selectivity.
Department of Botany University of Wisconsin-Madison Madison WI USA.; Present address: Division of Science and Math University of Minnesota Morris MN USA.
Polar auxin transport through plant tissue strictly requires polarly localized PIN proteins and uniformly distributed ABCB proteins. A functional synergy between the two types of membrane protein where their localizations overlap may create the degree of asymmetric auxin efflux required to produce polar auxin transport. We investigated this possibility by expressing ABCB4 and PIN2 in human embryonic kidney cells and measuring whole-cell ionic currents with the patch-clamp technique and CsCl-based electrolytes. ABCB4 activity was 1.81-fold more selective for Cl(-) over Cs(+) and for PIN2 the value was 2.95. We imposed auxin gradients and determined that ABCB4 and PIN2 were 12-fold more permeable to the auxin anion (IAA(-)) than Cl(-). This measure of the intrinsic selectivity of the transport pathway was 21-fold when ABCB4 and PIN2 were co-expressed. If this increase occurs in plants, it could explain why asymmetric PIN localization is not sufficient to create polar auxin flow. Some form of co-action or synergy between ABCB4 and PIN2 that increases IAA(-) selectivity at the cell face where both occur may be important. We also found that auxin stimulated ABCB4 activity, which may contribute to a self-reinforcement of auxin transport known as canalization.
PMID: 34816076
PeerJ , IF:2.984 , 2021 , V9 : Pe12328 doi: 10.7717/peerj.12328
Transcriptome-based analysis of the hormone regulation mechanism of gender differentiation in Juglans mandshurica Maxim.
College of Forestry, Shenyang Agricultural University, Shenyang, China.; Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, Shenyang, China.
Juglans mandshurica Maxim is a hermaphroditic plant belonging to the genus Juglans in the family Juglandaceae. The pollination period of female flowers is different from the loose powder period of male flowers on the same tree. In several trees, female flowers bloom first, whereas in others, male flowers bloom first. In this study, male and female flower buds of J. mandshurica at the physiological differentiation stage were used. Illumina-based transcriptome sequencing was performed, and the quality of the sequencing results was evaluated and analyzed. A total of 138,138 unigenes with an average length of 788 bp were obtained. There were 8,116 differentially expressed genes (DEGs); 2,840 genes were upregulated, and 5,276 genes were downregulated. The DEGs were classified by Gene Ontology and analyzed by Kyoto Encyclopedia of Genes and Genomes. The signal transduction factors involved in phytohormone synthesis were selected. The results displayed that ARF and SAUR were expressed differently in the auxin signaling pathway. Additionally, DELLA protein (a negative regulator of gibberellin), the cytokinin synthesis pathway, and A-ARR were downregulated. On April 2nd, the contents of IAA, GA, CTK, ETH and SA in male and female flower buds of two types of J. mandshurica were opposite, and there were obvious genes regulating gender differentiation. Overall, we found that the sex differentiation of J. mandshurica was related to various hormone signal transduction pathways, and hormone signal transduction plays a leading role in regulation.
PMID: 34820167
Ecol Evol , IF:2.912 , 2021 Nov , V11 (22) : P15882-15895 doi: 10.1002/ece3.8258
Genome-wide transcriptome signatures of ant-farmed Squamellaria epiphytes reveal key functions in a unique symbiosis.
German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Leipzig Germany.; South Pacific Regional Herbarium Institute of Applied Sciences The University of the South Pacific Suva Fiji.; Royal Botanic Gardens Kew Richmond UK.; Systematic Botany and Mycology Department of Biology University of Munich (LMU) Munich Germany.; Department of Biology Washington University Saint Louis Missouri USA.; Ecology and Evolutionary Biology School of Biosciences University of Sheffield Sheffield UK.
Farming of fungi by ants, termites, or beetles has led to ecologically successful societies fueled by industrial-scale food production. Another type of obligate insect agriculture in Fiji involves the symbiosis between the ant Philidris nagasau and epiphytes in the genus Squamellaria (Rubiaceae) that the ants fertilize, defend, harvest, and depend on for nesting. All farmed Squamellaria form tubers (domatia) with preformed entrance holes and complex cavity networks occupied by P. nagasau. The inner surface of the domatia consists of smooth-surfaced walls where the ants nest and rear their brood, and warty-surfaced walls where they fertilize their crop by defecation. Here, we use RNA sequencing to identify gene expression patterns associated with the smooth versus warty wall types. Since wall differentiation occurred in the most recent common ancestor of all farmed species of Squamellaria, our study also identifies genetic pathways co-opted following the emergence of agriculture. Warty-surfaced walls show many upregulated genes linked to auxin transport, root development, and nitrogen transport consistent with their root-like function; their defense-related genes are also upregulated, probably to protect these permeable areas from pathogen entry. In smooth-surfaced walls, genes functioning in suberin and wax biosynthesis are upregulated, contributing to the formation of an impermeable ant-nesting area in the domatium. This study throws light on a number of functional characteristics of plant farming by ants and illustrates the power of genomic studies of symbiosis.
PMID: 34824797
Lett Appl Microbiol , IF:2.858 , 2021 Nov , V73 (5) : P658-671 doi: 10.1111/lam.13556
Elucidating key plant growth-promoting (PGPR) traits in Burkholderia sp. Nafp2/4-1b (=SARCC-3049) using gnotobiotic assays and whole-genome-sequence analysis.
Agricultural Research Council, Plant Health and Protection, Pretoria, Queenswood, South Africa.; School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa.; Agricultural Research Council, Biotechnology Platform, Onderstepoort, South Africa.; ARC-Biometry, Central Office, Pretoria, South Africa.
Burkholderia sp. Nafp2/4-1b (=SARCC-3049) is a plant growth-promoting rhizobacteria (PGPR) initially isolated from the rhizosphere of pristine grassland in South Africa, and its ability to enhance growth was previously evaluated on maize (Zea mays L.). Here, the bacterium was tested with the aim of investigating its role in improving the nodulation and growth of the forage legume lucerne (Medicago sativa L.) when it is co-inoculated with the rhizobial symbionts of this legume in the glasshouse. When the co-inoculation resulted in a statistically significant (P = 0.05) increase in the number of nodules and improved plant biomass compared with single inoculation, we sequenced and analysed its genome to gain a better understanding of the genetic determinants responsible for the observed PGPR traits. The Illumina HiSeq 2500-sequenced genome resulted in 92 scaffolds, with an N50 of 322 407 bp, a total draft genome size of 7 788 045 bp and GC content of 66.2%. Analysis of the genome sequence confirmed the presence of a number of essential genes that code for various PGPR traits. The main plant beneficial genes associated with PGPR traits in Burkholderia sp. Nafp2/4-1b include pyoverdine siderophores biosynthesis gene (PvdF); acdS that codes for 1-aminocyclopropane-1-carboxylate (ACC) deaminase; the tryptophan synthase genes involved in auxin biosynthesis (TSA1, TSB1) and the pqqABCDE operon related to phosphate solubilization. This study generated valuable information on the potential of the PGPR Burkholderia sp. strain Nafp2/4-1b as an effective commercial inoculant, which warrants further formulation and field application studies before developing it into a low cost, environmentally safe and effective biofertilizer.
PMID: 34426983
Mol Biol Rep , IF:2.316 , 2021 Nov , V48 (11) : P7293-7301 doi: 10.1007/s11033-021-06729-8
Comparison of the transcriptomic responses of two Chrysanthemum morifolium cultivars to low light.
Henan Provincial Key University Laboratory of Plant-Microbe Interactions, College of Biology and Food, Shangqiu Normal University, Shangqiu, 476000, China.; Henan Provincial Key University Laboratory of Plant-Microbe Interactions, College of Biology and Food, Shangqiu Normal University, Shangqiu, 476000, China. peidongli@126.com.
BACKGROUND: Low light is a primary regulator of chrysanthemum growth. Our aim was to analyse the different transcriptomic responses of two Chrysanthemum morifolium cultivars to low light. METHODS AND RESULTS: We conducted a transcriptomic analysis of leaf samples from the 'Nannonggongfen' and 'Nannongxuefeng' chrysanthemum cultivars following a 5-day exposure to optimal light (70%, control [CK]) or low-light (20%, LL) conditions. Gene Ontology (GO) classification of upregulated genes revealed these genes to be associated with 11 cellular components, 9 molecular functions, and 15 biological processes, with the majority being localized to the chloroplast, highlighting the role of chloroplast proteins as regulators of shading tolerance. Downregulated genes were associated with 11 cellular components, 8 molecular functions, and 16 biological processes. Heat map analyses suggested that basic helix-loop-helix domain genes and elongation factors were markedly downregulated in 'Nannongxuefeng' leaves, consistent with the maintenance of normal stem length, whereas no comparable changes were observed in 'Nanonggongfen' leaves. Subsequent qPCR analyses revealed that phytochrome-interacting factors and dormancy-associated genes were significantly upregulated under LL conditions relative to CK conditions, while succinate dehydrogenase 1, elongated hypocotyls 5, and auxin-responsive gene of were significantly downregulated under LL conditions. CONCLUSIONS: These findings suggest that LL plants were significantly lower than those of the CK plants. Low-light tolerant chrysanthemum cultivars may maintain reduced indole-3-acetic acid (IAA) and elongation factor expression as a means of preventing the onset of shade-avoidance symptoms.
PMID: 34689280
Biochem Genet , IF:1.89 , 2021 Nov doi: 10.1007/s10528-021-10158-4
Expression Analysis of AUX/IAA Family Genes in Apple Under Salt Stress.
Department of Pomology, College of Horticulture, China Agricultural University, Yuanmingyuan West Road No. 2, Haidian District, Beijing, 100193, People's Republic of China.; Department of Pomology, College of Horticulture, China Agricultural University, Yuanmingyuan West Road No. 2, Haidian District, Beijing, 100193, People's Republic of China. zhuyd@cau.edu.cn.
Members of the auxin/indoleacetic acid (Aux/IAA) gene family in plants are primary auxin-responsive genes that play important roles in many aspects of plant development and in responses to abiotic stress. Recently, 33 Aux/IAA have been identified in the apple genome. The biological responses of MdIAAs to salt stress are still unknown. In this study, Malus zumi, Malus baccata, and Malus x domestica 'Fuji' plantlets were subjected to salt stress by supplementing hydroponic media with NaCl at various concentrations. M. zumi showed the strongest salt resistance, followed by 'Fuji', and M. baccata was the most sensitive to salt stress. Tissue-specific expression profiles of MdIAAs were determined by quantitative real-time polymerase chain reaction. When apple plantlets were subjected to salt stress, most of salt-responsive MdIAAs were up-regulated by 1 h, 3 h, and 6 h in roots, shoot tips, and leaves, respectively. Highly expressed MdIAAs in roots, especially for M. zumi, consisted with the salt tolerance of apple rootstocks. Transgenic apple calli were tolerant to salt stress when over-expressed salt-responsive genes, MdIAA8, -9, and -25. These results provide clues about salt resistance in these three Malus species, which helps apple breeding of salt tolerance by genetic transformation.
PMID: 34802110
J Genet Eng Biotechnol , 2021 Nov , V19 (1) : P175 doi: 10.1186/s43141-021-00269-1
Picloram-induced enhanced callus-mediated regeneration, acclimatization, and genetic clonality assessment of gerbera.
Crop Research Unit (Genetics and Plant Breeding), Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, 741252, India. saikatgantait@yahoo.com.; Crop Research Unit (Genetics and Plant Breeding), Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia, West Bengal, 741252, India.
BACKGROUND: Gerbera jamesonii Bolus ex Hooker f. (African daisy) is listed among the top five most important ornamental plants in the global floricultural industry. To satisfy its demand, the floriculture industry relies on reproducible and effective propagation protocol while retaining the genetic uniformity of G. jamesonii. The present study, for the first time, reports the potential of picloram for enhanced induction of organogenic calli from leaves of G. jamesonii and its high-frequency indirect regeneration. RESULTS: The fastest induction of calli with maximum fresh and dry weight was recorded in the Murashige and Skoog (MS) semisolid medium supplemented with 1 mg/l picloram. In addition, callus induction was observed in 2,4-dichlorophenoxy acetic acid- and alpha-napthaleneaceticacid-supplemented media but with delayed response and reduced fresh and dry weight. The proliferated calli were transferred to shoot induction media containing MS salt and 0.5-1 mg/l N(6)-benzylaminopurine, kinetin, or thidiazuron. A mean number of ~6 shoots per callus were developed after 5 days of culture in the MS medium supplemented with 1 mg/l kinetin, with a mean length of 5.2 cm. Successful rooting of shoots was achieved in the MS medium fortified with 1.5 mg/l indole-3-acetic acid, wherein the earliest root initiation (~5 days), as well as the maximum number (~9) and length (~4.8 cm) of roots, were recorded. Complete plantlets were primarily acclimatized in sand before being transferred to a mixed substrate (of soil, sand, tea leaf waste, and cow urine) that secured >90% survival and further growth of the plantlets. Eventually, clonal fidelity of the in vitro regenerants assessed via inter-simple sequence repeats (ISSR) primers exhibited a monomorphic banding patterns that suggested genetic integrity within the plantlets as well as with their mother plant. CONCLUSIONS: The results of the present study should be of interest for commercial propagation and mutagenesis- as well as genetic transformation-related research.
PMID: 34779946