Mol Cell , IF:15.584 , 2019 Oct , V76 (1) : P177-190.e5 doi: 10.1016/j.molcel.2019.06.044
Nucleo-cytoplasmic Partitioning of ARF Proteins Controls Auxin Responses in Arabidopsis thaliana.
Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.; Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.; Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Engineering MechanoBiology, Washington University in St. Louis, St. Louis, MO 63130, USA.; Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, USA.; Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea.; Genome Technology Access Center, Department of Genetics, Washington University in St. Louis, St. Louis, MO 63110, USA.; Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Science and Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, MO 63130, USA.; Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Engineering MechanoBiology, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Science and Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, MO 63130, USA. Electronic address: strader@wustl.edu.
The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development. The auxin response factor (ARF) transcription factor family regulates auxin-responsive gene expression and exhibits nuclear localization in regions of high auxin responsiveness. Here we show that the ARF7 and ARF19 proteins accumulate in micron-sized assemblies within the cytoplasm of tissues with attenuated auxin responsiveness. We found that the intrinsically disordered middle region and the folded PB1 interaction domain of ARFs drive protein assembly formation. Mutation of a single lysine within the PB1 domain abrogates cytoplasmic assemblies, promotes ARF nuclear localization, and results in an altered transcriptome and morphological defects. Our data suggest a model in which ARF nucleo-cytoplasmic partitioning regulates auxin responsiveness, providing a mechanism for cellular competence for auxin signaling.
PMID: 31421981
Nat Commun , IF:12.121 , 2019 Oct , V10 (1) : P4865 doi: 10.1038/s41467-019-12845-8
Nuclear calcium signatures are associated with root development.
Department of Cell and Developmental Biology, John Innes Centre, Colney Lane, Norwich, NR4 7UH, UK.; Synthace Ltd, The Westworks, London, W12 7FQ, UK.; The Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK.; Department of Cell and Developmental Biology, John Innes Centre, Colney Lane, Norwich, NR4 7UH, UK. myriam.charpentier@jic.ac.uk.
In plants, nuclear Ca(2+) releases are essential to the establishment of nitrogen-fixing and phosphate-delivering arbuscular mycorrhizal endosymbioses. In the legume Medicago truncatula, these nuclear Ca(2+) signals are generated by a complex of nuclear membrane-localised ion channels including the DOES NOT MAKE INFECTIONS 1 (DMI1) and the cyclic nucleotide-gated channels (CNGC) 15s. DMI1 and CNCG15s are conserved among land plants, suggesting roles for nuclear Ca(2+) signalling that extend beyond symbioses. Here we show that nuclear Ca(2+) signalling initiates in the nucleus of Arabidopsis root cells and that these signals are correlated with primary root development, including meristem development and auxin homeostasis. In addition, we demonstrate that altering genetically AtDMI1 is sufficient to modulate the nuclear Ca(2+) signatures, and primary root development. This finding supports the postulate that stimulus-specific information can be encoded in the frequency and duration of a Ca(2+) signal and thereby regulate cellular function.
PMID: 31653864
Mol Biol Evol , IF:11.062 , 2019 Oct doi: 10.1093/molbev/msz230
Temporary Withdrawal Notice: Molecular evolution of auxin-mediated root initiation in plants.
PMID: 31584657
Genes Dev , IF:9.527 , 2019 Oct , V33 (19-20) : P1441-1455 doi: 10.1101/gad.328237.119
An improved auxin-inducible degron system preserves native protein levels and enables rapid and specific protein depletion.
Biochemistry and Molecular Genetics Department, University of Virginia, Charlottesville, Virginia 22908, USA.; Center for Public Health Genomics, University of Virginia, Charlottesville, Virginia 22908, USA.; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA.; Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269, USA.; Cancer Center, University of Virginia, Charlottesville, Virginia 22908, USA.
Rapid perturbation of protein function permits the ability to define primary molecular responses while avoiding downstream cumulative effects of protein dysregulation. The auxin-inducible degron (AID) system was developed as a tool to achieve rapid and inducible protein degradation in nonplant systems. However, tagging proteins at their endogenous loci results in chronic auxin-independent degradation by the proteasome. To correct this deficiency, we expressed the auxin response transcription factor (ARF) in an improved inducible degron system. ARF is absent from previously engineered AID systems but is a critical component of native auxin signaling. In plants, ARF directly interacts with AID in the absence of auxin, and we found that expression of the ARF PB1 (Phox and Bem1) domain suppresses constitutive degradation of AID-tagged proteins. Moreover, the rate of auxin-induced AID degradation is substantially faster in the ARF-AID system. To test the ARF-AID system in a quantitative and sensitive manner, we measured genome-wide changes in nascent transcription after rapidly depleting the ZNF143 transcription factor. Transcriptional profiling indicates that ZNF143 activates transcription in cis and regulates promoter-proximal paused RNA polymerase density. Rapidly inducible degradation systems that preserve the target protein's native expression levels and patterns will revolutionize the study of biological systems by enabling specific and temporally defined protein dysregulation.
PMID: 31467088
Proc Natl Acad Sci U S A , IF:9.412 , 2019 Oct , V116 (42) : P21285-21290 doi: 10.1073/pnas.1910916116
Noncanonical auxin signaling regulates cell division pattern during lateral root development.
Horticulture Biology and Metabolomics Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, China.; Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 201602 Shanghai, China.; University of Chinese Academy of Sciences, 100049 Beijing, China.; Horticulture Biology and Metabolomics Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, China; hejun@sibs.ac.cn tdxu@sibs.ac.cn.; Temasek Life Science Laboratory Ltd., National University of Singapore, 117604 Singapore.
In both plants and animals, multiple cellular processes must be orchestrated to ensure proper organogenesis. The cell division patterns control the shape of growing organs, yet how they are precisely determined and coordinated is poorly understood. In plants, the distribution of the phytohormone auxin is tightly linked to organogenesis, including lateral root (LR) development. Nevertheless, how auxin regulates cell division pattern during lateral root development remains elusive. Here, we report that auxin activates Mitogen-Activated Protein Kinase (MAPK) signaling via transmembrane kinases (TMKs) to control cell division pattern during lateral root development. Both TMK1/4 and MKK4/5-MPK3/6 pathways are required to properly orient cell divisions, which ultimately determine lateral root development in response to auxin. We show that TMKs directly and specifically interact with and phosphorylate MKK4/5, which is required for auxin to activate MKK4/5-MPK3/6 signaling. Our data suggest that TMK-mediated noncanonical auxin signaling is required to regulate cell division pattern and connect auxin signaling to MAPK signaling, which are both essential for plant development.
PMID: 31570617
Proc Natl Acad Sci U S A , IF:9.412 , 2019 Oct , V116 (41) : P20770-20775 doi: 10.1073/pnas.1907181116
Fine control of aerenchyma and lateral root development through AUX/IAA- and ARF-dependent auxin signaling.
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Aichi, Japan; atkyama@mail.ecc.u-tokyo.ac.jp nakazono@agr.nagoya-u.ac.jp.; Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, 332-0012 Saitama, Japan.; Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, 113-8657 Tokyo, Japan.; Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Aichi, Japan.; Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, 921-8836 Ishikawa, Japan.; International Center for Research and Education in Agriculture, Nagoya University, Nagoya, 464-8601 Aichi, Japan.; The UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, WA 6009, Australia.
Lateral roots (LRs) are derived from a parental root and contribute to water and nutrient uptake from the soil. Auxin/indole-3-acetic acid protein (AUX/IAA; IAA) and auxin response factor (ARF)-mediated signaling are essential for LR formation. Lysigenous aerenchyma, a gas space created by cortical cell death, aids internal oxygen transport within plants. Rice (Oryza sativa) forms lysigenous aerenchyma constitutively under aerobic conditions and increases its formation under oxygen-deficient conditions; however, the molecular mechanisms regulating constitutive aerenchyma (CA) formation remain unclear. LR number is reduced by the dominant-negative effect of a mutated AUX/IAA protein in the iaa13 mutant. We found that CA formation is also reduced in iaa13 We have identified ARF19 as an interactor of IAA13 and identified a lateral organ boundary domain (LBD)-containing protein (LBD1-8) as a target of ARF19. IAA13, ARF19, and LBD1-8 were highly expressed in the cortex and LR primordia, suggesting that these genes function in the initiation of CA and LR formation. Restoration of LBD1-8 expression recovered aerenchyma formation and partly recovered LR formation in the iaa13 background, in which LBD1-8 expression was reduced. An auxin transport inhibitor suppressed CA and LR formation, and a natural auxin stimulated CA formation in the presence of the auxin transport inhibitor. Our findings suggest that CA and LR formation are both regulated through AUX/IAA- and ARF-dependent auxin signaling. The initiation of CA formation lagged that of LR formation, which indicates that the formation of CA and LR are regulated differently by auxin signaling during root development in rice.
PMID: 31548376
New Phytol , IF:8.512 , 2019 Oct , V224 (2) : P543-546 doi: 10.1111/nph.16140
A new wrinkle in our understanding of the role played by auxin in root gravitropism.
Laboratory of Genetics, University of Wisconsin-Madison, 425 G Henry Mall, Madison, WI, 53706, USA.
PMID: 31545888
New Phytol , IF:8.512 , 2019 Oct , V224 (1) : P5-7 doi: 10.1111/nph.16023
Elevated CO2 -induced improvement of mycorrhization - which players lie in-between?
Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, D06120, Halle, Germany.
PMID: 31325386
New Phytol , IF:8.512 , 2019 Oct , V224 (2) : P775-788 doi: 10.1111/nph.16068
Minimal auxin sensing levels in vegetative moss stem cells revealed by a ratiometric reporter.
Department of Plant Biology, Swedish University of Agricultural Sciences, The Linnean Centre for Plant Biology in Uppsala, SE-750 07, Uppsala, Sweden.
Efforts to reveal ancestral functions of auxin, a key regulator of plant growth and development, and its importance for evolution have been hampered by a fragmented picture of auxin response domains in early-diverging land plants. We report the mapping of auxin sensing and responses during vegetative moss development using novel reporters. We established a moss-specific ratiometric reporter (PpR2D2) for Auxin Response Element- and AUXIN RESPONSE FACTOR-independent auxin sensing in Physcomitrella patens, and its readout during vegetative development was compared with new promoter-based GmGH3::GFPGUS and DR5revV2::GFPGUS auxin response reporters. The ratiometric reporter responds rapidly to auxin in a time-, dose- and TRANSPORT INHIBITOR RESISTANT1/AUXIN F-BOX-dependent manner and marks known, anticipated and novel auxin sensing domains. It reveals proximal auxin sensing maxima in filamentous tissues and sensing minima in all five vegetative gametophytic stem cell types as well as dividing cells. PpR2D2 readout is compliant with an ancestral function of auxin as a positive regulator of differentiation vs proliferation in stem cell regions. The PpR2D2 reporter is a sensitive tool for high-resolution mapping of auxin sensing, which can increase our knowledge of auxin function in early-diverging land plants substantially, thereby advancing our understanding of its importance for plant evolution.
PMID: 31318450
New Phytol , IF:8.512 , 2019 Oct , V224 (2) : P749-760 doi: 10.1111/nph.16065
Lateral root initiation requires the sequential induction of transcription factors LBD16 and PUCHI in Arabidopsis thaliana.
Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Kobe, 657-8501, Japan.; Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0192, Japan.; Department of Biological Sciences, Graduate School of Science, Osaka University, 13 Toyonaka, Osaka, 560-0043, Japan.; Faculty of Science and Engineering, Konan University, Kobe, 658-5801, Japan.; Graduate School of Science and Technology, Kobe University, 1-1 Rokkodai, Kobe, 657-8501, Japan.; Department of Bioregulation and Biointeraction, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, 183-8509, Japan.; Center for Sustainable Resource Science, Riken, Yokohama, Kanagawa, 230-0045, Japan.; Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai, Fuchu, 183-8509, Japan.
Lateral root (LR) formation in Arabidopsis thaliana is initiated by asymmetric division of founder cells, followed by coordinated cell proliferation and differentiation for patterning new primordia. The sequential developmental processes of LR formation are triggered by a localized auxin response. LATERAL ORGAN BOUNDARIES-DOMAIN 16 (LBD16), an auxin-inducible transcription factor, is one of the key regulators linking auxin response in LR founder cells to LR initiation. We identified key genes for LR formation that are activated by LBD16 in an auxin-dependent manner. LBD16 targets identified include the transcription factor gene PUCHI, which is required for LR primordium patterning. We demonstrate that LBD16 activity is required for the auxin-inducible expression of PUCHI. We show that PUCHI expression is initiated after the first round of asymmetric cell division of LR founder cells and that premature induction of PUCHI during the preinitiation phase disrupts LR primordium formation. Our results indicate that LR initiation requires the sequential induction of transcription factors LBD16 and PUCHI.
PMID: 31310684
New Phytol , IF:8.512 , 2019 Oct , V224 (1) : P258-273 doi: 10.1111/nph.16028
Phosphoethanolamine N-methyltransferase 1 contributes to maintenance of root apical meristem by affecting ROS and auxin-regulated cell differentiation in Arabidopsis.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China.; Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
The continuous growth of roots requires the balance between cell division and differentiation. Reactive oxygen species (ROS) and auxin are important regulators of root development by affecting cell division and differentiation. The mechanism controlling the coordination of cell division and differentiation is not well understood. Using a forward genetic screen, we isolated a mutant, defective primary root 2 (dpr2), defective in root apical meristem (RAM) maintenance. The DPR2 gene encodes phosphoethanolamine N-methyltransferase 1 (PEAMT1) that catalyzes phosphocholine biosynthesis in Arabidopsis. We characterized the primary root phenotypes of dpr2 using various marker lines, using histochemical and pharmacological analysis to probe early root development. Loss-of-function of DPR2/PEAMT1 resulted in RAM consumption by affecting root stem cell niche, division zone, elongation and differentiation zone (EDZ). PIN-FORMED (PIN) protein abundance, PIN2 polar distribution and general endocytosis were impaired in the root tip of dpr2. Excess hydrogen peroxide and auxin accumulate in the EDZ of dpr2, leading to RAM consumption by accelerating cell differentiation. Suppression of ROS over-accumulation or inhibition of auxin signalling partially prevent RAM differentiation in dpr2 after choline starvation. Taken together, we conclude that the EDZ of the root tip is most sensitive to choline shortage, leading to RAM consumption through an ROS-auxin regulation module.
PMID: 31246280
New Phytol , IF:8.512 , 2019 Oct , V224 (1) : P188-201 doi: 10.1111/nph.16019
Differential regulation of auxin and cytokinin during the secondary vascular tissue regeneration in Populus trees.
State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China.; Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, 00014, Finland.; Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Finland.; Natural Resources Institute Finland (Luke), Production Systems, Plant Genetics, Helsinki, 00790, Finland.; Department of Botany, Connecticut College, New London, CT, 06320, USA.; The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK.
Tissue regeneration upon wounding in plants highlights the developmental plasticity of plants. Previous studies have described the morphological and molecular changes of secondary vascular tissue (SVT) regeneration after large-scale bark girdling in trees. However, how phytohormones regulate SVT regeneration is still unknown. Here, we established a novel in vitro SVT regeneration system in the hybrid aspen (Populus tremula x Populus tremuloides) clone T89 to bypass the limitation of using field-grown trees. The effects of phytohormones on SVT regeneration were investigated by applying exogenous hormones and utilizing various transgenic trees. Vascular tissue-specific markers and hormonal response factors were also examined during SVT regeneration. Using this in vitro regeneration system, we demonstrated that auxin and cytokinin differentially regulate phloem and cambium regeneration. Whereas auxin is sufficient to induce regeneration of phloem prior to continuous cambium restoration, cytokinin only promotes the formation of new phloem, not cambium. The positive role of cytokinin on phloem regeneration was further confirmed in cytokinin overexpression trees. Analysis of a DR5 reporter transgenic line further suggested that cytokinin blocks the re-establishment of auxin gradients, which is required for the cambium formation. Investigation on the auxin and cytokinin signalling genes indicated these two hormones interact to regulate SVT regeneration. Taken together, the in vitro SVT regeneration system allows us to make use of various molecular and genetic tools to investigate SVT regeneration. Our results confirmed that complementary auxin and cytokinin domains are required for phloem and cambium reconstruction.
PMID: 31230359
New Phytol , IF:8.512 , 2019 Oct , V224 (2) : P761-774 doi: 10.1111/nph.15932
Auxin-mediated statolith production for root gravitropism.
Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, No. 620, West Chang'an Avenue, Chang'an District, Xi'an, 710119, China.; Institute of Science and Technology (IST) Austria, 3400, Klosterneuburg, Austria.; Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, No.100 Science Avenue, Zhengzhou, 450001, China.; Cotton Research Institute, Chinese Academy of Agricultural Sciences, No. 38 Yellow River Avenue, Anyang, 455000, China.
Root gravitropism is one of the most important processes allowing plant adaptation to the land environment. Auxin plays a central role in mediating root gravitropism, but how auxin contributes to gravitational perception and the subsequent response are still unclear. Here, we showed that the local auxin maximum/gradient within the root apex, which is generated by the PIN directional auxin transporters, regulates the expression of three key starch granule synthesis genes, SS4, PGM and ADG1, which in turn influence the accumulation of starch granules that serve as a statolith perceiving gravity. Moreover, using the cvxIAA-ccvTIR1 system, we also showed that TIR1-mediated auxin signaling is required for starch granule formation and gravitropic response within root tips. In addition, axr3 mutants showed reduced auxin-mediated starch granule accumulation and disruption of gravitropism within the root apex. Our results indicate that auxin-mediated statolith production relies on the TIR1/AFB-AXR3-mediated auxin signaling pathway. In summary, we propose a dual role for auxin in gravitropism: the regulation of both gravity perception and response.
PMID: 31111487
New Phytol , IF:8.512 , 2019 Oct , V224 (1) : P106-116 doi: 10.1111/nph.15917
A novel CO2 -responsive systemic signaling pathway controlling plant mycorrhizal symbiosis.
Department of Horticulture, Zhejiang University, Zijingang Campus, 866 Yuhangtang Road, Hangzhou, 310058,, China.; Key Laboratory of Horticultural Plants Growth and Development, Agricultural Ministry of China, Yuhangtang Road 866, Hangzhou, 310058,, China.; Analysis Center of Agrobiology and Environmental Science, Zhejiang University, Yuhangtang Road 866, Hangzhou, 310058, China.; Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds, LS2 9JT, UK.
Elevated atmospheric carbon dioxide (eCO2 ) concentrations promote symbiosis between roots and arbuscular mycorrhizal fungi (AMF), modifying plant nutrient acquisition and cycling of carbon, nitrogen and phosphate. However, the biological mechanisms by which plants transmit aerial eCO2 cues to roots, to alter the symbiotic associations remain unknown. We used a range of interdisciplinary approaches, including gene silencing, grafting, transmission electron microscopy, liquid chromatography tandem mass spectrometry (LC-MS/MS), biochemical methodologies and gene transcript analysis to explore the complexities of environmental signal transmission from the point of perception in the leaves at the apex to the roots. Here we show that eCO2 triggers apoplastic hydrogen peroxide (H2 O2 )-dependent auxin production in tomato shoots followed by systemic signaling that results in strigolactone biosynthesis in the roots. This redox-auxin-strigolactone systemic signaling cascade facilitates eCO2 -induced AMF symbiosis and phosphate utilization. Our results challenge the current paradigm of eCO2 effects on AMF and provide new insights into potential targets for manipulation of AMF symbiosis for high nutrient utilization under future climate change scenarios.
PMID: 31087385
Plant Physiol , IF:6.902 , 2019 Oct , V181 (2) : P480-498 doi: 10.1104/pp.19.00346
Phosphorylation-Mediated Dynamics of Nitrate Transceptor NRT1.1 Regulate Auxin Flux and Nitrate Signaling in Lateral Root Growth.
Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 10083, China.; College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 10083, China.; Institute of Cellular and Molecular Botany, University of Bonn, Bonn, D-53115, Germany.; Centre of the Region Hana for Biotechnological and Agricultural Research, Faculty of Science, Palacky University, Olomouc 78301, Czech Republic.; Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 10083, China shanxy@bjfu.edu.cn.
The dual-affinity nitrate transceptor NITRATE TRANSPORTER1.1 (NRT1.1) has two modes of transport and signaling, governed by Thr-101 (T101) phosphorylation. NRT1.1 regulates lateral root (LR) development by modulating nitrate-dependent basipetal auxin export and nitrate-mediated signal transduction. Here, using the Arabidopsis (Arabidopsis thaliana) NRT1.1(T101D) phosphomimetic and NRT1.1(T101A) nonphosphorylatable mutants, we found that the phosphorylation state of NRT1.1 plays a key role in NRT1.1 function during LR development. Single-particle tracking revealed that phosphorylation affected NRT1.1 spatiotemporal dynamics. The phosphomimetic NRT1.1(T101D) form showed fast lateral mobility and membrane partitioning that facilitated auxin flux under low-nitrate conditions. By contrast, nonphosphorylatable NRT1.1(T101A) showed low lateral mobility and oligomerized at the plasma membrane (PM), where it induced endocytosis via the clathrin-mediated endocytosis and microdomain-mediated endocytosis pathways under high-nitrate conditions. These behaviors promoted LR development by suppressing NRT1.1-controlled auxin transport on the PM and stimulating Ca(2+)-ARABIDOPSIS NITRATE REGULATED1 signaling from the endosome.
PMID: 31431511
Plant Physiol , IF:6.902 , 2019 Oct , V181 (2) : P630-644 doi: 10.1104/pp.19.00497
The Rice Actin-Binding Protein RMD Regulates Light-Dependent Shoot Gravitropism.
The University of Adelaide-Shanghai Jiao Tong University Joint Laboratory for Plant Science and Breeding, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240 China.; School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, South Australia 5064, Australia.; Systems Biology and Mathematical Modeling Group, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany.; Bioinformatics Group, Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam-Golm, Germany.; Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824.; School of Biosciences, University of Melbourne, Parkville Victoria 3010, Melbourne, Australia.; The University of Adelaide-Shanghai Jiao Tong University Joint Laboratory for Plant Science and Breeding, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240 China zhangdb@sjtu.edu.cn.
Light and gravity are two key determinants in orientating plant stems for proper growth and development. The organization and dynamics of the actin cytoskeleton are essential for cell biology and critically regulated by actin-binding proteins. However, the role of actin cytoskeleton in shoot negative gravitropism remains controversial. In this work, we report that the actin-binding protein Rice Morphology Determinant (RMD) promotes reorganization of the actin cytoskeleton in rice (Oryza sativa) shoots. The changes in actin organization are associated with the ability of the rice shoots to respond to negative gravitropism. Here, light-grown rmd mutant shoots exhibited agravitropic phenotypes. By contrast, etiolated rmd shoots displayed normal negative shoot gravitropism. Furthermore, we show that RMD maintains an actin configuration that promotes statolith mobility in gravisensing endodermal cells, and for proper auxin distribution in light-grown, but not dark-grown, shoots. RMD gene expression is diurnally controlled and directly repressed by the phytochrome-interacting factor-like protein OsPIL16. Consequently, overexpression of OsPIL16 led to gravisensing and actin patterning defects that phenocopied the rmd mutant. Our findings outline a mechanism that links light signaling and gravity perception for straight shoot growth in rice.
PMID: 31416828
Plant Physiol , IF:6.902 , 2019 Oct , V181 (2) : P458-470 doi: 10.1104/pp.19.00575
Role of Smoke Stimulatory and Inhibitory Biomolecules in Phytochrome-Regulated Seed Germination of Lactuca sativa.
Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Scottsville 3209, South Africa.; Laboratory of Growth Regulators, Czech Academy of Sciences, Institute of Experimental Botany, and Palacky University, Faculty of Science, CZ-78371 Olomouc, Czech Republic.; Department of Chemical Biology and Genetics, Centre of Region Hana for Biotechnological and Agricultural Research, Faculty of Science, Palacky University, Olomouc, Holice CZ-78371, Czech Republic.; Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Scottsville 3209, South Africa rcpgd@ukzn.ac.za.
The biologically active molecules karrikinolide (KAR1) and trimethylbutenolide (TMB) present in wildfire smoke play a key role in regulating seed germination of many plant species. To elucidate the physiological mechanism by which smoke-water (SW), KAR1, and TMB regulate seed germination in photosensitive 'Grand Rapids' lettuce (Lactuca sativa), we investigated levels of the dormancy-inducing hormone abscisic acid (ABA), three auxin catabolites, and cytokinins (26 isoprenoid and four aromatic) in response to these compounds. Activity of the hydrolytic enzymes alpha-amylase and lipase along with stored food reserves (lipids, carbohydrate, starch, and protein) were also assessed. The smoke compounds precisely regulated ABA and hydrolytic enzymes under all light conditions. ABA levels under red (R) light were not significantly different in seeds treated with TMB or water. However, TMB-treated seeds showed significantly inhibited germination (33%) compared with water controls (100%). KAR1 significantly enhanced total isoprenoid cytokinins under dark conditions in comparison with other treatments; however, there was no significant effect under R light. Enhanced levels of indole-3-aspartic acid (an indicator of high indole-3-acetic acid accumulation, which inhibits lettuce seed germination) and absence of trans-zeatin and trans-zeatin riboside (the most active cytokinins) in TMB-treated seeds might be responsible for reduced germination under R light. Our results demonstrate that SW and KAR1 significantly promote lettuce seed germination by reducing levels of ABA and enhancing the activity of hydrolytic enzymes, which aids in mobilizing stored reserves. However, TMB inhibits germination by enhancing ABA levels and reducing the activity of hydrolytic enzymes.
PMID: 31413205
Plant Physiol , IF:6.902 , 2019 Oct , V181 (2) : P683-700 doi: 10.1104/pp.19.00707
Male Sterility in Maize after Transient Heat Stress during the Tetrad Stage of Pollen Development.
University of Regensburg, Cell Biology and Plant Biochemistry, 93053 Regensburg, Germany.; University of Florida, Environmental Horticulture Department, Gainesville, Florida 32611-0670.; Plant Genome and Systems Biology, Helmholtz Center Munich, D-85764 Neuherberg, Germany.; Environmental Simulations, Helmholtz Center Munich, D-85764 Neuherberg, Germany.; Department of Ecogenomics and Systems Biology, Division of Molecular Systems Biology, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria.; Vienna Metabolomics Center (VIME), University of Vienna, 1090 Vienna, Austria.; University of Regensburg, Cell Biology and Plant Biochemistry, 93053 Regensburg, Germany thomas.dresselhaus@ur.de.
Shifts in the duration and intensity of ambient temperature impair plant development and reproduction, particularly male gametogenesis. Stress exposure causes meiotic defects or premature spore abortion in male reproductive organs, leading to male sterility. However, little is known about the mechanisms underlying stress and male sterility. To elucidate these mechanisms, we imposed a moderate transient heat stress on maize (Zea mays) plants at the tetrad stage of pollen development. After completion of pollen development at optimal conditions, stress responses were assessed in mature pollen. Transient heat stress resulted in reduced starch content, decreased enzymatic activity, and reduced pollen germination, resulting in sterility. A transcriptomic comparison pointed toward misregulation of starch, lipid, and energy biosynthesis-related genes. Metabolomic studies showed an increase of Suc and its monosaccharide components, as well as a reduction in pyruvate. Lipidomic analysis showed increased levels of unsaturated fatty acids and decreased levels of saturated fatty acids. In contrast, the majority of genes involved in developmental processes such as those required for auxin and unfolded protein responses, signaling, and cell wall biosynthesis remained unaltered. It is noteworthy that changes in the regulation of transcriptional and metabolic pathway genes, as well as heat stress proteins, remained altered even though pollen could recover during further development at optimal conditions. In conclusion, our findings demonstrate that a short moderate heat stress during the highly susceptible tetrad stage strongly affects basic metabolic pathways and thus generates germination-defective pollen, ultimately leading to severe yield losses in maize.
PMID: 31378720
Plant Physiol , IF:6.902 , 2019 Oct , V181 (2) : P595-608 doi: 10.1104/pp.19.00148
LBD29-Involved Auxin Signaling Represses NAC Master Regulators and Fiber Wall Biosynthesis.
Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269.; Department of Biological Sciences, University of North Texas, Denton, Texas 76203.; Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, Connecticut 06269 huanzhong.wang@uconn.edu.; Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut 06269.
NAM, ATAF1/2 and CUC2 (NAC) domain transcription factors function as master switches in regulating secondary cell wall (SCW) biosynthesis in Arabidopsis (Arabidopsis thaliana) stems. Despite the importance of these NACs in fiber development, the upstream signal is still elusive. Using a large-scale mutant screening, we identified a dominant activation-tagging mutant, fiberless-d (fls-d), showing defective SCW development in stem fibers, similar to that of the nac secondary wall thickening promoting factor1-1 (nst1-1)nst3-3 double mutant. Overexpression of LATERAL ORGAN BOUNDARIES DOMAIN29 (LBD29) is responsible for the fls-d mutant phenotypes. By contrast, loss-of-function of LBD29, either in the dominant repression transgenic lines or in the transfer-DNA (T-DNA) insertion mutant lbd29-1, enhanced SCW development in fibers. Genetic analysis and transgenic studies demonstrated LBD29 depends on master regulators in mediating SCW biosynthesis, specifically NAC SECONDARY WALL THICKENING PROMOTING FACTOR1 (NST1), NST2, and NST3. Increasing indole-3-acetic acid (IAA) levels, either in stem tissues above a N-1-naphthylphthalamic acid-treated region or in plants directly sprayed with IAA, inhibits fiber wall thickening. The inhibition effect of naphthylphthalamic acid treatment and exogenous IAA application depends on a known auxin signaling pathway involving AUXIN RESPONSE FACTOR7 (ARF7)/ARF19 and LBD29. These results demonstrate auxin is upstream of LBD29 in repressing NAC master regulators, and therefore shed new light on the regulation of SCW biosynthesis in Arabidopsis.
PMID: 31377726
Plant Physiol , IF:6.902 , 2019 Oct , V181 (2) : P645-655 doi: 10.1104/pp.19.00576
AUXIN RESPONSE FACTOR17 Directly Regulates MYB108 for Anther Dehiscence.
Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China.; Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China znyang@shnu.edu.cn.
The timely release of mature pollen following anther dehiscence is essential for reproduction in flowering plants. AUXIN RESPONSE FACTOR17 (ARF17) plays a crucial role in pollen wall pattern formation, tapetum development, and auxin signal transduction in anthers. Here, we showed that ARF17 is also involved in anther dehiscence. The Arabidopsis (Arabidopsis thaliana) arf17 mutant exhibits defective endothecium lignification, which leads to defects in anther dehiscence. The expression of MYB108, which encodes a transcription factor important for anther dehiscence, was dramatically down-regulated in the flower buds of arf17 Chromatin immunoprecipitation assays and electrophoretic mobility shift assays showed ARF17 directly binds to the MYB108 promoter. In an ARF17-GFP transgenic line, in which ARF17-GFP fully complements the arf17 phenotype, ARF17-GFP was observed in the endothecia at anther stage 11. The GUS signal driven by the MYB108 promoter was also detected in endothecia at late anther stages in transgenic plants expressing promoterMYB108::GUS Thus, the expression pattern of both ARF17 and MYB108 is consistent with the function of these genes in anther dehiscence. Furthermore, the expression of MYB108 driven by the ARF17 promoter successfully restored the defects in anther dehiscence of arf17 These results demonstrated that ARF17 regulates the expression of MYB108 for anther dehiscence. Together with its function in microcytes and tapeta, ARF17 likely coordinates the development of different sporophytic cell layers in anthers. The ARF17-MYB108 pathway involved in regulating anther dehiscence is also discussed.
PMID: 31345954
Plant Physiol , IF:6.902 , 2019 Oct , V181 (2) : P578-594 doi: 10.1104/pp.19.00144
The SMO1 Family of Sterol 4alpha-Methyl Oxidases Is Essential for Auxin- and Cytokinin-Regulated Embryogenesis.
Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, and Tianjin Key Laboratory of Protein Sciences, 300071 Tianjin, China.; School of Life Sciences, The Chinese University of Hong Kong, Shatin, 999077 Hong Kong, China.; Centre National de la Recherche Scientifique, University of Bordeaux, Laboratoire de Biogenese Membranaire, Unite Mixte de Recherche 5200, 33140 Villenave d'Ornon, France.; Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, and Tianjin Key Laboratory of Protein Sciences, 300071 Tianjin, China shuzhenmen@nankai.edu.cn.
In the plant sterol biosynthetic pathway, sterol 4alpha-methyl oxidase1 (SMO1) and SMO2 enzymes are involved in the removal of the first and second methyl groups at the C-4 position, respectively. SMO2s have been found to be essential for embryonic and postembryonic development, but the roles of SMO1s remain unclear. Here, we found that the three Arabidopsis (Arabidopsis thaliana) SMO1 genes displayed different expression patterns. Single smo1 mutants and smo1-1 smo1-3 double mutants showed no obvious phenotype, but the smo1-1 smo1-2 double mutant was embryo lethal. The smo1-1 smo1-2 embryos exhibited severe defects, including no cotyledon or shoot apical meristem formation, abnormal division of suspensor cells, and twin embryos. These defects were associated with enhanced and ectopic expression of auxin biosynthesis and response reporters. Consistently, the expression pattern and polar localization of PIN FORMED1, PIN FORMED7, and AUXIN RESISTANT1 auxin transporters were dramatically altered in smo1-1 smo1-2 embryos. Moreover, cytokinin biosynthesis and response were reduced in smo1-1 smo1-2 embryos. Tissue culture experiments further demonstrated that homeostasis between auxin and cytokinin was altered in smo1-1 smo1-2 heterozygous mutants. This disturbed balance of auxin and cytokinin in smo1-1 smo1-2 embryos was accompanied by unrestricted expression of the quiescent center marker WUSCHEL-RELATED HOMEOBOX5 Accordingly, exogenous application of either auxin biosynthesis inhibitor or cytokinin partially rescued the embryo lethality of smo1-1 smo1-2 Sterol analyses revealed that 4,4-dimethylsterols dramatically accumulated in smo1-1 smo1-2 heterozygous mutants. Together, these data demonstrate that SMO1s function through maintaining correct sterol composition to balance auxin and cytokinin activities during embryogenesis.
PMID: 31341004
Sci Total Environ , IF:6.551 , 2019 Oct , V688 : P935-943 doi: 10.1016/j.scitotenv.2019.06.384
Regulation of endogenous phytohormones alters the fluoranthene content in Arabidopsis thaliana.
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210014, People's Republic of China.; College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.; College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210014, People's Republic of China. Electronic address: xuli602@njau.edu.cn.
Phytohormones are crucial endogenous modulators that regulate and integrate plant growth and responses to various environmental pollutants, including the uptake of pollutants into the plant. However, possible links between endogenous phytohormone pathways and pollutant accumulation are unclear. Here we describe the fluoranthene uptake, plant growth, and superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione S-transferase (GST) activities in relation to different endogenous phytohormones and different levels in Arabidopsis thaliana. Three phytohormone inhibitors-N-1-naphthyl-phthalamic acid (NPA), daminozide (DZ), and silver nitrate (SN)-were used to regulate endogenous auxin, gibberellin, and ethylene levels, respectively. Fluoranthene inhibited plant growth and root proliferation while increasing GST and SOD activity. The three inhibitors reduced fluoranthene levels in Arabidopsis by either affecting plant growth or modulating antioxidant enzyme activity. NPA reduced plant growth and increased CAT activity. SN promoted plant growth and increased POD and CAT activity, whereas DZ increased POD activity.
PMID: 31726575
J Exp Bot , IF:5.908 , 2019 Oct , V70 (20) : P5673-5686 doi: 10.1093/jxb/erz325
Autopolyploidization in switchgrass alters phenotype and flowering time via epigenetic and transcription regulation.
Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, China.; School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA.; Department of Life Sciences, University of Milan, Milan, Italy.; College of Grassland Science, Nanjing Agricultural University, Nanjing, China.; Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.
Polyploidization is a significant source of genomic and organism diversification during plant evolution, and leads to substantial alterations in plant phenotypes and natural fitness. To help understand the phenotypic and molecular impacts of autopolyploidization, we conducted epigenetic and full-transcriptomic analyses of a synthesized autopolyploid accession of switchgrass (Panicum virgatum) in order to interpret the molecular and phenotypic changes. We found that mCHH levels were decreased in both genic and transposable element (TE) regions, and that TE methylation near genes was decreased as well. Among 142 differentially expressed genes involved in cell division, cellulose biosynthesis, auxin response, growth, and reproduction processes, 75 of them were modified by 122 differentially methylated regions, 10 miRNAs, and 15 siRNAs. In addition, up-regulated PvTOE1 and suppressed PvFT probably contribute to later flowering time of the autopolyploid. The expression changes were probably associated with modification of nearby methylation sites and siRNAs. We also experimentally demonstrated that expression levels of PvFT and PvTOE1 were regulated by DNA methylation, supporting the link between alterations in methylation induced by polyploidization and the phenotypic changes that were observed. Collectively, our results show epigenetic modifications in synthetic autopolyploid switchgrass for the first time, and support the hypothesis that polyploidization-induced methylation is an important cause of phenotypic alterations and is potentially important for plant evolution and improved fitness.
PMID: 31419288
J Exp Bot , IF:5.908 , 2019 Oct , V70 (20) : P5715-5730 doi: 10.1093/jxb/erz354
PINOID is required for lateral organ morphogenesis and ovule development in cucumber.
College of Horticulture and Landscape Architecture, Hunan Agricultural University, Changsha, China.; Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, MOE Joint International Research Laboratory of Crop Molecular Breeding, China Agricultural University, Beijing, China.; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Northeast Region), Ministry of Agriculture, Northeast Agricultural University, Harbin, China.; Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China.; College of Horticulture, and FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China.; Beijing Vegetable Research Center, Beijing Academy of Agricultural and Forestry Sciences, Beijing Key Laboratory of Vegetable Germplasms Improvement, National Engineering Research Center for Vegetables, Beijing, China.; College of Horticulture, Northwest A&F University, Yangling, Shanxi, China.
Lateral organ development is essential for cucumber production. The protein kinase PINOID (PID) participates in distinct aspects of plant development by mediating polar auxin transport in different species. Here, we obtained a round leaf (rl) mutant that displayed extensive phenotypes including round leaf shape, inhibited tendril outgrowth, abnormal floral organs, and disrupted ovule genesis. MutMap+ analysis revealed that rl encodes a cucumber ortholog of PID (CsPID). A non-synonymous single nucleotide polymorphism in the second exon of CsPID resulted in an amino acid substitution from arginine to lysine in the rl mutant. Allelic testing using the mutant allele C356 with similar phenotypes verified that CsPID was the causal gene. CsPID was preferentially expressed in young leaf and flower buds and down-regulated in the rl mutant. Subcellular localization showed that the mutant form, Cspid, showed a dotted pattern of localization, in contrast to the continuous pattern of CsPID in the periphery of the cell and nucleus. Complementation analysis in Arabidopsis showed that CsPID, but not Cspid, can partially rescue the pid-14 mutant phenotype. Moreover, indole-3-acetic acid content was greatly reduced in the rl mutant. Transcriptome profiling revealed that transcription factors, ovule morphogenesis, and auxin transport-related genes were significantly down-regulated in the rl mutant. Biochemical analysis showed that CsPID physically interacted with a key polarity protein, CsREV (REVOLUTA). We developed a model in which CsPID regulates lateral organ morphogenesis and ovule development by stimulating genes related to auxin transport and ovule development.
PMID: 31407012
J Exp Bot , IF:5.908 , 2019 Oct , V70 (20) : P5731-5744 doi: 10.1093/jxb/erz342
Alq mutation increases fruit set rate and allows the maintenance of fruit yield under moderate saline conditions.
Instituto de Biologia Molecular y Celular de Plantas (UPV-CSIC), Universitat Politecnica de Valencia. Valencia, Spain.; Centro de Investigacion en Biotecnologia Agroalimentaria (BITAL), Universidad de Almeria, Almeria, Spain.
Arlequin (Alq) is a gain-of-function mutant whose most relevant feature is that sepals are able to become fruit-like organs due to the ectopic expression of the ALQ-TAGL1 gene. The role of this gene in tomato fruit ripening was previously demonstrated. To discover new functional roles for ALQ-TAGL1, and most particularly its involvement in the fruit set process, a detailed characterization of Alq yield-related traits was performed. Under standard conditions, the Alq mutant showed a much higher fruit set rate than the wild type. A significant percentage of Alq fruits were seedless. The results showed that pollination-independent fruit set in Alq is due to early transition from flower to fruit. Analysis of endogenous hormones in Alq suggests that increased content of cytokinins and decreased level of abscisic acid may account for precocious fruit set. Comparative expression analysis showed relevant changes of several genes involved in cell division, gibberellin metabolism, and the auxin signalling pathway. Since pollination-independent fruit set may be a very useful strategy for maintaining fruit production under adverse conditions, fruit set and yield in Alq plants under moderate salinity were assessed. Interestingly, Alq mutant plants showed a high yield under saline conditions, similar to that of Alq and the wild type under unstressed conditions.
PMID: 31328220
J Exp Bot , IF:5.908 , 2019 Oct , V70 (19) : P5041-5049 doi: 10.1093/jxb/erz283
Auxin biosynthesis: spatial regulation and adaptation to stress.
Department of Horticulture and Crop Science, The Ohio State University, Wooster, OH, USA.; Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK.
The plant hormone auxin is essential for plant growth and development, controlling both organ development and overall plant architecture. Auxin homeostasis is regulated by coordination of biosynthesis, transport, conjugation, sequestration/storage, and catabolism to optimize concentration-dependent growth responses and adaptive responses to temperature, water stress, herbivory, and pathogens. At present, the best defined pathway of auxin biosynthesis is the TAA/YUC route, in which the tryptophan aminotransferases TAA and TAR and YUCCA flavin-dependent monooxygenases produce the auxin indole-3-acetic acid from tryptophan. This review highlights recent advances in our knowledge of TAA/YUC-dependent auxin biosynthesis focusing on membrane localization of auxin biosynthetic enzymes, differential regulation in root and shoot tissue, and auxin biosynthesis during abiotic stress.
PMID: 31198972
Development , IF:5.611 , 2019 Oct , V146 (20) doi: 10.1242/dev.177527
Wheat AGAMOUS LIKE 6 transcription factors function in stamen development by regulating the expression of Ta APETALA3.
State Key Laboratory of Crop Stress Biology for Arid Areas and College of Agronomy, Northwest A&F University, Yangling 712100, China.; Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.; School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.; State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China lhf@nwsuaf.edu.cn kangzs@nwsuaf.edu.cn.; State Key Laboratory of Crop Stress Biology for Arid Areas and College of Agronomy, Northwest A&F University, Yangling 712100, China lhf@nwsuaf.edu.cn kangzs@nwsuaf.edu.cn.
Previous studies have revealed the functions of rice and maize AGAMOUS LIKE 6 (AGL6) genes OsMADS6 and ZAG3, respectively, in floral development; however, the functions of three wheat (Triticum aestivum) AGL6 genes are still unclear. Here, we report the main functions of wheat AGL6 homoeologous genes in stamen development. In RNAi plants, stamens showed abnormality in number and morphology, and a tendency to transform into carpels. Consistently, the expression of the B-class gene TaAPETALA3 (AP3) and the auxin-responsive gene TaMGH3 was downregulated, whereas the wheat ortholog of the rice carpel identity gene DROOPING LEAF was ectopically expressed in RNAi stamens. TaAGL6 proteins bind to the promoter of TaAP3 directly. Yeast one-hybrid and transient expression assays further showed that TaAGL6 positively regulates the expression of TaAP3 in vivo. Wheat AGL6 transcription factors interact with TaAP3, TaAGAMOUS and TaMADS13. Our findings indicate that TaAGL6 transcription factors play an essential role in stamen development through transcriptional regulation of TaAP3 and other related genes. We propose a model to illustrate the function and probable mechanism of this regulation. This study extends our understanding of AGL6 genes.
PMID: 31540915
PLoS Genet , IF:5.174 , 2019 Oct , V15 (10) : Pe1008465 doi: 10.1371/journal.pgen.1008465
Nitrate-responsive OBP4-XTH9 regulatory module controls lateral root development in Arabidopsis thaliana.
Laboratory of Photosynthesis and Environment, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
Plant root system architecture in response to nitrate availability represents a notable example to study developmental plasticity, but the underlying mechanism remains largely unknown. Xyloglucan endotransglucosylases (XTHs) play a critical role in cell wall biosynthesis. Here we assessed the gene expression of XTH1-11 belonging to group I of XTHs in lateral root (LR) primordia and found that XTH9 was highly expressed. Correspondingly, an xth9 mutant displayed less LR, while overexpressing XTH9 presented more LR, suggesting the potential function of XTH9 in controlling LR development. XTH9 gene mutation obviously alters the properties of the cell wall. Furthermore, nitrogen signals stimulated the expression of XTH9 to promote LRs. Genetic analysis revealed that the function of XTH9 was dependent on auxin-mediated ARF7/19 and downstream AFB3 in response to nitrogen signals. In addition, we identified another transcription factor, OBP4, that was also induced by nitrogen treatment, but the induction was much slower than that of XTH9. In contrast to XTH9, overexpressing OBP4 caused fewer LRs while OBP4 knockdown with OBP4-RNAi or an artificial miRNA silenced amiOBP4 line produced more LR. We further found OBP4 bound to the promoter of XTH9 to suppress XTH9 expression. In agreement with this, both OBP4-RNAi and crossed OBP4-RNAi & 35S::XTH9 lines led to more LR, but OBP4-RNAi & xth9 produced less LR, similar to xth9. Based on these findings we propose a novel mechanism by which OBP4 antagonistically controls XTH9 expression and the OBP4-XTH9 module elaborately sustains LR development in response to nitrate treatment.
PMID: 31626627
J Integr Plant Biol , IF:4.885 , 2019 Oct doi: 10.1111/jipb.12880
ZEITLUPE is required for shade avoidance in the wild tobacco Nicotiana attenuata.
Department of Molecular Ecology, Max-Planck-Institute for Chemical Ecology, Jena, 07745, Germany.; Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.
Being shaded is a common environmental stress for plants, especially for densely planted crops. Shade decreases red: far-red (R:FR) ratios that inactivate phytochrome B (PHYB) and subsequently release phytochrome interaction factors (PIFs). Shaded plants display elongated hypocotyls, internodes, and petioles, hyponastic leaves, early flowering and are inhibited in branching: traits collectively called the shade avoidance syndrome (SAS). ZEITLUPE (ZTL) is a circadian clock component and blue light photoreceptor, which is also involved in floral rhythms and plant defense in Nicotiana attenuata. ztl mutants are hypersensitive to red light and ZTL physically interacts with PHYB, suggesting the involvement of ZTL in R:FR light signaling. Here, we show that N. attenuata ZTL-silenced plants display a phenotype opposite to that of the SAS under normal light. After simulated shade, the normally induced transcript levels of the SAS marker gene, ATHB2 are attenuated in ZTL-silenced plants. The auxin signaling pathway, known to be involved in SAS, was also significantly attenuated. Furthermore, NaZTL directly interacts with NaPHYBs, and regulates the transcript levels of PHYBs, PIF3a, PIF7 and PIF8 under shade. Our results suggest that ZTL may regulate PHYB- and the auxin-mediated signaling pathway, which functions in the SAS of N. attenuata.
PMID: 31628717
Int J Mol Sci , IF:4.556 , 2019 Oct , V20 (21) doi: 10.3390/ijms20215311
Comparative Genome-wide Analysis and Expression Profiling of Histone Acetyltransferase (HAT) Gene Family in Response to Hormonal Applications, Metal and Abiotic Stresses in Cotton.
School of Life Sciences, Tsinghua University, Beijing 100084, China.; State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.; Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad campus, Abbottabad 22060, Pakistan.; Institute of Soil & Environmental Sciences, University of Agriculture, Faisalabad 38000, Pakistan.; Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON N6A5B8 Canada.; Department of Plant breeding and Genetics, Ghazi University, Dera Ghazi Khan 32200, Pakistan.; Forage & Range Research, United States Department of Agriculture, Agricultural Research Service, Logan, UT 84322, USA.
Post-translational modifications are involved in regulating diverse developmental processes. Histone acetyltransferases (HATs) play vital roles in the regulation of chromation structure and activate the gene transcription implicated in various cellular processes. However, HATs in cotton, as well as their regulation in response to developmental and environmental cues, remain unidentified. In this study, 9 HATs were identified from Gossypium raimondi and Gossypium arboretum, while 18 HATs were identified from Gossypium hirsutum. Based on their amino acid sequences, Gossypium HATs were divided into three groups: CPB, GNAT, and TAFII250. Almost all the HATs within each subgroup share similar gene structure and conserved motifs. Gossypium HATs are unevenly distributed on the chromosomes, and duplication analysis suggests that Gossypium HATs are under strong purifying selection. Gene expression analysis showed that Gossypium HATs were differentially expressed in various vegetative tissues and at different stages of fiber development. Furthermore, all the HATs were differentially regulated in response to various stresses (salt, drought, cold, heavy metal and DNA damage) and hormones (abscisic acid (ABA) and auxin (NAA)). Finally, co-localization of HAT genes with reported quantitative trait loci (QTL) of fiber development were reported. Altogether, these results highlight the functional diversification of HATs in cotton growth and fiber development, as well as in response to different environmental cues. This study enhances our understanding of function of histone acetylation in cotton growth, fiber development, and stress adaptation, which will eventually lead to the long-term improvement of stress tolerance and fiber quality in cotton.
PMID: 31731441
Int J Mol Sci , IF:4.556 , 2019 Oct , V20 (21) doi: 10.3390/ijms20215334
Development of an Efficient Protocol to Obtain Transgenic Coffee, Coffea arabica L., Expressing the Cry10Aa Toxin of Bacillus thuringiensis.
Departamanto de Biotecnologia y Bioquimica, Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Irapuato, Irapuato 36824, Mexico.; Departamento de Ingenieria Genetica, Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Irapuato, Irapuato 36824, Mexico.
This report presents an efficient protocol of the stable genetic transformation of coffee plants expressing the Cry10Aa protein of Bacillus thuringiensis. Embryogenic cell lines with a high potential of propagation, somatic embryo maturation, and germination were used. Gene expression analysis of cytokinin signaling, homedomains, auxin responsive factor, and the master regulators of somatic embryogenesis genes involved in somatic embryo maturation were evaluated. Plasmid pMDC85 containing the cry10Aa gene was introduced into a Typica cultivar of C. arabica L. by biobalistic transformation. Transformation efficiency of 16.7% was achieved, according to the number of embryogenic aggregates and transgenic lines developed. Stable transformation was proven by hygromycin-resistant embryogenic lines, green fluorescent protein (GFP) expression, quantitative analyses of Cry10Aa by mass spectrometry, Western blot, ELISA, and Southern blot analyses. Cry10Aa showed variable expression levels in somatic embryos and the leaf tissue of transgenic plants, ranging from 76% to 90% of coverage of the protein by mass spectrometry and from 3.25 to 13.88 mug/g fresh tissue, with ELISA. qPCR-based 2(-DeltaDeltaCt) trials revealed high transcription levels of cry10Aa in somatic embryos and leaf tissue. This is the first report about the stable transformation and expression of the Cry10Aa protein in coffee plants with the potential for controlling the coffee berry borer.
PMID: 31717779
Int J Mol Sci , IF:4.556 , 2019 Oct , V20 (21) doi: 10.3390/ijms20215357
Genome-Wide Analysis of Cotton miRNAs During Whitefly Infestation Offers New Insights into Plant-Herbivore Interaction.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China. lijy90@126.com.; USDA-ARS, Arid Land Agricultural Research Center, 21881 North Cardon Lane, Maricopa, AZ 85138, USA. joe.hull@ars.usda.gov.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China. sijialiang@webmail.hzau.edu.cn.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China. wangqq0515@163.com.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China. chenluo@webmail.hzau.edu.cn.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China. qhzhang@outlook.com.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China. mjwang@mail.hzau.edu.cn.; National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad 38000, Pakistan. shahidmansoor7@gmail.com.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China. xlzhang@mail.hzau.edu.cn.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China. jsx@mail.hzau.edu.cn.
Although the regulatory function of miRNAs and their targets have been characterized in model plants, a possible underlying role in the cotton response to herbivore infestation has not been determined. To investigate this, we performed small RNA and degradome sequencing between resistant and susceptible cotton cultivar following infestation with the generalist herbivore whitefly. In total, the 260 miRNA families and 241 targets were identified. Quantitative-PCR analysis revealed that several miRNAs and their corresponding targets exhibited dynamic spatio-temporal expression patterns. Moreover, 17 miRNA precursors were generated from 29 long intergenic non-coding RNA (lincRNA) transcripts. The genome-wide analysis also led to the identification of 85 phased small interfering RNA (phasiRNA) loci. Among these, nine PHAS genes were triggered by miR167, miR390, miR482a, and two novel miRNAs, including those encoding a leucine-rich repeat (LRR) disease resistance protein, an auxin response factor (ARF) and MYB transcription factors. Through combined modeling and experimental data, we explored and expanded the miR390-tasiARF cascade during the cotton response to whitefly. Virus-induced gene silencing (VIGS) of ARF8 from miR390 target in whitefly-resistant cotton plants increased auxin and jasmonic acid (JA) accumulation, resulting in increased tolerance to whitefly infestation. These results highlight the provides a useful transcriptomic resource for plant-herbivore interaction.
PMID: 31661835
Int J Mol Sci , IF:4.556 , 2019 Oct , V20 (20) doi: 10.3390/ijms20205221
The miR396-GRF Regulatory Module Controls the Embryogenic Response in Arabidopsis via an Auxin-Related Pathway.
Department of Genetics, University of Silesia, Faculty of Biology and Environmental Protection, 40-032 Katowice, Poland. aleksandra.sommer@gmail.com.; Department of Genetics, University of Silesia, Faculty of Biology and Environmental Protection, 40-032 Katowice, Poland. malgorzata.gaj@us.edu.pl.
In plants, microRNAs have been indicated to control various developmental processes, including somatic embryogenesis (SE), which is triggered in the in vitro cultured somatic cells of plants. Although a transcriptomic analysis has indicated that numerous MIRNAs are differentially expressed in the SE of different plants, the role of specific miRNAs in the embryogenic reprogramming of the somatic cell transcriptome is still poorly understood. In this study, we focused on performing a functional analysis of miR396 in SE given that the transcripts of MIR396 genes and the mature molecules of miR396 were found to be increased during an SE culture of Arabidopsis [1]. In terms of miR396 in embryogenic induction, we observed the SE-associated expression pattern of MIR396b in explants of the beta-glucuronidase (GUS) reporter line. In order to gain insight into the miR396-controlled mechanism that is involved in SE induction, the embryogenic response of mir396 mutants and the 35S:MIR396b overexpressor line to media with different 2,4-Dichlorophenoxyacetic acid (2,4-D) concentrations was evaluated. The results suggested that miR396 might contribute to SE induction by controlling the sensitivity of tissues to auxin treatment. Within the targets of miR396 that are associated with SE induction, we identified genes encoding the GROWTH-REGULATING FACTOR (GRF) transcription factors, including GRF1, GRF4, GRF7, GRF8, and GRF9. Moreover, the study suggested a regulatory relationship between miR396, GRF, and the PLETHORA (PLT1 and PLT2) genes during SE induction. A complex regulatory relationship within the miR396-GRF1/4/8/9-PLT1/2 module that involves the negative and positive control of GRFs and PLT (respectively) by miR396 might be assumed.
PMID: 31640280
Int J Mol Sci , IF:4.556 , 2019 Oct , V20 (20) doi: 10.3390/ijms20205144
Overexpression of OsPIN2 Regulates Root Growth and Formation in Response to Phosphate Deficiency in Rice.
National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China. sunhuwei19431@163.com.; National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China. guojingli188@126.com.; National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China. fugui_xu5683@126.com.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China. 2019203041@njau.edu.cn.; Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. 2019203041@njau.edu.cn.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China. 2017103139@njau.edu.cn.; Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. 2017103139@njau.edu.cn.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China. 2018103147@njau.edu.cn.; Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. 2018103147@njau.edu.cn.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China. 2018103148@njau.edu.cn.; Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. 2018103148@njau.edu.cn.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China. ghxu@njau.edu.cn.; Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. ghxu@njau.edu.cn.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China. ylzhang@njau.edu.cn.; Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. ylzhang@njau.edu.cn.
The response of root architecture to phosphate (P) deficiency is critical in plant growth and development. Auxin is a key regulator of plant root growth in response to P deficiency, but the underlying mechanisms are unclear. In this study, phenotypic and genetic analyses were undertaken to explore the role of OsPIN2, an auxin efflux transporter, in regulating the growth and development of rice roots under normal nutrition condition (control) and low-phosphate condition (LP). Higher expression of OsPIN2 was observed in rice plants under LP compared to the control. Meanwhile, the auxin levels of roots were increased under LP relative to control condition in wild-type (WT) plants. Compared to WT plants, two overexpression (OE) lines had higher auxin levels in the roots under control and LP. LP led to increased seminal roots (SRs) length and the root hairs (RHs) density, but decreased lateral roots (LRs) density in WT plants. However, overexpression of OsPIN2 caused a loss of sensitivity in the root response to P deficiency. The OE lines had a shorter SR length, lower LR density, and greater RH density than WT plants under control. However, the LR and RH densities in the OE lines were similar to those in WT plants under LP. Compared to WT plants, overexpression of OsPIN2 had a shorter root length through decreased root cell elongation under control and LP. Surprisingly, overexpression of OsPIN2 might increase auxin distribution in epidermis of root, resulting in greater RH formation but less LR development in OE plants than in WT plants in the control condition but levels similar of these under LP. These results suggest that higher OsPIN2 expression regulates rice root growth and development maybe by changing auxin distribution in roots under LP condition.
PMID: 31627334
Int J Mol Sci , IF:4.556 , 2019 Oct , V20 (19) doi: 10.3390/ijms20194923
Phytohormones (Auxin, Gibberellin) and ACC Deaminase In Vitro Synthesized by the Mycoparasitic Trichoderma DEMTkZ3A0 Strain and Changes in the Level of Auxin and Plant Resistance Markers in Wheat Seedlings Inoculated with this Strain Conidia.
Department of Environmental Microbiology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland. jolanta.jaroszuk-scisel@poczta.umcs.lublin.pl.; Department of Environmental Microbiology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland. renata.tyskiewicz@poczta.umcs.lublin.pl.; Military Institute of Hygiene and Epidemiology, Lubelska St. 2, 24-100 Pulawy, Poland. renata.tyskiewicz@poczta.umcs.lublin.pl.; Department of Environmental Microbiology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland. artur.nowak@poczta.umcs.lublin.pl.; Department of Environmental Microbiology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland. ozimek@poczta.umcs.lublin.pl.; Department of Environmental Microbiology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland. majewska@poczta.umcs.lublin.pl.; Department of Plant Physiology, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland. agnieszka.hanaka@poczta.umcs.lublin.pl.; LUKASIEWICZ Research Network-New Chemical Syntheses Institute, Tysiaclecia Panstwa Polskiego Ave. 13a, 24-110 Pulawy, Poland. katarzyna.tyskiewicz@ins.pulawy.pl.; Department of Biochemistry, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland. anna.pawlik@poczta.umcs.lublin.pl.; Department of Biochemistry, Maria Curie-Sklodowska University, Akademicka St. 19, 20-033 Lublin, Poland. gjanusz@poczta.umcs.lublin.pl.
Both hormonal balance and plant growth may be shaped by microorganisms synthesizing phytohormones, regulating its synthesis in the plant and inducing plant resistance by releasing elicitors from cell walls (CW) by degrading enzymes (CWDE). It was shown that the Trichoderma DEMTkZ3A0 strain, isolated from a healthy rye rhizosphere, colonized the rhizoplane of wheat seedlings and root border cells (RBC) and caused approximately 40% increase of stem weight. The strain inhibited (in over 90%) the growth of polyphagous Fusarium spp. (F. culmorum, F. oxysporum, F. graminearum) phytopathogens through a mechanism of mycoparasitism. Chitinolytic and glucanolytic activity, strongly stimulated by CW of F. culmorum in the DEMTkZ3A0 liquid culture, is most likely responsible for the lysis of hyphae and macroconidia of phytopathogenic Fusarium spp. as well as the release of plant resistance elicitors. In DEMTkZ3A0 inoculated plants, an increase in the activity of the six tested plant resistance markers and a decrease in the concentration of indoleacetic acid (IAA) auxin were noted. IAA and gibberellic acid (GA) but also the 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (ACCD) enzyme regulating ethylene production by plant were synthesized by DEMTkZ3A0 in the liquid culture. IAA synthesis was dependent on tryptophan and negatively correlated with temperature, whereas GA synthesis was positively correlated with the biomass and temperature.
PMID: 31590281
Microorganisms , IF:4.152 , 2019 Oct , V7 (11) doi: 10.3390/microorganisms7110490
The Endophytic Fungus Chaetomium cupreum Regulates Expression of Genes Involved in the Tolerance to Metals and Plant Growth Promotion in Eucalyptus globulus Roots.
Laboratorio de Biorremediacion, Facultad de Ciencias Agropecuarias y Forestales, Universidad de La Frontera, Francisco Salazar 01145, Temuco, Chile.; Programa de Doctorado en Ciencias Mencion Biologia Celular y Molecular Aplicada, Universidad de La Frontera, Francisco Salazar 01145, Temuco, Chile.; Centro de Biotecnologia Vegetal, Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile.
The endophytic strain Chaetomium cupreum isolated from metal-contaminated soil was inoculated in Eucalyptus globulus roots to identify genes involved in metal stress response and plant growth promotion. We analyzed the transcriptome of E. globulus roots inoculated with C. cupreum. De novo sequencing, assembly, and analysis were performed to identify molecular mechanisms involved in metal stress tolerance and plant growth promotion. A total of 393,371,743 paired-end reads were assembled into 135,155 putative transcripts. It was found that 663 genes significantly changed their expression in the presence of treatment, of which 369 were up-regulated and 294 were down-regulated. We found differentially expressed genes (DEGs) encoding metal transporters, transcription factors, stress and defense response proteins, as well as DEGs involved in auxin biosynthesis and metabolism. Our results showed that the inoculation of C. cupreum enhanced tolerance to metals and growth promotion on E. globulus. This study provides new information to understand molecular mechanisms involved in plant-microbe interactions under metals stress.
PMID: 31717780
Biomolecules , IF:4.082 , 2019 Oct , V9 (10) doi: 10.3390/biom9100623
Epigenetic Regulation of Auxin Homeostasis.
Department of Forest Genetics and Plant Physiology, Umea Plant Science Centre, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden. eduardo.mateo.bonmati@slu.se.; Department of Forest Genetics and Plant Physiology, Umea Plant Science Centre, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden. ruben.casanova.saez@slu.se.; Department of Forest Genetics and Plant Physiology, Umea Plant Science Centre, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden. Karin.Ljung@slu.se.
Epigenetic regulation involves a myriad of mechanisms that regulate the expression of loci without altering the DNA sequence. These different mechanisms primarily result in modifications of the chromatin topology or DNA chemical structure that can be heritable or transient as a dynamic response to environmental cues. The phytohormone auxin plays an important role in almost every aspect of plant life via gradient formation. Auxin maxima/minima result from a complex balance of metabolism, transport, and signaling. Although epigenetic regulation of gene expression during development has been known for decades, the specific mechanisms behind the spatiotemporal dynamics of auxin levels in plants are only just being elucidated. In this review, we gather current knowledge on the epigenetic mechanisms regulating the expression of genes for indole-3-acetic acid (IAA) metabolism and transport in Arabidopsis and discuss future perspectives of this emerging field.
PMID: 31635281
Plant Cell Physiol , IF:4.062 , 2019 Oct , V60 (10) : P2343-2355 doi: 10.1093/pcp/pcz132
Genome-Wide Transcript Profiling Reveals an Auxin-Responsive Transcription Factor, OsAP2/ERF-40, Promoting Rice Adventitious Root Development.
Department of Biotechnology, Indian Institute of Technology, Roorkee, Uttarakhand, India.; School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India.; School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India.
Unlike dicots, the robust root system in grass species largely originates from stem base during postembryonic development. The mechanisms by which plant hormone signaling pathways control the architecture of adventitious root remain largely unknown. Here, we studied the modulations in global genes activity in developing rice adventitious root by genome-wide RNA sequencing in response to external auxin and cytokinin signaling cues. We further analyzed spatiotemporal regulations of key developmental regulators emerged from our global transcriptome analysis. Interestingly, some of the key cell fate determinants such as homeodomain transcription factor (TF), OsHOX12, no apical meristem protein, OsNAC39, APETALA2/ethylene response factor, OsAP2/ERF-40 and WUSCHEL-related homeobox, OsWOX6.1 and OsWOX6.2, specifically expressed in adventitious root primordia. Functional analysis of one of these regulators, an auxin-induced TF containing AP2/ERF domain, OsAP2/ERF-40, demonstrates its sufficiency to confer the adventitious root fate. The ability to trigger the root developmental program is largely attributed to OsAP2/ERF-40-mediated dose-dependent transcriptional activation of genes that can facilitate generating effective auxin response, and OsERF3-OsWOX11-OsRR2 pathway. Our studies reveal gene regulatory network operating in response to hormone signaling pathways and identify a novel TF regulating adventitious root developmental program, a key agronomically important quantitative trait, upstream of OsERF3-OsWOX11-OsRR2 pathway.
PMID: 31318417
Appl Environ Microbiol , IF:4.016 , 2019 Oct , V85 (19) doi: 10.1128/AEM.00383-19
Plantibacter flavus, Curtobacterium herbarum, Paenibacillus taichungensis, and Rhizobium selenitireducens Endophytes Provide Host-Specific Growth Promotion of Arabidopsis thaliana, Basil, Lettuce, and Bok Choy Plants.
University of Toronto Scarborough, Toronto, Ontario, Canada.; University of Toronto Scarborough, Toronto, Ontario, Canada fulthorpe@utsc.utoronto.ca.
A collection of bacterial endophytes isolated from stem tissues of plants growing in soils highly contaminated with petroleum hydrocarbons were screened for plant growth-promoting capabilities. Twenty-seven endophytic isolates significantly improved the growth of Arabidopsis thaliana plants in comparison to that of uninoculated control plants. The five most beneficial isolates, one strain each of Curtobacterium herbarum, Paenibacillus taichungensis, and Rhizobium selenitireducens and two strains of Plantibacter flavus were further examined for growth promotion in Arabidopsis, lettuce, basil, and bok choy plants. Host-specific plant growth promotion was observed when plants were inoculated with the five bacterial strains. P. flavus strain M251 increased the total biomass and total root length of Arabidopsis plants by 4.7 and 5.8 times, respectively, over that of control plants and improved lettuce and basil root growth, while P. flavus strain M259 promoted Arabidopsis shoot and root growth, lettuce and basil root growth, and bok choy shoot growth. A genome comparison between P. flavus strains M251 and M259 showed that both genomes contain up to 70 actinobacterial putative plant-associated genes and genes involved in known plant-beneficial pathways, such as those for auxin and cytokinin biosynthesis and 1-aminocyclopropane-1-carboxylate deaminase production. This study provides evidence of direct plant growth promotion by Plantibacter flavus IMPORTANCE The discovery of new plant growth-promoting bacteria is necessary for the continued development of biofertilizers, which are environmentally friendly and cost-efficient alternatives to conventional chemical fertilizers. Biofertilizer effects on plant growth can be inconsistent due to the complexity of plant-microbe interactions, as the same bacteria can be beneficial to the growth of some plant species and neutral or detrimental to others. We examined a set of bacterial endophytes isolated from plants growing in a unique petroleum-contaminated environment to discover plant growth-promoting bacteria. We show that strains of Plantibacter flavus exhibit strain-specific plant growth-promoting effects on four different plant species.
PMID: 31350315
Sci Rep , IF:3.998 , 2019 Oct , V9 (1) : P14511 doi: 10.1038/s41598-019-50962-y
The explant developmental stage profoundly impacts small RNA-mediated regulation at the dedifferentiation step of maize somatic embryogenesis.
Departamento de Bioquimica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CDMX, 04510, Mexico.; Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO, 63132, USA.; Division of Plant Sciences, University of Missouri, Columbia, Missouri, 65211, USA.; Departamento de Bioquimica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, CDMX, 04510, Mexico. cesy@unam.mx.
Maize somatic embryogenesis (SE) requires the induction of embryogenic callus and establishment of proliferation before plant regeneration. The molecular mechanisms underlying callus embryogenic potential are not well understood. Here we explored the role of small RNAs (sRNAs) and the accumulation of their target transcripts in maize SE at the dedifferentiation step using VS-535 zygotic embryos collected at distinct developmental stages and displaying contrasting in vitro embryogenic potential and morphology. MicroRNAs (miRNAs), trans-acting siRNAs (tasiRNAs), heterochromatic siRNAs (hc-siRNAs) populations and their RNA targets were analyzed by high-throughput sequencing. Abundances of specific miRNAs, tasiRNAs and targets were validated by qRT-PCR. Unique accumulation patterns were found for immature embryo at 15 Days After Pollination (DAP) and for the callus induction from this explant, as compared to 23 DAP and mature embryos. miR156, miR164, miR166, tasiARFs and the 24 nt hc-siRNAs displayed the most strikingly different patterns between explants and during dedifferentiation. According to their role in auxin responses and developmental cues, we conclude that sRNA-target regulation operating within the 15 DAP immature embryo explant provides key molecular hints as to why this stage is relevant for callus induction with successful proliferation and plant regeneration.
PMID: 31601893
Sci Rep , IF:3.998 , 2019 Oct , V9 (1) : P14384 doi: 10.1038/s41598-019-50970-y
Static magnetic field regulates Arabidopsis root growth via auxin signaling.
Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China.; Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.; Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, 200241, China.; Heye Health Industrial Research Institute of Zhejiang Heye Health Technology, Anji, Zhejiang, 313300, China.; School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China.; Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China. huangjr@shnu.edu.cn.
Static magnetic field (SMF) plays important roles in biological processes of many living organisms. In plants, however, biological significance of SMF and molecular mechanisms underlying SMF action remain largely unknown. To address these questions, we treated Arabidopsis young seedlings with different SMF intensities and directions. Magnetic direction from the north to south pole was adjusted in parallel (N0) with, opposite (N180) and perpendicular to the gravity vector. We discovered that root growth is significantly inhanced by 600 mT treatments except for N180, but not by any 300 mT treatments. N0 treatments lead to more active cell division of the meristem, and higher auxin content that is regulated by coordinated expression of PIN3 and AUX1 in root tips. Consistently, N0-promoted root growth disappears in pin3 and aux1 mutants. Transcriptomic and gene ontology analyses revealed that in roots 85% of the total genes significantly down-regulated by N0 compared to untreatment are enriched in plastid biological processes, such as metabolism and chloroplast development. Lastly, no difference in root length is observed between N0-treated and untreated roots of the double cryptochrome mutant cry1 cry2. Taken together, our data suggest that SMF-regulated root growth is mediated by CRY and auxin signaling pathways in Arabidopsis.
PMID: 31591431
Viruses , IF:3.816 , 2019 Oct , V11 (11) doi: 10.3390/v11110992
Root Transcriptomic Analysis Reveals Global Changes Induced by Systemic Infection of Solanum lycopersicum with Mild and Severe Variants of Potato Spindle Tuber Viroid.
Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland. annag@ibb.waw.pl.; Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland. anetaw@ibb.waw.pl.; Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland. AnnaFogtman@ibb.waw.pl.; Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland. mlirski@ibb.waw.pl.; Institute of Biochemistry and Biophysics Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland. annags7@wp.pl.
Potato spindle tuber viroid (PSTVd) causes systemic infection in plant hosts. There are many studies on viroid-host plant interactions, but they have predominantly focused on the aboveground part of the plant. Here, we investigated transcriptomic profile changes in tomato roots systemically infected with mild or severe PSTVd variants using a combined microarray/RNA-seq approach. Analysis indicated differential expression of genes related to various Gene Ontology categories depending on the stage of infection and PSTVd variant. A majority of cell-wall-related genes were down-regulated at early infection stages, but at the late stage, the number of up-regulated genes increased significantly. Along with observed alterations of many lignin-related genes, performed lignin quantification indicated their disrupted level in PSTVd-infected roots. Altered expression of genes related to biosynthesis and signaling of auxin and cytokinin, which are crucial for lateral root development, was also identified. Comparison of both PSTVd infections showed that transcriptional changes induced by the severe variant were stronger than those caused by the mild variant, especially at the late infection stage. Taken together, we showed that similarly to aboveground plant parts, PSTVd infection in the underground tissues activates the plant immune response.
PMID: 31671783
Genes (Basel) , IF:3.759 , 2019 Oct , V10 (10) doi: 10.3390/genes10100809
Overexpression of OsPT8 Increases Auxin Content and Enhances Tolerance to High-Temperature Stress in Nicotiana tabacum.
College of tobacco Science, Henan Agricultural University, Zhengzhou 450002, China.; Zunyi Branch of Guizhou Tobacco Company, Zunyi 563000, China.; College of tobacco Science, Henan Agricultural University, Zhengzhou 450002, China. jiahongfang@henau.edu.cn.
Temperature is a primary factor affecting the rate of plant development; as the climate warms, extreme temperature events are likely to increasingly affect agriculture. Understanding how to improve crop tolerance to heat stress is a key concern. Wild plants have evolved numerous strategies to tolerate environmental conditions, notably the regulation of root architecture by phytohormones, but the molecular mechanisms of stress resistance are unclear. In this study, we showed that high temperatures could significantly reduce tobacco biomass and change its root architecture, probably through changes in auxin content and distribution. Overexpression of the OsPT8 phosphate transporter enhanced tobacco tolerance to high-temperature stress by changing the root architecture and increased the antioxidant ability. Molecular assays suggested that overexpression of OsPT8 in tobacco significantly increased the expression of auxin synthesis genes NtYUCCA 6, 8 and auxin efflux carriers genes NtPIN 1,2 under high-temperature stress. We also found that the expression levels of auxin response factors NtARF1 and NtARF2 were increased in OsPT8 transgenic tobacco under high-temperature stress, suggesting that OsPT8 regulates auxin signaling in response to high-temperature conditions. Our findings provided new insights into the molecular mechanisms of plant stress signaling and showed that OsPT8 plays a key role in regulating plant tolerance to stress conditions.
PMID: 31615148
Plant Physiol Biochem , IF:3.72 , 2019 Oct , V143 : P351-363 doi: 10.1016/j.plaphy.2019.09.015
Supplementation of Trichoderma improves the alteration of nutrient allocation and transporter genes expression in rice under nutrient deficiencies.
Division of Microbial Technology, Council of Scientific and Industrial Research- National Botanical Research Institute, Lucknow, India.; Division of Microbial Technology, Council of Scientific and Industrial Research- National Botanical Research Institute, Lucknow, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India.; Division of Microbial Technology, Council of Scientific and Industrial Research- National Botanical Research Institute, Lucknow, India; Department of Botany, Lucknow University, Hasanganj, Lucknow, 226 007, India.; Division of Microbial Technology, Council of Scientific and Industrial Research- National Botanical Research Institute, Lucknow, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India. Electronic address: mishra.a@nbri.res.in.
Nutrients are the finite natural resources that are essential for productivity and development of rice and its deficiency causes compromised yield along with reduced immunity against several biotic and abiotic stresses. In this study, the potential of Trichoderma reesei has been investigated as a biofertilizer (BF) to ameliorate nutrient stress in different rice cultivars at physiological, biochemical and molecular levels. The results indicated that cultivar Heena is much more compatible with BF as compared to cultivar Kiran at 50% nutrient limiting condition. Enhancement in physiological attributes and photosynthetic pigments were observed in BF treated Heena seedlings. The localization of biofertilizer in treated roots was further validated by scanning electron micrographs. This result correlated well with the higher levels of Indole acetic acid and Gibberellic acid in biofertilizer treated rice. Similarly, the uptake of micro-nutrients such as Fe, Co, Cu and Mo was found to be 1.4-1.9 fold higher respectively in BF treated Heena seedlings under 50% nutrient deficient condition. Furthermore, different stress ameliorating enzymes Guaiacol peroxidase, Super oxide dismutase, Total Phenolic Content, Phenol Peroxidase, Phenylalanine ammonia lyase and Ascorbate peroxidase in Heena seedlings were also increased by 1.8, 1.4, 1.2, 2.4, 1.2, and 8.3-fold respectively, at 50% nutrient deficient condition. The up-regulation of different micro and macro-nutrients allocation and accumulation; metal tolerance related; auxin synthesis genes in BF treated Heena as compared to 50% nutrient deficient condition was further supported by our findings that the application of biofertilizer efficiently ameliorated the deficiency of nutrients in rice.
PMID: 31541990
Plant Physiol Biochem , IF:3.72 , 2019 Oct , V143 : P203-211 doi: 10.1016/j.plaphy.2019.09.002
Chitosan microparticles improve tomato seedling biomass and modulate hormonal, redox and defense pathways.
Instituto de Investigaciones Biologicas, UE-CONICET-UNMdP, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina.; Gihon Laboratorios Quimicos SRL, Mar del Plata, Argentina.; Instituto de Investigacion en Ciencia & Tecnologia de Materiales INTEMA, UE-CONICET-UNMdP, Grupo Materiales Compuestos Termoplasticos, Facultad de Ingenieria, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina.; Instituto de Investigaciones Biologicas, UE-CONICET-UNMdP, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina. Electronic address: casalong@mdp.edu.ar.
Agrobiotechnology challenges involve the generation of new sustainable bioactives with emerging properties as plant biostimulants with reduced environment impact. We analyzed the potential use of recently developed chitosan microparticles (CS-MP) as growth promoters of tomato which constitutes one of the most consumed vegetable crops worldwide. Treatments of tomato seeds with CS-MP improved germination and vigor index. In addition, CS-MP sustained application triggered an improvement in root and shoot biomass reinforcing tomato performance before transplanting. The level of reactive oxygen species (ROS), antioxidant enzyme activities and defense protein markers were modulated by CS-MP treatment in tomato plantlets. Analyses of ARR5:GUS and DR5:GUS transgenic reporter tomato lines highlighted the participation of cytokinin and auxin signaling pathways during tomato root promotion mediated by CS-MP. Our findings claim a high commercial potential of CS-MP to be incorporated as a sustainable input for tomato production.
PMID: 31518851
Plant Physiol Biochem , IF:3.72 , 2019 Oct , V143 : P109-118 doi: 10.1016/j.plaphy.2019.08.029
LED lamps enhance somatic embryo maturation in association with the differential accumulation of proteins in the Carica papaya L. 'Golden' embryogenic callus.
Laboratorio de Biotecnologia, Centro de Biociencias e Biotecnologia (CBB), Universidade Estadual Do Norte Fluminense Darcy Ribeiro (UENF), Campos Dos Goytacazes, RJ, 28013-602, Brazil; Unidade de Biologia Integrativa, Setor de Genomica e Proteomica, UENF, Campos Dos Goytacazes, RJ, 28013-602, Brazil.; Laboratorio de Biologia Celular e Tecidual, CBB, UENF, Campos Dos Goytacazes, RJ, Brazil.; Laboratorio de Biotecnologia, Centro de Biociencias e Biotecnologia (CBB), Universidade Estadual Do Norte Fluminense Darcy Ribeiro (UENF), Campos Dos Goytacazes, RJ, 28013-602, Brazil; Unidade de Biologia Integrativa, Setor de Genomica e Proteomica, UENF, Campos Dos Goytacazes, RJ, 28013-602, Brazil. Electronic address: vanildo@uenf.br.
The use of light-emitting diode (LED) lamps has been shown to be a promising approach for improving somatic embryo maturation during somatic embryogenesis. The aim of this work was to study the influence of the light source on somatic embryo differentiation and its relationship with the differential abundance of proteins in the Carica papaya L. 'Golden' embryogenic callus at 14 days of maturation. The white plus medium-blue (WmB) LED and fluorescent lamp treatments produced an average of 82.4 and 47.6 cotyledonary somatic embryos per callus, respectively. A shotgun proteomics analysis revealed 28 upaccumulated and 7 downaccumulated proteins. The proteins upaccumulated in the embryogenic callus matured under the WmB LED lamp compared with that matured under the fluorescent lamp included indole-3-acetic acid-amido synthetase (GH3) and actin-depolymerizing factor 2 (ADF2), which are involved in the regulation of auxin levels by auxin conjugation and transport. Additionally, proteins related to energy production (aconitate, ADH1, GAPCp, PKp and TPI), cell wall remodeling (PG and GLPs), and intracellular trafficking (NUP50A, IST1, small GTPases and H(+)-PPase) showed significantly higher abundance in the embryogenic callus incubated under the WmB LED lamp than in that incubated under the fluorescent lamp. The results showed that the WmB LED lamp improved somatic embryo maturation in association with the differential accumulation of proteins in the C. papaya 'Golden' embryogenic callus.
PMID: 31491701
Mol Plant Microbe Interact , IF:3.696 , 2019 Oct , V32 (10) : P1429-1447 doi: 10.1094/MPMI-05-19-0132-R
Enhancement of ABA Sensitivity Through Conditional Expression of the ARF10 Gene in Brassica juncea Reveals Fertile Plants with Tolerance Against Alternaria brassicicola.
Division of Plant Biology, Bose Institute, Centenary Campus P-1/12 C.I.T., Scheme-VIIM Kolkata, 700054, West Bengal, India.; Institut Curie, CNRS UMR 3348, Orsay, France.; Plant and Microbial biotechnology, Institute of Life Sciences (ILS), NALCO Square, Bhubaneswar, 751023, Odisha, India.; Department of Botany, Sister Nivedita Government General Degree College for Girls, 20B Judge's Court Road, Hastings House, Alipore, Kolkata, 700027, West Bengal, India.; Department of Genetics, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India.
Concomitant increase of auxin-responsive factors ARF16 and ARF17, along with enhanced expression of ARF10 in resistant Sinapis alba compared with that in susceptible Brassica juncea upon challenge with Alternaria brassicicola, revealed that abscisic acid (ABA)-auxin crosstalk is a critical factor for resistance response. Here, we induced the ABA response through conditional expression of ARF10 in B. juncea using the A. brassicicola-inducible GH3.3 promoter. Induced ABA sensitivity caused by conditional expression of ARF10 in transgenic B. juncea resulted in tolerance against A. brassicicola and led to enhanced expression of several ABA-responsive genes without affecting the auxin biosynthetic gene expression. Compared with ABI3 and ABI4, ABI5 showed maximum upregulation in the most tolerant transgenic lines upon pathogen challenge. Moreover, elevated expression of ARF10 by different means revealed a direct correlation between ARF10 expression and the induction of ABI5 protein in B. juncea. Through in vitro DNA-protein experiments and chromosome immunoprecipitation using the ARF10 antibody, we demonstrated that ARF10 interacts with the auxin-responsive elements of the ABI5 promoter. This suggests that ARF10 may function as a modulator of ABI5 to induce ABA sensitivity and mediate the resistance response against A. brassicicola.
PMID: 31184524
BMC Genomics , IF:3.594 , 2019 Oct , V20 (1) : P766 doi: 10.1186/s12864-019-6151-x
Proteomic analysis showing the signaling pathways involved in the rhizome enlargement process in Nelumbo nucifera.
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.; University of Chinese Academy of Sciences, Beijing, 100049, China.; State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China.; State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China. limit@hubu.edu.cn.; State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China. yangpf@wbgcas.cn.
BACKGROUND: Rhizome is the storage underground stem of lotus (Nelumbo nucifera), which is enlarged before winter season and could be used for asexual propagation. In addition, the enlarged rhizome is a nutritional vegetable with abundant starch, proteins, and vitamins. Enlargement of lotus rhizome is not only significance for itself to survive from the cold winter, but also important for its economic value. RESULTS: To explore the mechanism underlying its enlargement, integrative analyses of morphology, physiology and proteomics were conducted on the rhizome at stolon, middle, and enlarged stages. Morphological observation and physiological analyses showed that rhizomes were gradually enlarged during this process, in which the starch accumulation was also initiated. Quantitative proteomic analysis on the rhizomes at these three stages identified 302 stage-specific proteins (SSPs) and 172 differently expressed proteins (DEPs), based on which GO and KEGG enrichment analyses were conducted. The results indicated that light and auxin signal might be transduced through secondary messenger Ca(2+), and play important roles in lotus rhizome enlargement. CONCLUSION: These results will provide new insights into understanding the mechanism of lotus rhizome enlargement. Meanwhile, some candidate genes might be useful for further studies on this process, as well as breeding of rhizome lotus.
PMID: 31640547
BMC Genomics , IF:3.594 , 2019 Oct , V20 (1) : P747 doi: 10.1186/s12864-019-6090-6
Genetic mechanisms in the repression of flowering by gibberellins in apple (Malus x domestica Borkh.).
Department of Horticulture and Graduate Program in Plant Breeding, Genetics, and Biotechnology, Michigan State University, 390 Plant and Soil Science Building, 1066 Bogue St., East Lansing, MI, 48824, USA.; Department of Horticulture and Graduate Program in Plant Breeding, Genetics, and Biotechnology, Michigan State University, 390 Plant and Soil Science Building, 1066 Bogue St., East Lansing, MI, 48824, USA. vannocke@msu.edu.
BACKGROUND: Gibberellins (GAs) can have profound effects on growth and development in higher plants. In contrast to their flowering-promotive role in many well-studied plants, GAs can repress flowering in woody perennial plants such as apple (Malus x domestica Borkh.). Although this effect of GA on flowering is intriguing and has commercial importance, the genetic mechanisms linking GA perception with flowering have not been well described. RESULTS: Application of a mixture of bioactive GAs repressed flower formation without significant effect on node number or shoot elongation. Using Illumina-based transcriptional sequence data and a newly available, high-quality apple genome sequence, we generated transcript models for genes expressed in the shoot apex, and estimated their transcriptional response to GA. GA treatment resulted in downregulation of a diversity of genes participating in GA biosynthesis, and strong upregulation of the GA catabolic GA2 OXIDASE genes, consistent with GA feedback and feedforward regulation, respectively. We also observed strong downregulation of numerous genes encoding potential GA transporters and receptors. Additional GA-responsive genes included potential components of cytokinin (CK), abscisic acid (ABA), brassinosteroid, and auxin signaling pathways. Finally, we observed rapid and strong upregulation of both of two copies of a gene previously observed to inhibit flowering in apple, MdTFL1 (TERMINAL FLOWER 1). CONCLUSION: The rapid and robust upregulation of genes associated with GA catabolism in response to exogenous GA, combined with the decreased expression of GA biosynthetic genes, highlights GA feedforward and feedback regulation in the apple shoot apex. The finding that genes with potential roles in GA metabolism, transport and signaling are responsive to GA suggests GA homeostasis may be mediated at multiple levels in these tissues. The observation that TFL1-like genes are induced quickly in response to GA suggests they may be directly targeted by GA-responsive transcription factors, and offers a potential explanation for the flowering-inhibitory effects of GA in apple. These results provide a context for investigating factors that may transduce the GA signal in apple, and contribute to a preliminary genetic framework for the repression of flowering by GAs in a woody perennial plant.
PMID: 31619173
Plant Sci , IF:3.591 , 2019 Oct , V287 : P110191 doi: 10.1016/j.plantsci.2019.110191
Genome-wide identification, expression and functional analysis of Populus xylogen-like genes.
School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.; School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China. Electronic address: jiehuawang@tju.edu.cn.
As an extracellular arabinogalactan protein (AGP) containing a non-specific lipid transfer protein (nsLTP) domain, xylogen mediates the local intercellular communication required for tracheary element (TE) differentiation in Zinnia cell culture. Although XYLP (xylogen-like protein) gene families have been reported in Arabidopsis and rice, no comprehensive analysis has been performed in woody plants. In this work, 31 XYLP genes in five phylogenetic groups were identified from Populus trichocarpa genome and a comprehensive bioinformatic analysis including gene and protein structures, chromosomal locations and duplication events were conducted. In-silico data and qRT-PCR results indicated that PtXYLP1 is predominantly expressed in poplar apex, young leaves and roots, while PtXYLP2 is uniformly expressed across a variety of tissues with a low abundance. Analysis on PtXYLP1pro:GUS and PtXYLP2pro:GUS in Arabidopsis revealed their differential expression patterns during seed germination and specific inductions by exogenously applied phytohormones including auxin, cytokinin and GA. When overexpressed in Arabidopsis, PtXYLP1 but not PtXYLP2 resulted in cotyledons with defective venation patterns and interrupted secondary (2 degrees ) vein loops, which phenotype was underpinned by the down-regulation of genes indispensably required by embryonic venation development at procambium and/or vessel level.
PMID: 31481222
Plant Sci , IF:3.591 , 2019 Oct , V287 : P110175 doi: 10.1016/j.plantsci.2019.110175
Proteomic profiling of root system development proteins in chrysanthemum overexpressing the CmTCP20 gene.
National Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China.; National Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China. Electronic address: sunxia65@sina.com.; National Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China. Electronic address: zcs@sdau.edu.cn.
Plant root systems ensure the efficient absorption of water and nutrients and provide anchoring into the soil. Although root systems are a highly plastic set of traits that vary both between and among species, the basic root system morphology is controlled by inherent genetic factors. TCP20 has been identified as a key regulator of root development in plants, and yet its underlying mechanism has not been fully elucidated, especially in chrysanthemum. We found that overexpression of the CmTCP20 gene promoted both adventitious and lateral root development in chrysanthemum. To get further insight into the molecular mechanisms controlling root system development, we conducted a study employing tandem mass tag proteomic to characterize the differential root system development proteomes from CmTCP20-overexpressing and wild-type chrysanthemum root samples. Of the proteins identified, 234 proteins were found to be differentially abundant (>1.5-fold cut off, p < 0.05) in CmTCP20-overexpressing versus wild-type chrysanthemum root samples. Functional enrichment analysis indicated that the CmTCP20 gene may participate in "phytohormone signal transduction". Our findings provide a valuable perspective on the mechanisms of both adventitious and lateral root development via CmTCP20 modulation at the proteome level in chrysanthemum.
PMID: 31481217
Plant Sci , IF:3.591 , 2019 Oct , V287 : P110168 doi: 10.1016/j.plantsci.2019.110168
Gibberellic acid inhibition of tillering in tall fescue involving crosstalks with cytokinins and transcriptional regulation of genes controlling axillary bud outgrowth.
College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. Electronic address: zhuanglili2001@163.com.; College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. Electronic address: 2016120010@njau.edu.cn.; College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. Electronic address: 2015220003@njau.edu.cn.; College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. Electronic address: nauyjj@njau.edu.cn.; College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. Electronic address: nauyzm@njau.edu.cn.; Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ, 08901, USA. Electronic address: huang@aesop.rutgers.edu.
Tiller production in grass species is controlled by both axillary bud initiation and bud outgrowth, which may be regulated by plant hormones. However, how gibberellic acid (GA) affects tillering in perennial grass species is still unclear. This study aims to elucidate the roles and the underlying mechanisms of GA in regulating tiller development. Tall fescue seedlings were treated with different concentrations of GA3 by foliar application, dose-dependent inhibitory effects of GA on tiller production were observed. GA3 (25muM) slowed down the transition from axillary buds to tillers by specifically inhibiting the outgrowth of axillary buds. GA-inhibition of tillering were not related to endogenous content for auxin or strigolactone, but was mainly due to the antagonistic interaction with cytokinins (CK), as shown by the decreased CK content and up-regulation expression of CK degradation genes in GA3-treated plants. Furthermore, GA could act through regulating the expression of FaTB1 specifically expressed in axillary buds to repress bud outgrowth. These results provide insights for the regulatory mechanisms of GA for tiller bud outgrowth through crosstalks with CK and signaling of FaTB1 expression.
PMID: 31481214
Plant Sci , IF:3.591 , 2019 Oct , V287 : P110176 doi: 10.1016/j.plantsci.2019.110176
IAOx induces the SUR phenotype and differential signalling from IAA under different types of nitrogen nutrition in Medicago truncatula roots.
Department of Sciences-Institute of Multidisciplinary Applied Biology Research-IMAB, Public University of Navarre, Avenida de Pamplona 123, 31192 Mutilva, Spain. Electronic address: javier.buezo@unavarra.es.; Basque Centre for Climate Change (BC3), 48640 Leioa, Spain; University of the Basque Country, UPV/EHU, Sarriena s/n, Apdo. 644, 48080 Bilbao, Spain. Electronic address: raquel.esteban@ehu.es.; Department of Sciences-Institute for Advance Materials INAMAT, Public University of Navarre, Campus de Arrosadia, 31006 Pamplona, Spain. Electronic address: alfonso.cornejo@unavarra.es.; Department of Sciences-Institute of Multidisciplinary Applied Biology Research-IMAB, Public University of Navarre, Avenida de Pamplona 123, 31192 Mutilva, Spain. Electronic address: pedro.lopez@unavarra.es.; University of the Basque Country, UPV/EHU, Sarriena s/n, Apdo. 644, 48080 Bilbao, Spain; Ikerbasque, Basque Foundation for Science, E-48011 Bilbao, Spain. Electronic address: daniel.marino@ehu.eus.; Department of Sciences-Institute of Multidisciplinary Applied Biology Research-IMAB, Public University of Navarre, Avenida de Pamplona 123, 31192 Mutilva, Spain. Electronic address: alejandro.chamizo@unavarra.es.; Department of Sciences-Institute for Advance Materials INAMAT, Public University of Navarre, Campus de Arrosadia, 31006 Pamplona, Spain. Electronic address: mjg@unavarra.es.; Department of Sciences-Institute for Advance Materials INAMAT, Public University of Navarre, Campus de Arrosadia, 31006 Pamplona, Spain. Electronic address: merino@unavarra.es.; Department of Sciences-Institute of Multidisciplinary Applied Biology Research-IMAB, Public University of Navarre, Avenida de Pamplona 123, 31192 Mutilva, Spain. Electronic address: jose.moran@unavarra.es.
Indole-3-acetaldoxime (IAOx) is a particularly relevant molecule as an intermediate in the pathway for tryptophan-dependent auxin biosynthesis. The role of IAOx in growth-signalling and root phenotype is poorly studied in cruciferous plants and mostly unknown in non-cruciferous plants. We synthesized IAOx and applied it to M. truncatula plants grown axenically with NO3(-), NH4(+) or urea as the sole nitrogen source. During 14 days of growth, we demonstrated that IAOx induced an increase in the number of lateral roots, especially under NH4(+) nutrition, while elongation of the main root was inhibited. This phenotype is similar to the phenotype known as "superroot" previously described in SUR1- and SUR2-defective Arabidopsis mutants. The effect of IAOx, IAA or the combination of both on the root phenotype was different and dependent on the type of N-nutrition. Our results also showed the endogenous importance of IAOx in a legume plant in relation to IAA metabolism, and suggested IAOx long-distance transport depending on the nitrogen source provided. Finally, our results point out to CYP71A as the major responsible enzymes for IAA synthesis from IAOx, while they exclude indole-3-acetaldehyde oxidases.
PMID: 31481210
Plant Sci , IF:3.591 , 2019 Oct , V287 : P110198 doi: 10.1016/j.plantsci.2019.110198
Insights into the role of phytohormones regulating pAtNIP5;1 activity and boron transport in Arabidopsis thaliana.
Departamento de Biologia, Universidad Autonoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049, Madrid, Spain.; IPK-Leibniz Institute of Plant Genetics and Crop Plant Research, Department of Physiology and Cell Biology, 06466, Gatersleben, Germany.; Departamento de Biologia, Universidad Autonoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049, Madrid, Spain. Electronic address: maria.reguera@uam.es.
Aiming to counteract B deficiency impacts, plants have developed different strategies in order to reach an optimal growth in soils with limited B availability. These include B transport mechanisms that involves a facilitated transport, via channel proteins, and a high-affinity active transport driven by borate transporters. The AtNIP5;1 channel protein is a member of Major Intrinsic Protein family which facilitates B influx into the roots under low B supply. In order to explore the phytohormone-dependent regulation of AtNIP5;1, the effects of abscisic acid (ABA), ethylene, auxins and cytokinins on the activity of AtNIP5;1 promoter were evaluated using the reporter line pNIP5;1-GUS. The results show that ABA treatment increased pAtNIP5;1 activity. Besides, a larger B uptake was found following ABA treatment under B deficiency suggesting a role of ABA inducing B uptake. The ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) caused an induction of AtNIP5;1 expression although did not correlate with higher B concentrations nor with an improvement in root growth. On the contrary, auxins and cytokinins caused slight changes in pAtNIP5;1 induction. Altogether, these results show a regulatory role of phytohormones in AtNIP5;1 promoter what may affect B transport. The herein provided information may contribute to better understand the regulation of B transport in plants towards minimizing B deficiency impacts on agriculture.
PMID: 31481193
BMC Plant Biol , IF:3.497 , 2019 Oct , V19 (1) : P443 doi: 10.1186/s12870-019-2054-x
Eriodictyol can modulate cellular auxin gradients to efficiently promote in vitro cotton fibre development.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University 430070, Wuhan, Hubei, People's Republic of China.; Institute of Plant Breeding & Biotechnology, MNS University of Agriculture, Multan, Pakistan.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University 430070, Wuhan, Hubei, People's Republic of China. lilitu@mail.hzau.edu.cn.
BACKGROUND: Flavonoids have essential roles in flower pigmentation, fibre development and disease resistance in cotton. Previous studies show that accumulation of naringenin in developing cotton fibres significantly affects fibre growth. This study focused on determining the effects of the flavonoids naringenin, dihydrokaempferol, dihydroquerectin and eriodictyol on fibre development in an in vitro system. RESULTS: 20 muM eriodictyol treatment produced a maximum fibre growth, in terms of fibre length and total fibre units. To gain insight into the associated transcriptional regulatory networks, RNA-seq analysis was performed on eriodictyol-treated elongated fibres, and computational analysis of differentially expressed genes revealed that carbohydrate metabolism and phytohormone signaling pathways were differentially modulated. Eriodictyol treatment also promoted the biosynthesis of quercetin and dihydroquerectin in ovules and elongating fibres through enhanced expression of genes encoding chalcone isomerase, chalcone synthase and flavanone 3-hydroxylase. In addition, auxin biosynthesis and signaling pathway genes were differentially expressed in eriodictyol-driven in vitro fibre elongation. In absence of auxin, eriodictyol predominantly enhanced fibre growth when the localized auxin gradient was disrupted by the auxin transport inhibitor, triiodobenzoic acid. CONCLUSION: Eriodictyol was found to significantly enhance fibre development through accumulating and maintaining the temporal auxin gradient in developing unicellular cotton fibres.
PMID: 31651240
BMC Plant Biol , IF:3.497 , 2019 Oct , V19 (1) : P435 doi: 10.1186/s12870-019-2002-9
Auxin regulates adventitious root formation in tomato cuttings.
Institute of Pomology, Jiangsu Academy of Agricultural Sciences / Jiangsu Key Laboratory for Horticultural Crop Genetic improvement, Nanjing, 210014, China.; Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, USA.; College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.; Department of Plant Sciences, University of Tennessee, Knoxville, TN, USA.; Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, USA. wapeer@umd.edu.; Department of Environmental Science and Technology, University of Maryland, College Park, MD, USA. wapeer@umd.edu.; Agriculture Biotechnology Center, University of Maryland, College Park, MD, USA. wapeer@umd.edu.; Agriculture Biotechnology Center, University of Maryland, College Park, MD, USA.
BACKGROUND: Adventitious root (AR) formation is a critical developmental process in cutting propagation for the horticultural industry. While auxin has been shown to regulate this process, the exact mechanism and details preceding AR formation remain unclear. Even though AR and lateral root (LR) formation share common developmental processes, there are exist some differences that need to be closely examined at the cytological level. Tomato stem cuttings, which readily form adventitious roots, represent the perfect system to study the influence of auxin on AR formation and to compare AR and LR organogenesis. RESULTS: Here we show the progression by which AR form from founder cells in the basal pericycle cell layers in tomato stem cuttings. The first disordered clumps of cells assumed a dome shape that later differentiated into functional AR cell layers. Further growth resulted in emergence of mature AR through the epidermis following programmed cell death of epidermal cells. Auxin and ethylene levels increased in the basal stem cutting within 1 h. Tomato lines expressing the auxin response element DR5pro:YFP showed an increase in auxin distribution during the AR initiation phase, and was mainly concentrated in the meristematic cells of the developing AR. Treatment of stem cuttings with auxin, increased the number of AR primordia and the length of AR, while stem cuttings treated with the pre-emergent herbicide/auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) occasionally developed thick, agravitropic AR. Hormone profile analyses showed that auxin positively regulated AR formation, whereas perturbations to zeatin, salicylic acid, and abscisic acid homeostasis suggested minor roles during tomato stem rooting. The gene expression of specific auxin transporters increased during specific developmental phases of AR formation. CONCLUSION: These data show that AR formation in tomato stems is a complex process. Upon perception of a wounding stimulus, expression of auxin transporter genes and accumulation of auxin at founder cell initiation sites in pericycle cell layers and later in the meristematic cells of the AR primordia were observed. A clear understanding and documentation of these events in tomato is critical to resolve AR formation in recalcitrant species like hardwoods and improve stem cutting propagation efficiency and effectiveness.
PMID: 31638898
BMC Plant Biol , IF:3.497 , 2019 Oct , V19 (1) : P415 doi: 10.1186/s12870-019-2011-8
Transcriptome analysis and identification of genes associated with fruiting branch internode elongation in upland cotton.
State Key Laboratory of Cotton Biology (Hebei Base)/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China.; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455112, Henan, China.; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455112, Henan, China. zhaoxinhua1968@126.com.; State Key Laboratory of Cotton Biology (Hebei Base)/College of Agronomy, Hebei Agricultural University, Baoding, 071001, Hebei, China. yongjiangzh@sina.com.; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455112, Henan, China. chypang@163.com.
BACKGROUND: Appropriate plant architecture can improve the amount of cotton boll opening and allow increased planting density, thus increasing the level of cotton mechanical harvesting and cotton yields. The internodes of cotton fruiting branches are an important part of cotton plant architecture. Thus, studying the molecular mechanism of internode elongation in cotton fruiting branches is highly important. RESULTS: In this study, we selected internodes of cotton fruiting branches at three different stages from two cultivars whose internode lengths differed significantly. A total of 76,331 genes were detected by transcriptome sequencing. By KEGG pathway analysis, we found that DEGs were significantly enriched in the plant hormone signal transduction pathway. The transcriptional data and qRT-PCR results showed that members of the GH3 gene family, which are involved in auxin signal transduction, and CKX enzymes, which can reduce the level of CKs, were highly expressed in the cultivar XLZ77, which has relatively short internodes. Genes related to ethylene synthase (ACS), EIN2/3 and ERF in the ethylene signal transduction pathway and genes related to JAR1, COI1 and MYC2 in the JA signal transduction pathway were also highly expressed in XLZ77. Plant hormone determination results showed that the IAA and CK contents significantly decreased in cultivar XLZ77 compared with those in cultivar L28, while the ACC (the precursor of ethylene) and JA contents significantly increased. GO enrichment analysis revealed that the GO categories associated with promoting cell elongation, such as cell division, the cell cycle process and cell wall organization, were significantly enriched, and related genes were highly expressed in L28. However, genes related to the sphingolipid metabolic process and lignin biosynthetic process, whose expression can affect cell elongation, were highly expressed in XLZ77. In addition, 2067 TFs were differentially expressed. The WRKY, ERF and bHLH TF families were the top three largest families whose members were active in the two varieties, and the expression levels of most of the genes encoding these TFs were upregulated in XLZ77. CONCLUSIONS: Auxin and CK are positive regulators of internode elongation in cotton branches. In contrast, ethylene and JA may act as negative regulators of internode elongation in cotton branches. Furthermore, the WRKY, ERF and bHLH TFs were identified as important inhibitors of internode elongation in cotton. In XLZ77(a short-internode variety), the mass synthesis of ethylene and amino acid conjugation of auxin led to the inhibition of plant cell elongation, while an increase in JA content and degradation of CKs led to a slow rate of cell division, which eventually resulted in a phenotype that presented relatively short internodes on the fruiting branches. The results of this study not only provide gene resources for the genetic improvement of cotton plant architecture but also lay a foundation for improved understanding of the molecular mechanism of the internode elongation of cotton branches.
PMID: 31590649
Planta , IF:3.39 , 2019 Oct , V250 (4) : P1177-1189 doi: 10.1007/s00425-019-03212-4
Mitogen-activated protein kinase 6 integrates phosphate and iron responses for indeterminate root growth in Arabidopsis thaliana.
CONACYT-Instituto de Investigaciones Quimico Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, CP 58030, Morelia, Michoacan, Mexico. jlopezb@conacyt.mx.; Instituto de Investigaciones Quimico Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, CP 58030, Morelia, Michoacan, Mexico.; Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, CP 62250, Cuernavaca, Morelos, Mexico.; Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, CP 62250, Cuernavaca, Morelos, Mexico. aguevara@ibt.unam.mx.
MAIN CONCLUSION: A MAPK module, of which MPK6 kinase is an important component, is involved in the coordination of the responses to Pi and Fe in the primary root meristem of Arabidopsis thaliana. Phosphate (Pi) deficiency induces determinate primary root growth in Arabidopsis through cessation of cell division in the meristem, which is linked to an increased iron (Fe) accumulation. Here, we show that Mitogen-Activated Protein Kinase6 (MPK6) has a role in Arabidopsis primary root growth under low Pi stress. MPK6 activity is induced in roots in response to low Pi, and such induction is enhanced by Fe supplementation, suggesting an MPK6 role in coordinating Pi/Fe balance in mediating root growth. The differentiation of the root meristem induced by low Pi levels correlates with altered expression of auxin-inducible genes and auxin transporter levels via MPK6. Our results indicate a critical role of the MPK6 kinase in coordinating meristem cell activity to Pi and Fe availability for proper primary root growth.
PMID: 31190117
ACS Omega , IF:2.87 , 2019 Oct , V4 (16) : P16789-16793 doi: 10.1021/acsomega.9b01550
Membrane-Protected Molecularly Imprinted Polymer for the Microextraction of Indole-3-butyric Acid in Mung Bean Sprouts.
College of Chemistry & Chemical Engineering, Xinjiang University, Key Laboratory of Oil and Gas Fine Chemical, Educational Ministry of China, Urumqi 830046, China.; The Key Laboratory of Plant Resources and Chemistry of Arid Zone, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China.
Based on the hollow fiber protected molecularly imprinted polymer, a micro-solid-phase extraction (mu-SPE) method was developed and applied for the analysis of indole-3-butyric acid in mung bean sprouts by high-performance liquid chromatography. The extraction conditions of the mu-SPE method were optimized using L(9)(3(4)) orthogonal, and optimum conditions were found as follows: pH of sample solution was 2.0, chloroform was the organic solvent for embedding the mu-SPE bars, and acetonitrile was the desorption solvent. In addition, the extraction time was 80 min, desorption time was 5 min, stirring speed was 800 rpm, and concentration of NaCl was 10%. Under the optimum conditions, a standard curve was established for IBA, with a correlation coefficient of 0.9999. After extraction with phosphate buffer solution (pH = 9.0), successful pretreatment of mung bean sprouts was achieved by the mu-SPE method. The limit of detection was 0.075 mg/kg, and the recoveries were found to be in the range of 88.9-106.4%. This method is simple, environmentally friendly, and can be used for the determination of indole auxin contents in green bean sprouts quickly and accurately.
PMID: 31646224
Plants (Basel) , IF:2.762 , 2019 Oct , V8 (10) doi: 10.3390/plants8100435
Potassium in Root Growth and Development.
Department of Experimental Plant Biology, Faculty of Science, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic. sustrm@natur.cuni.cz.; Department of Experimental Plant Biology, Faculty of Science, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic. asoukup@natur.cuni.cz.; Department of Experimental Plant Biology, Faculty of Science, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic. edmunz@natur.cuni.cz.
Potassium is an essential macronutrient that has been partly overshadowed in root science by nitrogen and phosphorus. The current boom in potassium-related studies coincides with an emerging awareness of its importance in plant growth, metabolic functions, stress tolerance, and efficient agriculture. In this review, we summarized recent progress in understanding the role of K(+) in root growth, development of root system architecture, cellular functions, and specific plant responses to K(+) shortage. K(+) transport is crucial for its physiological role. A wide range of K(+) transport proteins has developed during evolution and acquired specific functions in plants. There is evidence linking K(+) transport with cell expansion, membrane trafficking, auxin homeostasis, cell signaling, and phloem transport. This places K(+) among important general regulatory factors of root growth. K(+) is a rather mobile element in soil, so the absence of systemic and localized root growth response has been accepted. However, recent research confirms both systemic and localized growth response in Arabidopsis thaliana and highlights K(+) uptake as a crucial mechanism for plant stress response. K(+)-related regulatory mechanisms, K(+) transporters, K(+) acquisition efficiency, and phenotyping for selection of K(+) efficient plants/cultivars are highlighted in this review.
PMID: 31652570
Biometals , IF:2.479 , 2019 Oct , V32 (5) : P717-744 doi: 10.1007/s10534-019-00214-3
Reactive oxygen species, auxin and nitric oxide in metal-stressed roots: toxicity or defence.
Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dubravska cesta 9, 84523, Bratislava, Slovak Republic.; Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dubravska cesta 9, 84523, Bratislava, Slovak Republic. ladislav.tamas@savba.sk.
The presented review is a summary on the current knowledge about metal induced stress response in plants, focusing on the roles of reactive oxygen species, auxin and nitric oxide in roots. The article focuses mainly on the difference between defence and toxicity symptoms of roots during metal-induced stress. Nowadays, pollution of soils by heavy metals is a rapidly growing issue, which affects agriculture and human health. In order to deal with these problems, we must first understand the basic mechanisms and responses to environmental conditions in plants growing under such conditions. Studies so far show somewhat conflicting data, interpreting the same stress responses as both symptoms of defence and toxicity. Therefore, the aim of this review is to give a report about current knowledge of heavy metal-induced stress research, and also to differentiate between toxicity and defence, and outline the challenges of research, focusing on reactive oxygen and nitrogen species, auxin, and the interplay among them. There are still remaining questions on how reactive oxygen and nitrogen species, as well as auxin, can activate either symptoms of toxicity or defence, and adaptation responses.
PMID: 31541378
Biochem Genet , IF:2.027 , 2019 Oct , V57 (5) : P709-733 doi: 10.1007/s10528-019-09919-z
Genome-Wide Identification of the Aux/IAA Family Genes (MdIAA) and Functional Analysis of MdIAA18 for Apple Tree Ideotype.
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.
The Aux/IAA (auxin/indole-3-acetic acid) gene family is one of the early auxin-responsive gene families, which play a central role in auxin response. Few reports are involved in Aux/IAA genes in fruit trees, especially in apple (Malus x domestica Borkh.). A total of 33 MdIAA members were identified, of which 27 members contained four conserved domains, whereas the others lost one or two conserved domains. Several cis-elements in promoters of MdIAAs were predicted responsive to hormones and abiotic stress. Tissue-specific expression patterns of MdIAAs in different apple tree ideotypes were investigated by quantitative real-time PCR. A large number of MdIAAs were highly expressed in leaf buds and reproductive organs, and MdIAAs clustered in same group showed similar expression profiles. Overexpression of MdIAA18 in Arabidopsis resulted in compact phenotype. These results indicated that MdIAA genes may be involved in vegetative and reproductive growth of apple. Taken together, the results provide useful clues to reveal the function of MdIAAs in apple and control apple tree architecture by manipulation of MdIAAs.
PMID: 30997626
Mol Biol Rep , IF:1.402 , 2019 Oct , V46 (5) : P5295-5308 doi: 10.1007/s11033-019-04986-2
Metabolomic and transcriptomic profiling of three types of litchi pericarps reveals that changes in the hormone balance constitute the molecular basis of the fruit cracking susceptibility of Litchi chinensis cv. Baitangying.
College of Agro-forestry Engineering & Planning, Tongren University, Tongren, 554300, China. wangjugang@catas.cn.; South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Science, Zhanjiang, 524091, China. wangjugang@catas.cn.; Key Laboratory of Tropical Fruit Biology, Ministry of Agriculture, Zhanjiang, 524091, China. wangjugang@catas.cn.; Key Laboratory of Tropical Crops Nutrition, Zhanjiang, 524091, Hainan Province, China. wangjugang@catas.cn.; College of Agro-forestry Engineering & Planning, Tongren University, Tongren, 554300, China.; South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Science, Zhanjiang, 524091, China.; Key Laboratory of Tropical Fruit Biology, Ministry of Agriculture, Zhanjiang, 524091, China.; Key Laboratory of Tropical Crops Nutrition, Zhanjiang, 524091, Hainan Province, China.
Many Litchi chinensis cv. Baitangying orchards are suffering from a serious fruit cracking problem, but few studies have improved our understanding of the mechanism or the molecular basis of cracking susceptibility in 'Baitangying'. We conducted metabolome and transcriptome analyses of three types of litchi pericarps. To prevent passive progression after fruit cracking from affecting the results, we mainly focused on 11 metabolites and 101 genes that showed the same regulatory status and overlap in pairwise comparisons of cracking 'Baitangying' versus noncracking 'Baitangying' and noncracking 'Baitangying' versus noncracking 'Feizixiao'. Compared with the cracking-resistant cultivar 'Feizixiao', the 'Baitangying' pericarp has higher abscisic acid contents, and the presence of relevant metabolites and genes suggests increased biosynthesis of ethylene and jasmonic acid and decreased auxin and brassinosteroid biosynthesis. The fruit cracking-susceptible trait in 'Baitangying' might be associated with differences in the balance of these five types of hormones between the pericarp of this cultivar and that of 'Feizixiao'. Additionally, combined analyses showed a correspondence between the metabolite profiles and transcript patterns. qRT-PCR validation indicated the reliability of our high-throughput results. The acquired information might help in further studying the mechanisms that mediate fruit cracking susceptibility in 'Baitangying' and other litchi cultivars.
PMID: 31440876