Nat Plants , IF:13.256 , 2020 May , V6 (5) : P473-482 doi: 10.1038/s41477-020-0662-y
Design principles of a minimal auxin response system.
Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands.; Graduate School of Science, Kobe University, Kobe, Japan.; Graduate School of Biostudies, Kyoto University, Kyoto, Japan.; Alba Synchrotron, Cerdanyola del Valles, Barcelona, Spain.; Laboratory of Biophysics, Wageningen University, Wageningen, The Netherlands.; Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands. dolf.weijers@wur.nl.
Auxin controls numerous growth processes in land plants through a gene expression system that modulates ARF transcription factor activity(1-3). Gene duplications in families encoding auxin response components have generated tremendous complexity in most land plants, and neofunctionalization enabled various unique response outputs during development(1,3,4). However, it is unclear what fundamental biochemical principles underlie this complex response system. By studying the minimal system in Marchantia polymorpha, we derive an intuitive and simple model where a single auxin-dependent A-ARF activates gene expression. It is antagonized by an auxin-independent B-ARF that represses common target genes. The expression patterns of both ARF proteins define developmental zones where auxin response is permitted, quantitatively tuned or prevented. This fundamental design probably represents the ancestral system and formed the basis for inflated, complex systems.
PMID: 32415296
Nat Plants , IF:13.256 , 2020 May , V6 (5) : P440-441 doi: 10.1038/s41477-020-0668-5
Barebones of auxin signalling.
Section of Cell and Developmental Biology, University of California, San Diego, San Diego, La Jolla, CA, USA.; Section of Cell and Developmental Biology, University of California, San Diego, San Diego, La Jolla, CA, USA. mestelle@ucsd.edu.
PMID: 32415293
Nat Plants , IF:13.256 , 2020 May , V6 (5) : P556-569 doi: 10.1038/s41477-020-0648-9
The lipid code-dependent phosphoswitch PDK1-D6PK activates PIN-mediated auxin efflux in Arabidopsis.
Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria.; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria.; National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.; Institute of Experimental Botany, The Czech Academy of Sciences, Prague, Czech Republic.; Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria. jiri.friml@ist.ac.at.; National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China. hwxue@sjtu.edu.cn.; Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China. hwxue@sjtu.edu.cn.
Directional intercellular transport of the phytohormone auxin mediated by PIN-FORMED (PIN) efflux carriers has essential roles in both coordinating patterning processes and integrating multiple external cues by rapidly redirecting auxin fluxes. PIN activity is therefore regulated by multiple internal and external cues, for which the underlying molecular mechanisms are not fully elucidated. Here, we demonstrate that 3'-PHOSPHOINOSITIDE-DEPENDENT PROTEIN KINASE1 (PDK1), which is conserved in plants and mammals, functions as a molecular hub that perceives upstream lipid signalling and modulates downstream substrate activity through phosphorylation. Using genetic analysis, we show that the loss-of-function Arabidopsis pdk1.1 pdk1.2 mutant exhibits a plethora of abnormalities in organogenesis and growth due to defective polar auxin transport. Further cellular and biochemical analyses reveal that PDK1 phosphorylates D6 protein kinase, a well-known upstream activator of PIN proteins. We uncover a lipid-dependent phosphorylation cascade that connects membrane-composition-based cellular signalling with plant growth and patterning by regulating morphogenetic auxin fluxes.
PMID: 32393881
Nat Plants , IF:13.256 , 2020 May , V6 (5) : P544-555 doi: 10.1038/s41477-020-0650-2
PDK1 regulates auxin transport and Arabidopsis vascular development through AGC1 kinase PAX.
Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, Leiden, the Netherlands.; Plant Systems Biology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.; Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, Leiden, the Netherlands. r.offringa@biology.leidenuniv.nl.
The 3-phosphoinositide-dependent protein kinase 1 (PDK1) is a conserved master regulator of AGC kinases in eukaryotic organisms. pdk1 loss of function causes a lethal phenotype in animals and yeasts, but only mild phenotypic defects in Arabidopsis thaliana (Arabidopsis). The Arabidopsis genome contains two PDK1-encoding genes, PDK1 and PDK2. Here, we used clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) to generate true loss-of-function pdk1 alleles, which, when combined with pdk2 alleles, showed severe developmental defects including fused cotyledons, a short primary root, dwarf stature and defects in male fertility. We obtained evidence that PDK1 is responsible for AGC1 kinase PROTEIN KINASE ASSOCIATED WITH BRX (PAX) activation by phosphorylation during vascular development, and that the PDK1 phospholipid-binding Pleckstrin Homology domain is not required for this process. Our data indicate that PDK1 regulates polar auxin transport by activating AGC1 clade kinases, resulting in PIN phosphorylation.
PMID: 32393878
Nat Plants , IF:13.256 , 2020 May , V6 (5) : P522-532 doi: 10.1038/s41477-020-0633-3
An RNA thermoswitch regulates daytime growth in Arabidopsis.
Department of Plant Sciences, University of Cambridge, Cambridge, UK. bcy23@cam.ac.uk.; Department of Pathology, University of Cambridge, Cambridge, UK. bcy23@cam.ac.uk.; Sainsbury Laboratory, University of Cambridge, Cambridge, UK.; Department of Chemistry, Molecular Science Research Hub, Imperial College London, London, UK.; Leibniz-Institut fur Gemuse- und Zierpflanzenbau, Grossbeeren, Germany.; Department of Pathology, University of Cambridge, Cambridge, UK.; Department of Plant Sciences, University of Cambridge, Cambridge, UK. wigge@igzev.de.; Sainsbury Laboratory, University of Cambridge, Cambridge, UK. wigge@igzev.de.; Leibniz-Institut fur Gemuse- und Zierpflanzenbau, Grossbeeren, Germany. wigge@igzev.de.; Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany. wigge@igzev.de.
Temperature is a major environmental cue affecting plant growth and development. Plants often experience higher temperatures in the context of a 24 h day-night cycle, with temperatures peaking in the middle of the day. Here, we find that the transcript encoding the bHLH transcription factor PIF7 undergoes a direct increase in translation in response to warmer temperature. Diurnal expression of PIF7 transcript gates this response, allowing PIF7 protein to quickly accumulate in response to warm daytime temperature. Enhanced PIF7 protein levels directly activate the thermomorphogenesis pathway by inducing the transcription of key genes such as the auxin biosynthetic gene YUCCA8, and are necessary for thermomorphogenesis to occur under warm cycling daytime temperatures. The temperature-dependent translational enhancement of PIF7 messenger RNA is mediated by the formation of an RNA hairpin within its 5' untranslated region, which adopts an alternative conformation at higher temperature, leading to increased protein synthesis. We identified similar hairpin sequences that control translation in additional transcripts including WRKY22 and the key heat shock regulator HSFA2, suggesting that this is a conserved mechanism enabling plants to respond and adapt rapidly to high temperatures.
PMID: 32284544
Nat Commun , IF:12.121 , 2020 May , V11 (1) : P2629 doi: 10.1038/s41467-020-16403-5
UDP-glucosyltransferase regulates grain size and abiotic stress tolerance associated with metabolic flux redirection in rice.
National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences and Collaborative Innovation Center of Genetics & Development, Shanghai Institute of Plant Physiology & Ecology, Chinese Academic of Sciences, Shanghai, 200032, China.; CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology & Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.; University of the Chinese Academy of Sciences, 100049, Beijing, China.; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.; National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences and Collaborative Innovation Center of Genetics & Development, Shanghai Institute of Plant Physiology & Ecology, Chinese Academic of Sciences, Shanghai, 200032, China. wwye@sibs.ac.cn.; National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences and Collaborative Innovation Center of Genetics & Development, Shanghai Institute of Plant Physiology & Ecology, Chinese Academic of Sciences, Shanghai, 200032, China. jxshan@cemps.ac.cn.; National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences and Collaborative Innovation Center of Genetics & Development, Shanghai Institute of Plant Physiology & Ecology, Chinese Academic of Sciences, Shanghai, 200032, China. hxlin@sibs.ac.cn.; University of the Chinese Academy of Sciences, 100049, Beijing, China. hxlin@sibs.ac.cn.; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China. hxlin@sibs.ac.cn.
Grain size is an important component trait of grain yield, which is frequently threatened by abiotic stress. However, little is known about how grain yield and abiotic stress tolerance are regulated. Here, we characterize GSA1, a quantitative trait locus (QTL) regulating grain size and abiotic stress tolerance associated with metabolic flux redirection. GSA1 encodes a UDP-glucosyltransferase, which exhibits glucosyltransferase activity toward flavonoids and monolignols. GSA1 regulates grain size by modulating cell proliferation and expansion, which are regulated by flavonoid-mediated auxin levels and related gene expression. GSA1 is required for the redirection of metabolic flux from lignin biosynthesis to flavonoid biosynthesis under abiotic stress and the accumulation of flavonoid glycosides, which protect rice against abiotic stress. GSA1 overexpression results in larger grains and enhanced abiotic stress tolerance. Our findings provide insights into the regulation of grain size and abiotic stress tolerance associated with metabolic flux redirection and a potential means to improve crops.
PMID: 32457405
Nat Commun , IF:12.121 , 2020 May , V11 (1) : P2277 doi: 10.1038/s41467-020-16147-2
Flexibility of intrinsically disordered degrons in AUX/IAA proteins reinforces auxin co-receptor assemblies.
Molecular Signal Processing Department, Leibniz Institute of Plant Biochemistry (IPB), Weinberg 3, 06120, Halle (Saale), Germany.; Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Strasse 3a, 06120, Halle (Saale), Germany.; Proteome Analytics, Leibniz Institute of Plant Biochemistry (IPB), Weinberg 3, 06120, Halle (Saale), Germany.; Institute of Synthetic Biology & Cluster of Excellence on Plant Science (CEPLAS), Heinrich-Heine University of Dusseldorf, Universitatsstrasse 1, 40225, Dusseldorf, Germany.; ZIK HALOMEM & Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Biozentrum, Weinbergweg 22, 06120, Halle (Saale), Germany.; Molecular Signal Processing Department, Leibniz Institute of Plant Biochemistry (IPB), Weinberg 3, 06120, Halle (Saale), Germany. LuzIrina.Calderon@ipb-halle.de.
Cullin RING-type E3 ubiquitin ligases SCF(TIR1/AFB1-5) and their AUX/IAA targets perceive the phytohormone auxin. The F-box protein TIR1 binds a surface-exposed degron in AUX/IAAs promoting their ubiquitylation and rapid auxin-regulated proteasomal degradation. Here, by adopting biochemical, structural proteomics and in vivo approaches we unveil how flexibility in AUX/IAAs and regions in TIR1 affect their conformational ensemble allowing surface accessibility of degrons. We resolve TIR1.auxin.IAA7 and TIR1.auxin.IAA12 complex topology, and show that flexible intrinsically disordered regions (IDRs) in the degron's vicinity, cooperatively position AUX/IAAs on TIR1. We identify essential residues at the TIR1 N- and C-termini, which provide non-native interaction interfaces with IDRs and the folded PB1 domain of AUX/IAAs. We thereby establish a role for IDRs in modulating auxin receptor assemblies. By securing AUX/IAAs on two opposite surfaces of TIR1, IDR diversity supports locally tailored positioning for targeted ubiquitylation, and might provide conformational flexibility for a multiplicity of functional states.
PMID: 32385295
Nat Commun , IF:12.121 , 2020 May , V11 (1) : P2143 doi: 10.1038/s41467-020-16068-0
A common allosteric mechanism regulates homeostatic inactivation of auxin and gibberellin.
Bioscience and Biotechnology Centre, Nagoya University, Nagoya, 464-8601, Japan.; Molecular Modelling and Simulation Group, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Japan.; Division of Applied Life Sciences, The Graduate School of Agriculture, Kyoto University, Uji, 611-0011, Japan.; Plant Genome Engineering Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, 305-8602, Japan.; Synchrotron Radiation Research Centre, Nagoya University, Nagoya, 464-8601, Japan.; Bioscience and Biotechnology Centre, Nagoya University, Nagoya, 464-8601, Japan. mueguchi@nuagr1.agr.nagoya-u.ac.jp.
Allosteric regulation is protein activation by effector binding at a site other than the active site. Here, we show via X-ray structural analysis of gibberellin 2-oxidase 3 (GA2ox3), and auxin dioxygenase (DAO), that such a mechanism maintains hormonal homeostasis in plants. Both enzymes form multimers by interacting via GA4 and indole-3-acetic acid (IAA) at their binding interface. Via further functional analyses we reveal that multimerization of these enzymes gradually proceeds with increasing GA4 and IAA concentrations; multimerized enzymes have higher specific activities than monomer forms, a system that should favour the maintenance of homeostasis for these phytohormones. Molecular dynamic analysis suggests a possible mechanism underlying increased GA2ox3 activity by multimerization-GA4 in the interface of oligomerized GA2ox3s may be able to enter the active site with a low energy barrier. In summary, homeostatic systems for maintaining GA and IAA levels, based on a common allosteric mechanism, appear to have developed independently.
PMID: 32358569
Nat Commun , IF:12.121 , 2020 May , V11 (1) : P2170 doi: 10.1038/s41467-020-15895-5
SYNERGISTIC ON AUXIN AND CYTOKININ 1 positively regulates growth and attenuates soil pathogen resistance.
Institute of Science and Technology, Klosterneuburg, Austria.; Departamento de Biologia de Organismos y Sistemas, Universidad de Oviedo, Oviedo, Spain.; Bioresources Unit, Center for Health & Bioresources, AIT Austrian Institute of Technology, Tulln, Austria.; Unite 'Ecologie et Dynamique des Systemes Anthropises' (EDYSAN UMR CNRS 7058 CNRS), Universite du Picardie Jules Verne, UFR des Sciences, Amiens, France.; Institute of Biophysics, The Czech Academy of Sciences, Kralovopolska 135, 61265, Brno, Czech Republic.; Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno, Czech Republic.; Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstrasse 6/6, 8010, Graz, Austria.; Department of Cellular Biochemistry, Institute for Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Halle, Germany.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.; VIB Center for Plant Systems Biology, Ghent, Belgium.; Institut fur Botanik, Technische Universitat Dresden, Dresden, Germany.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83, Umea, Sweden.; Department of Chemistry, Umea University, Linnaeus vag 6, SE-901 87, Umea, Sweden.; Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Universite Paris-Saclay, 78000, Versailles, France.; Institute of Science and Technology, Klosterneuburg, Austria. eva.benkova@ist.ac.at.
Plants as non-mobile organisms constantly integrate varying environmental signals to flexibly adapt their growth and development. Local fluctuations in water and nutrient availability, sudden changes in temperature or other abiotic and biotic stresses can trigger changes in the growth of plant organs. Multiple mutually interconnected hormonal signaling cascades act as essential endogenous translators of these exogenous signals in the adaptive responses of plants. Although the molecular backbones of hormone transduction pathways have been identified, the mechanisms underlying their interactions are largely unknown. Here, using genome wide transcriptome profiling we identify an auxin and cytokinin cross-talk component; SYNERGISTIC ON AUXIN AND CYTOKININ 1 (SYAC1), whose expression in roots is strictly dependent on both of these hormonal pathways. We show that SYAC1 is a regulator of secretory pathway, whose enhanced activity interferes with deposition of cell wall components and can fine-tune organ growth and sensitivity to soil pathogens.
PMID: 32358503
Mol Plant , IF:12.084 , 2020 May , V13 (5) : P777-792 doi: 10.1016/j.molp.2020.02.015
Coordinated Transcriptional Regulation by the UV-B Photoreceptor and Multiple Transcription Factors for Plant UV-B Responses.
State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China.; State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China. Electronic address: xihuang@xmu.edu.cn.
Non-damaging ultraviolet B (UV-B) light promotes photomorphogenic development and stress acclimation through UV-B-specific signal transduction in Arabidopsis. UV-B irradiation induces monomerization and nuclear translocation of the UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8). However, it is not clear how the nuclear localization of UVR8 leads to changes in global gene expression. Here, we reveal that nuclear UVR8 governs UV-B-responsive transcriptional networks in concert with several previously known transcription factors, including ELONGATED HYPOCOTYL 5 (HY5) and PHYTOCHROME INTERACTING FACTOR 4 (PIF4). Based on the transcriptomic analysis, we identify MYB13 as a novel positive regulator in UV-B-induced cotyledon expansion and stress acclimation. MYB13 is UV-B inducible and is predominantly expressed in the cotyledons. Our results demonstrate that MYB13 protein functions as a transcription factor to regulate the expression of genes involved in auxin response and flavonoid biosynthesis through direct binding with their promoters. In addition, photoactivated UVR8 interacts with MYB13 in a UV-B-dependent manner and differentially modulates the affinity of MYB13 with its targets. Taken together, our results elucidate the cooperative function of the UV-B photoreceptor UVR8 with various transcription factors in the nucleus to orchestrate the expression of specific sets of downstream genes and, ultimately, mediate plant responses to UV-B light.
PMID: 32126287
Mol Biol Evol , IF:11.062 , 2020 May , V37 (5) : P1387-1393 doi: 10.1093/molbev/msz202
Molecular Evolution of Auxin-Mediated Root Initiation in Plants.
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.; University of Chinese Academy of Sciences, Beijing, China.; College of Life and Environment Sciences, Shanghai Normal University, Shanghai, China.
The root originated independently in euphyllophytes (ferns and seed plants) and lycophytes; however, the molecular evolutionary route of root initiation remains elusive. By analyses of the fern Ceratopteris richardii and seed plants, here we show that the molecular pathway involving auxin, intermediate-clade WUSCHEL-RELATED HOMEOBOX (IC-WOX) genes, and WUSCHEL-clade WOX (WC-WOX) genes could be conserved in root initiation. We propose that the "auxin>IC-WOX>WC-WOX" module in root initiation might have arisen in the common ancestor of euphyllophytes during the second origin of roots, and that this module has further developed during the evolution of different root types in ferns and seed plants.
PMID: 31504735
Plant Cell , IF:9.618 , 2020 May doi: 10.1105/tpc.19.00022
The Type-B Cytokinin Response Regulator ARR1 Inhibits Shoot Regeneration in an ARR12-Dependent Manner in Arabidopsis.
Shandong University CITY: Jinan China [CN].; Shandong University CITY: Jinan STATE: Shandong China [CN].; Shandong University CITY: Qingdao China [CN] xfn0990@sdu.edu.cn.
Exogenous cytokinin is critical for in vitro shoot regeneration. Proteins involved in the cytokinin signal transduction pathway, including type-B ARABIDOPSIS RESPONSE REGULATORs (ARRs), participate in shoot regeneration in Arabidopsis thaliana. Some type-B ARRs (e.g., ARR1 and ARR12) promote shoot regeneration by directly activating WUSCHEL (WUS) expression; however, it is unclear how type-B ARRs inhibit shoot regeneration. Here, we show that ARR12 is a central enhancer of callus formation and shoot regeneration, whereas ARR1 is a strong inhibitor of this process that counteracts the positive effect of ARR12. ARR1 indirectly represses CLAVATA3 expression in an ARR12-dependent manner via competing with ARR12 for binding to the CLV3 promoter, which contributes to its ARR12-dependent inhibitory effect on callus formation and shoot regeneration. In parallel, ARR1 inhibits shoot regeneration through transcriptional activation of INDOLE-3-ACETIC ACID INDUCIBLE17 (IAA17), an auxin response repressor gene, and the consequent indirect repression of WUS expression. Thus, type-B ARRs have diverse effects on callus formation and shoot regeneration. Our study reveals novel molecular pathways linking cytokinin signaling, the CLV3 regulator, and auxin signaling, and sheds light on the mechanism underlying cytokinin-regulated shoot regeneration.
PMID: 32398274
Plant Cell , IF:9.618 , 2020 May doi: 10.1105/tpc.20.00044
TRIPP is a Plant-specific Component of the Arabidopsis TRAPPII Membrane Trafficking Complex with Important Roles in Plant Development.
Carnegie Institution for Science CITY: Stanford STATE: CA POSTAL_CODE: 94305 United States Of America [US].; University of Stanford CITY: Stanford United States Of America [US].; Plant Science Department, Botany, Technische Universitat Munchen, 85354 Freising, Germany CITY: Munich Germany [DE].; Fujian Agriculture and Forestry University (FAFU) CITY: Fuzhou STATE: Fujian POSTAL_CODE: 350002 China [CN].; Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK CITY: Oxford POSTAL_CODE: OX1 3RB United Kingdom [GB].; Department of Plant Biology, Carnegie Institution for Science CITY: Stanford STATE: CA United States Of America [US].; Department of Plant Sciences, University of Oxford CITY: Oxford United Kingdom [GB].; Institute of Network Biology (INET), Helmholtz Zentrum Munchen, Deutsches Forschungszentrum fur Gesundheit und Umwelt (GmbH), 85764 Neuherberg, Germany CITY: Munich Germany [DE].; Plant Science Department, Botany, Technische Universitat Munchen CITY: Munich Germany [DE].; German Research Center for Environmental Health CITY: Neuherberg Germany [DE].; Oxford University CITY: Oxford OX1 3RB United Kingdom [GB].; University of California CITY: San Francisco STATE: CA United States Of America [US].; Botany Department Center for Life Sciences , Weihenstephan, Technische Universitat Munchen CITY: Freising Germany [DE].; Department of Plant Biology, Carnegie Institution for Science CITY: Stanford STATE: California POSTAL_CODE: 94305 United States Of America [US] zywang24@stanford.edu.
How the membrane trafficking system spatially organizes intracellular activities and intercellular signaling networks is not well understood in plants. The TRAnsport Protein Particle (TRAPP) complexes play key roles in selective delivery of membrane vesicles to various subcellular compartments in yeast and animals, but are not characterized in plants. Here we interrogate TRAPP complexes in Arabidopsis. Affinity purification of a core subunit AtTRS33 followed by quantitative mass spectrometry identified fourteen interacting proteins; including homologues of all thirteen TRAPP components in yeast and mammals and a novel protein we named TRAPP-interacting plant protein (TRIPP), which is conserved in multi-cellular photosynthetic organisms. Proteomic and molecular analyses showed that TRIPP specifically associates with the TRAPPII complex through binary interactions with two TRAPPII-specific subunits. TRIPP co-localizes with a subset of TRS33 compartments and trans-Golgi network markers in a TRS33-dependent manner. Loss-of-function tripp mutation caused dwarfism, sterility, partial photomorphogenesis in the dark, reduced polarity of the auxin transporter PIN2, incomplete cross wall formation and altered localization of a TRAPPII-specific component. Our study demonstrates that plants possess at least two distinct TRAPP complexes similar to metazoans, and identifies TRIPP as a novel plant-specific component of the TRAPPII complex with important functions in trafficking, plant growth and development.
PMID: 32371545
Plant Cell , IF:9.618 , 2020 May , V32 (5) : P1644-1664 doi: 10.1105/tpc.19.00869
Arabidopsis Flippases Cooperate with ARF GTPase Exchange Factors to Regulate the Trafficking and Polarity of PIN Auxin Transporters.
Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190, Vienna, Austria.; Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland.; Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno CZ-625 00, Czech Republic.; Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria jiri.friml@ist.ac.at.
Cell polarity is a fundamental feature of all multicellular organisms. PIN auxin transporters are important cell polarity markers that play crucial roles in a plethora of developmental processes in plants. Here, to identify components involved in cell polarity establishment and maintenance in plants, we performed a forward genetic screening of PIN2:PIN1-HA;pin2 Arabidopsis (Arabidopsis thaliana) plants, which ectopically express predominantly basally localized PIN1 in root epidermal cells, leading to agravitropic root growth. We identified the regulator of PIN polarity 12 (repp12) mutation, which restored gravitropic root growth and caused a switch in PIN1-HA polarity from the basal to apical side of root epidermal cells. Next Generation Sequencing and complementation experiments established the causative mutation of repp12 as a single amino acid exchange in Aminophospholipid ATPase3 (ALA3), a phospholipid flippase predicted to function in vesicle formation. repp12 and ala3 T-DNA mutants show defects in many auxin-regulated processes, asymmetric auxin distribution, and PIN trafficking. Analysis of quintuple and sextuple mutants confirmed the crucial roles of ALA proteins in regulating plant development as well as PIN trafficking and polarity. Genetic and physical interaction studies revealed that ALA3 functions together with the ADP ribosylation factor GTPase exchange factors GNOM and BIG3 in regulating PIN polarity, trafficking, and auxin-mediated development.
PMID: 32193204
Curr Biol , IF:9.601 , 2020 May , V30 (9) : PR407-R409 doi: 10.1016/j.cub.2020.02.073
Plant Biology: Brassinosteroids and the Intracellular Auxin Shuttle.
Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland.; Department of Plant Molecular Biology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland. Electronic address: christian.hardtke@unil.ch.
Throughout plant development, the phytohormones auxin and brassinosteroid regulate growth via their combinatorial input. A new study reveals a major impact of brassinosteroid signaling on intracellular auxin distribution and thereby nuclear auxin signaling, adding another layer of complexity to auxin-brassinosteroid crosstalk.
PMID: 32369755
Curr Biol , IF:9.601 , 2020 May , V30 (10) : P1970-1977.e4 doi: 10.1016/j.cub.2020.03.014
Directionality of Plasmodesmata-Mediated Transport in Arabidopsis Leaves Supports Auxin Channeling.
College of Life Sciences, Northwest A&F University, Taicheng Road 3, 712100 Yangling, China; Biomass Energy Center for Arid Lands, Northwest A&F University, Taicheng Road 3, 712100 Yangling, China.; College of Agriculture, South China Agricultural University, Wushan Road 483, 510642 Guangzhou, China.; Department of Biosystems, KU Leuven, Willem de Croylaan 42, 3001 Heverlee, Belgium.; Department of Physics, Technical University of Denmark, Fysikvej, 2800 Kongens Lyngby, Denmark.; Department of Geosciences, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.; Department of Plant and Environmental Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.; College of Life Sciences, Northwest A&F University, Taicheng Road 3, 712100 Yangling, China; Biomass Energy Center for Arid Lands, Northwest A&F University, Taicheng Road 3, 712100 Yangling, China. Electronic address: liesche@nwafu.edu.cn.
The plant hormone auxin serves as central regulator of growth and development. Auxin transporters in the plasma membrane are assumed to define tissue-level patterns of auxin distribution [1, 2]. However, auxin is small enough to diffuse through the plasmodesmata that connect neighboring cells [3], presenting an alternative pathway, whose contribution to auxin transport remained largely unexplored [4]. Here, photoactivation microscopy [5, 6] was used to measure the capacity for small-molecule diffusion in the epidermis of Arabidopsis thaliana leaves. In the elongated epidermis cells covering the midrib and petiole, the plasmodesmata-mediated cell-wall permeability was found to be several times higher in the longitudinal than in the transverse direction. The physiological relevance of this asymmetry was tested through quantification of the shade-avoidance response, which depends on auxin transport from the leaf tip to the petiole in the abaxial side of the leaf [7], with the hypothesis that directionality of diffusion supplements transporter-mediated auxin movement [8]. Triggering the response by auxin application at the tip led to stronger leaf movement in wild-type plants than in gsl8 mutants [9], which lack the callose synthase necessary to establish directionality. The results match the predictions of a mathematical model of auxin transport based on the permeabilities measured in wild-type and mutant plants. It is concluded that plasmodesmata permeability can be selectively modulated within a plant cell and that the conferred directionality in diffusion can influence the tissue-specific distribution patterns of small molecules, like auxin. VIDEO ABSTRACT.
PMID: 32275878
Curr Biol , IF:9.601 , 2020 May , V30 (9) : P1733-1739.e3 doi: 10.1016/j.cub.2020.02.055
Interplay between Cell Wall and Auxin Mediates the Control of Differential Cell Elongation during Apical Hook Development.
Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 10083, China; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umea 901 87, Sweden.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umea 901 87, Sweden.; Department of Biology, ETH Zurich, Zurich 8092, Switzerland.; Plant Biology Research Institute, University of Montreal, Montreal, QC H1X 2B2, Canada.; Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 10083, China; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umea 901 87, Sweden. Electronic address: rishi.bhalerao@slu.se.
Differential growth plays a crucial role during morphogenesis [1-3]. In plants, development occurs within mechanically connected tissues, and local differences in cell expansion lead to deformations at the organ level, such as buckling or bending [4, 5]. During early seedling development, bending of hypocotyl by differential cell elongation results in apical hook structure that protects the shoot apical meristem from being damaged during emergence from the soil [6, 7]. Plant hormones participate in apical hook development, but not how they mechanistically drive differential growth [8]. Here, we present evidence of interplay between hormonal signals and cell wall in auxin-mediated differential cell elongation using apical hook development as an experimental model. Using genetic and cell biological approaches, we show that xyloglucan (a major primary cell wall component) mediates asymmetric mechanical properties of epidermal cells required for hook development. The xxt1 xxt2 mutant, deficient in xyloglucan [9], displays severe defects in differential cell elongation and hook development. Analysis of xxt1 xxt2 mutant reveals a link between cell wall and transcriptional control of auxin transporters PINFORMEDs (PINs) and AUX1 crucial for establishing the auxin response maxima required for preferential repression of elongation of the cells on the inner side of the hook. Genetic evidence identifies auxin response factor ARF2 as a negative regulator acting downstream of xyloglucan-dependent control of hook development and transcriptional control of polar auxin transport. Our results reveal a crucial feedback process between the cell wall and transcriptional control of polar auxin transport, underlying auxin-dependent control of differential cell elongation in plants.
PMID: 32197084
Curr Biol , IF:9.601 , 2020 May , V30 (9) : P1579-1588.e6 doi: 10.1016/j.cub.2020.02.002
PIN-LIKES Coordinate Brassinosteroid Signaling with Nuclear Auxin Input in Arabidopsis thaliana.
Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Muthgasse 18, Vienna 1190, Austria.; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA; Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University (FAFU), Fuzhou 350002, China.; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA.; Centro de Biotecnologia y Genomica de Plantas (CBGP, UPM-INIA) Universidad Politecnica de Madrid (UPM) - Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), Campus de Montegancedo-UPM, 28223 Pozuelo de Alarcon, Madrid, Spain.; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), Muthgasse 18, Vienna 1190, Austria. Electronic address: juergen.kleine-vehn@boku.ac.at.
Auxin and brassinosteroids (BR) are crucial growth regulators and display overlapping functions during plant development. Here, we reveal an alternative phytohormone crosstalk mechanism, revealing that BR signaling controls PIN-LIKES (PILS)-dependent nuclear abundance of auxin. We performed a forward genetic screen for imperial pils (imp) mutants that enhance the overexpression phenotypes of PILS5 putative intracellular auxin transport facilitator. Here, we report that the imp1 mutant is defective in the BR-receptor BRASSINOSTEROID INSENSITIVE 1 (BRI1). Our set of data reveals that BR signaling transcriptionally and post-translationally represses the accumulation of PILS proteins at the endoplasmic reticulum, thereby increasing nuclear abundance and signaling of auxin. We demonstrate that this alternative phytohormonal crosstalk mechanism integrates BR signaling into auxin-dependent organ growth rates and likely has widespread importance for plant development.
PMID: 32169207
New Phytol , IF:8.512 , 2020 May doi: 10.1111/nph.16707
Transfer cells: What regulates the development of their intricate wall labyrinths?
School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia.
Transfer cells (TCs) support high nutrient rates into, or at symplasmic discontinuities within, the plant body. Their transport capacity is conferred by an amplified plasma membrane surface area, enriched in nutrient transporters, supported on an intricately-invaginated wall labyrinth (WL). Thus, development of the WL is at the heart of TC function. Enquiry has shifted from describing WL architecture and formation, to discovering mechanisms regulating WL assembly. Experimental systems used to examine these phenomena are critiqued. Considerable progress has been made in identifying master regulators that commit stem cells to a TC fate (e.g., the maize Myeloblastosis (MYB)-related R1-type transcription factor) and signals that induce differentiated cells to undergo trans-differentiation to a TC phenotype (e.g., sugar, auxin and ethylene). In addition, signals that provide positional information for assembly of the WL include apoplasmic hydrogen peroxide and cytosolic Ca(2+) plumes. The former switches on, and specifies the intracellular site for WL construction, while the latter creates sub-domains to direct assembly of WL invaginations. Less is known about macromolecule species and their spatial organization essential for WL assembly. Emerging evidence points to a dependency on methyl-esterified homogalacturonan accumulation, unique patterns of cellulose and callose deposition and spatial positioning of arabinogalactan proteins.
PMID: 32463520
Curr Opin Plant Biol , IF:8.356 , 2020 May , V57 : P1-7 doi: 10.1016/j.pbi.2020.04.008
It's Morphin' time: how multiple signals converge on ARF transcription factors to direct development.
Department of Biology, University of Washington, Seattle, WA 98195, United States; Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, United States.; Department of Biology, University of Washington, Seattle, WA 98195, United States. Electronic address: jn7@uw.edu.
Plant development programs are constantly updated by information about environmental conditions, currently available resources, and sites of active organogenesis. Much of this information is encoded in modifications of transcription factors that lead to changes in their relative abundance, activity and localization. Recent work on the Auxin Response Factor family of transcription factors has highlighted the large diversity of such modifications, as well as how they may work synergistically or antagonistically to regulate downstream responses. ARFs can be regulated by alternative splicing, post-translational modification, and subcellular localization, among many other mechanisms. Beyond the many ways ARFs themselves can be regulated, they can also act cooperatively with other transcription factors to enable highly complex genetic networks with distinct developmental outcomes. Multi-level regulation like what has been documented for ARFs has the capacity to generate flexibility in transcriptional outputs, as well as resilience to short-term perturbations.
PMID: 32480312
Plant Biotechnol J , IF:8.154 , 2020 May doi: 10.1111/pbi.13392
Maize BIG GRAIN1 homolog overexpression increases maize grain yield.
Corteva Agriscience, Johnston, IA, USA.
The Zea Mays BIG GRAIN 1 HOMOLOG 1 (ZM-BG1H1) was ectopically expressed in maize. Elite commercial hybrid germplasm was yield tested in diverse field environment locations representing commercial models. Yield was measured in 101 tests across all 4 events, 26 locations over 2 years, for an average yield gain of 355 kg/ha (5.65 bu/ac) above control, with 83% tests broadly showing yield gains (range +2272 kg/ha to -1240 kg/ha), with seven tests gaining more than one metric ton per hectare. Plant and ear height were slightly elevated, and ear and tassel flowering time were delayed one day, but ASI was unchanged, and these traits did not correlate to yield gain. ZM-BG1H1 overexpression is associated with increased ear kernel row number and total ear kernel number and mass, but individual kernels trended slightly smaller and less dense. The ZM-BG1H1 protein is detected in the plasma membrane like rice OS-BG1. Five predominant native ZM-BG1H1 alleles exhibit little structural and expression variation compared to the large increased expression conferred by these ectopic alleles.
PMID: 32356392
Plant Biotechnol J , IF:8.154 , 2020 May , V18 (5) : P1141-1152 doi: 10.1111/pbi.13279
Rice microtubule-associated protein IQ67-DOMAIN14 regulates grain shape by modulating microtubule cytoskeleton dynamics.
National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.; VIB Center for Plant Systems Biology, Ghent, Belgium.; Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands.; School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.
Cortical microtubule (MT) arrays play a critical role in plant cell shape determination by defining the direction of cell expansion. As plants continuously adapt to ever-changing environmental conditions, multiple environmental and developmental inputs need to be translated into changes of the MT cytoskeleton. Here, we identify and functionally characterize an auxin-inducible and MT-localized protein OsIQ67-DOMAIN14 (OsIQD14), which is highly expressed in rice seed hull cells. We show that while deficiency of OsIQD14 results in short and wide seeds and increases overall yield, overexpression leads to narrow and long seeds, caused by changed MT alignment. We further show that OsIQD14-mediated MT reordering is regulated by specifically affecting MT dynamics, and ectopic expression of OsIQD14 in Arabidopsis could change the cell shape both in pavement cells and in hypocotyl cells. Additionally, OsIQD14 activity is tightly controlled by calmodulin proteins, providing an alternative way to modify the OsIQD14 activity. Our results indicate that OsIQD14 acts as a key factor in regulating MT rearrangements in rice hull cells and hence the grain shape, and allows effective local cell shape manipulation to improve the rice yield trait.
PMID: 31622529
Elife , IF:7.08 , 2020 May , V9 doi: 10.7554/eLife.55832
Temporal integration of auxin information for the regulation of patterning.
Laboratoire Reproduction et Developpement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, Inria, Lyon, France.; Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany.
Positional information is essential for coordinating the development of multicellular organisms. In plants, positional information provided by the hormone auxin regulates rhythmic organ production at the shoot apex, but the spatio-temporal dynamics of auxin gradients is unknown. We used quantitative imaging to demonstrate that auxin carries high-definition graded information not only in space but also in time. We show that, during organogenesis, temporal patterns of auxin arise from rhythmic centrifugal waves of high auxin travelling through the tissue faster than growth. We further demonstrate that temporal integration of auxin concentration is required to trigger the auxin-dependent transcription associated with organogenesis. This provides a mechanism to temporally differentiate sites of organ initiation and exemplifies how spatio-temporal positional information can be used to create rhythmicity.
PMID: 32379043
Plant Cell Environ , IF:6.362 , 2020 May doi: 10.1111/pce.13786
Mutation of MEDIATOR 18 and chromate trigger twinning of the primary root meristem in Arabidopsis.
Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Mexico.; Facultad de Quimico Farmacobiologia, Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Mexico.; CONACYT, Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo. Edificio B3, Ciudad Universitaria, Morelia, Mexico.; Unidad de Genomica Avanzada, Laboratorio Nacional de Genomica para la Biodiversidad, Centro de Investigacion y de Estudios Avanzados del IPN, Campus Irapuato, Guanajuato, Mexico.; Facultad de Biologia, Universidad Michoacana de San Nicolas de Hidalgo. Edificio R, Ciudad Universitaria, Morelia, Mexico.
Plants adapt to soil injury and biotic stress via cell regeneration. In Arabidopsis, root tip damage by genotoxic agents, antibiotics, UV light and cutting induces a program that recovers the missing tissues through activation of stem cells and involves ethylene response factor 115 (ERF115), which triggers cell replenishment. Here, we show that mutation of the gene encoding an MED18 subunit of the transcriptional MEDIATOR complex and chromate [Cr(VI)], an environmental pollutant, synergistically trigger a developmental program that enables the splitting of the meristem in vivo to produce twin roots. Expression of the quiescent centre gene marker WOX5, auxin-inducible DR5:GFP reporter and the ERF115 factor traced the changes in cell identity during the conversion of single primary root meristems into twin roots and were induced in an MED18 and chromate-dependent manner during the root twinning events, which also required auxin redistribution and signalling mediated by IAA14/SOLITARY ROOT (SLR1). Splitting of the root meristem allowed dichotomous root branching in Arabidopsis, a poorly understood process in which stem cells may act to enable whole organ regeneration.
PMID: 32400913
Plant J , IF:6.141 , 2020 May doi: 10.1111/tpj.14854
Direct and indirect targets of the arabidopsis seed transcription factor ABSCISIC ACID INSENSITIVE3.
UK Seed Biology Group, Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546-0312, USA.; UK Seed Biology Group, Department of Horticulture, University of Kentucky, Lexington, KY, 40546-0312, USA.
Arabidopsis thaliana ABSCISIC ACID INSENSITIVE3 (ABI3) is a transcription factor in the B3 domain family. ABI3, along with B3 domain transcription factors LEAFY COTYLEDON2 (LEC2) and FUSCA3 (FUS3), and LEC1, a subunit of the CCAAT box-binding complex, form the so-called LAFL network to control various aspects of seed development and maturation. ABI3 also contributes to the abscisic acid (ABA) response. We report on chromatin immunoprecipitation-tiling array experiments to map binding sites for ABI3 globally. We also assessed transcriptomes in response to ABI3 by comparing developing abi3-5 and wild-type seeds and combined this information to ascertain direct and indirect responsive ABI3 target genes. ABI3 can induce and repress its transcription of target genes directly and some intriguing differences exist in cis motifs between these groups of genes. Directly regulated targets reflect the role of ABI3 in seed maturation, desiccation tolerance, entry into a quiescent state and longevity. Interestingly, ABI3 directly represses a gene encoding a microRNA (MIR160B) that targets AUXIN RESPONSE FACTOR (ARF)10 and ARF16 that are involved in establishment of dormancy. In addition, ABI3, like FUS3, regulates genes encoding MIR156 but while FUS3 only induces genes encoding this product, ABI3 induces these genes during the early stages of seed development, but represses these genes during late development. The interplay between ABI3, the other LAFL genes, and the VP1/ABI3-LIKE (VAL) genes, which are involved in the transition to seedling development are examined and reveal complex interactions controlling development.
PMID: 32445409
Plant J , IF:6.141 , 2020 May doi: 10.1111/tpj.14853
The plant beneficial rhizobacterium Achromobacter sp. 5B1 influences root development through auxin signaling and redistribution.
Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio B3, Ciudad Universitaria, Morelia, Michoacan, C. P. 58030, Mexico.; Red de Estudios Moleculares Avanzados, Instituto de Ecologia A. C., Carretera Antigua a Coatepec 351 El Haya, Xalapa, Veracruz, 91070, Mexico.; Facultad de Ciencias Biologicas, Universidad Juarez del Estado de Durango, Av. Universidad S/N, Frac. Filadelfia, Gomez Palacio, Durango, C.P. 35010, Mexico.
Roots provide physical and nutritional support to plant organs that are above ground and play critical roles for adaptation via intricate movements and growth patterns. Through screening the effects of bacterial isolates from roots of halophyte Mesquite (Prosopis sp.) on Arabidopsis thaliana, we identified Achromobacter sp. 5B1 as a probiotic bacterium that influences plant functional traits. Detailed genetic and architectural analyses in Arabidopsis grown in vitro and in soil, cell division measurements, auxin transport and response gene expression and brefeldin A treatments demonstrated that root colonization with Achromobacter sp. 5B1 changes the growth and branching patterns of roots, which were related to auxin perception and redistribution. Expression analysis of auxin transport and signaling revealed a redistribution of auxin within the primary root tip of wild-type seedlings by Achromobacter sp. 5B1 that is disrupted by brefeldin A and correlates with repression of auxin transporters PIN1 and PIN7 in root provasculature, and PIN2 in the epidermis and cortex of the root tip, whereas expression of PIN3 was enhanced in the columella. In seedlings harboring AUX1, EIR1, AXR1, ARF7ARF19, TIR1AFB2AFB3 single, double or triple loss-of-function mutations, or in a dominant (gain-of-function) mutant of SLR1, the bacterium caused primary roots to form supercoils that are devoid of lateral roots. The changes in growth and root architecture elicited by the bacterium helped Arabidopsis seedlings to resist salt stress better. Thus, Achromobacter sp. 5B1 fine tunes both root movements and the auxin response, which may be important for plant growth and environmental adaptation.
PMID: 32445404
Plant J , IF:6.141 , 2020 May doi: 10.1111/tpj.14803
CpARF2 and CpEIL1 interact to mediate auxin-ethylene interaction and regulate fruit ripening in papaya.
Life Science and Technology School, Lingnan Normal University, Zhanjiang, 524048, China.; College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310035, China.; College of Bioscience and Technology, Hunan Agricultural University, Changsha, 410128, China.
Papaya (Carica papaya L.) is a commercially important fruit crop. Various phytohormones, particularly ethylene and auxin, control papaya fruit ripening. However, little is known about the interaction between auxin and ethylene signaling during the fruit ripening process. In the present study, we determined that the interaction between the CpARF2 and CpEIL1 mediates the interaction between auxin and ethylene signaling to regulate fruit ripening in papaya. We identified the ethylene-induced auxin response factor CpARF2 and demonstrated that it is essential for fruit ripening in papaya. CpARF2 interacts with an important ethylene signal transcription factor CpEIL1, thus increasing the CpEIL1-mediated transcription of the fruit ripening-associated genes CpACS1, CpACO1, CpXTH12 and CpPE51. Moreover, CpEIL1 is ubiquitinated by CpEBF1 and is degraded through the 26S proteasome pathway. However, CpARF2 weakens the CpEBF1-CpEIL1 interaction and interferes with CpEBF1-mediated degradation of CpEIL1, promoting fruit ripening. Therefore, CpARF2 functions as an integrator in the auxin-ethylene interaction and regulates fruit ripening by stabilizing CpEIL1 protein and promoting the transcriptional activity of CpEIL1. To our knowledge, we have revealed a novel module of CpARF2/CpEIL1/CpEBF1 that fine-tune fruit ripening in papaya. Manipulating this mechanism could help growers tightly control papaya fruit ripening and prolong shelf life.
PMID: 32391615
J Exp Bot , IF:5.908 , 2020 May doi: 10.1093/jxb/eraa209
Homeobox transcription factor OsZHD2 promotes root meristem activity in rice by inducing ethylene biosynthesis.
Crop Biotech Institute and Graduate School of Biotechnology, Kyung Hee University, Yongin, Korea.; Department of Plant Bioscience, Pusan National University, Miryang, Korea.; Department of Crop Genomics and Genetic Improvement, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.; Agricultural Research Centre For International Development, Paris, France.; Department of Biology, Sunchon National University, Sunchon, Chonnam, Korea.; National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan.; Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China; School of Agriculture, Food and Wine, University of Adelaide Urrbrae, SA, Australia.; Section of Cell and Developmental Biology, University of California San Diego, Gilman Drive, La Jolla, CA.
Root meristem activity is the most critical process influencing root development. Although several regulatory factors that regulate meristem activity have been identified in rice, studies on the enhancement of meristem activity in roots are limited. We identified a T-DNA activation tagging line of a zinc-finger homeobox gene, OsZHD2, which has longer seminal and lateral roots due to increased meristem activity. The phenotypes were confirmed in the transgenic plants overexpressing OsZHD2. In addition, the overexpressing plants enhanced grain yield under low nutrient and paddy field conditions. OsZHD2 was preferentially expressed in shoot apical meristem and root tips. Transcriptome analyses and qRT-PCR experiments on roots from the activation tagging line and wild type (WT) showed that genes for ethylene biosynthesis were up-regulated in the activation line. Ethylene levels were higher in the activation lines compared to the WT. ChIP assay results suggested that OsZHD2 induces ethylene biosynthesis by controlling ACS5 directly. Treatment with ACC, an ethylene precursor, induced the expression of DR5 reporter at the root tip and stele, whereas an ethylene biosynthesis inhibitor, AVG, treatment decreased that expression in both WT and OsZHD2 overexpression line. These observations suggest that OsZHD2 enhances root meristem activity by influencing ethylene biosynthesis and, in turn, auxin.
PMID: 32449922
J Exp Bot , IF:5.908 , 2020 May doi: 10.1093/jxb/eraa242
The Arabidopsis NRT1.1 transceptor coordinately controls auxin biosynthesis and transport to regulate root branching in response to nitrate.
BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France.; Site de Bellepierre, UFR Sante, Universite de la Reunion, 1 Allee des Aigues Marines, Saint Denis Cedex, France.; Institute of Science and Technology Austria, Klosterneuburg, Austria.; Instituto Universitario de Biotecnologia de Asturias, Departamento de Biologia de Organismos y Sistemas, Universidad de Oviedo, Spain.; School of Life and Environmental Sciences, F22 Life, Earth and Environmental Sciences Building, University of Sydney NSW, Australia.
In agricultural systems, nitrate is the main source of nitrogen available for plants. Besides its role as a nutrient, nitrate has been shown to act as a signal molecule for plant growth, development and stress responses. In Arabidopsis, the NRT1.1 nitrate transceptor represses lateral root (LR) development at low nitrate availability by promoting auxin basipetal transport out of the LR primordia (LRPs). In addition, our present study shows that NRT1.1 acts as a negative regulator of the TAR2 auxin biosynthetic gene expression in the root stele. This is expected to repress local auxin biosynthesis and thus to reduce acropetal auxin supply to the LRPs. Moreover, NRT1.1 also negatively affects expression of the LAX3 auxin influx carrier, thus preventing cell wall remodeling required for overlying tissues separation during LRP emergence. Both NRT1.1-mediated repression of TAR2 and LAX3 are suppressed at high nitrate availability, resulting in the nitrate induction of TAR2 and LAX3 expression that is required for optimal stimulation of LR development by nitrate. Altogether, our results indicate that the NRT1.1 transceptor coordinately controls several crucial auxin-associated processes required for LRP development, and as a consequence that NRT1.1 plays a much more integrated role than previously anticipated in regulating the nitrate response of root system architecture.
PMID: 32428238
J Exp Bot , IF:5.908 , 2020 May , V71 (9) : P2740-2751 doi: 10.1093/jxb/eraa021
Moderate water stress in rice induces rhizosheath formation associated with abscisic acid and auxin responses.
Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, China.; Institute of Oceanography, Minjiang University, Fuzhou, China.; Department of Biology, Hong Kong Baptist University, State Key Laboratory of Agrobiotechnology in the Chinese University of Hong Kong, Hong Kong, China.
The rhizosheath is known to be beneficial for drought resistance in many plants, but the regulation of rhizosheath formation in rice plants is unclear. Here, we investigate rhizosheath formation in different rice varieties and root hair mutants. Our results showed that moderate water stress in rice induced rhizosheath formation. The soil porosity and water content were higher in the rice rhizosheath than in the rice bulk soil under moderate water stress. Additionally, rhizosheath formation in short root hair mutants was lower than in wild-type rice under moderate water stress. Moreover, transcriptomic results indicated that abscisic acid (ABA) and auxin were involved in root and root hair responses in rhizosheath formation. Further, blocking ABA and auxin pathways in wild type and in rhl1-1, the shortest root hair mutant, rhizosheath formation and root hair length were significantly decreased under moderate water stress. However, wild type plants maintained a higher root ABA content, root basipetal auxin transport, root hair length, and amount of rhizosheath than did rhl1-1. Our results suggest that moderate water stress in rice induces rhizosheath formation by modulating the ABA and auxin responses to regulate root and root hair growth, which may be used to breed rice varieties resistant to drought.
PMID: 32053723
J Exp Bot , IF:5.908 , 2020 May , V71 (10) : P2982-2994 doi: 10.1093/jxb/eraa063
Cellulose synthase interactive1- and microtubule-dependent cell wall architecture is required for acid growth in Arabidopsis hypocotyls.
Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA.; Department of Biology, Pennsylvania State University, University Park, PA, USA.; Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
Auxin-induced cell elongation relies in part on the acidification of the cell wall, a process known as acid growth that presumably triggers expansin-mediated wall loosening via altered interactions between cellulose microfibrils. Cellulose microfibrils are a major determinant for anisotropic growth and they provide the scaffold for cell wall assembly. Little is known about how acid growth depends on cell wall architecture. To explore the relationship between acid growth-mediated cell elongation and plant cell wall architecture, two mutants (jia1-1 and csi1-3) that are defective in cellulose biosynthesis and cellulose microfibril organization were analyzed. The study revealed that cell elongation is dependent on CSI1-mediated cell wall architecture but not on the overall crystalline cellulose content. We observed a correlation between loss of crossed-polylamellate walls and loss of auxin- and fusicoccin-induced cell growth in csi1-3. Furthermore, induced loss of crossed-polylamellate walls via disruption of cortical microtubules mimics the effect of csi1 in acid growth. We hypothesize that CSI1- and microtubule-dependent crossed-polylamellate walls are required for acid growth in Arabidopsis hypocotyls.
PMID: 32016356
J Exp Bot , IF:5.908 , 2020 May , V71 (10) : P2910-2921 doi: 10.1093/jxb/eraa061
Inhibition of jasmonate-mediated plant defences by the fungal metabolite higginsianin B.
Universite Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER, Thiverval-Grignon, France.; Centre National de la Recherche Scientifique, Institut de Chimie des Substances Naturelles ICSN, Gif-sur-Yvette, France.; Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, Halle (Saale), Germany.; Chemical Biology Laboratory, Max Planck Institute for Plant Breeding Research, Cologne, Germany.; Department of Cell Biology and Biophysics, Faculty of Biology, National and Kapodistrian University of Athens, Greece.
Infection of Arabidopsis thaliana by the ascomycete fungus Colletotrichum higginsianum is characterized by an early symptomless biotrophic phase followed by a destructive necrotrophic phase. The fungal genome contains 77 secondary metabolism-related biosynthetic gene clusters, whose expression during the infection process is tightly regulated. Deleting CclA, a chromatin regulator involved in the repression of some biosynthetic gene clusters through H3K4 trimethylation, allowed overproduction of three families of terpenoids and isolation of 12 different molecules. These natural products were tested in combination with methyl jasmonate, an elicitor of jasmonate responses, for their capacity to alter defence gene induction in Arabidopsis. Higginsianin B inhibited methyl jasmonate-triggered expression of the defence reporter VSP1p:GUS, suggesting it may block bioactive jasmonoyl isoleucine (JA-Ile) synthesis or signalling in planta. Using the JA-Ile sensor Jas9-VENUS, we found that higginsianin B, but not three other structurally related molecules, suppressed JA-Ile signalling by preventing the degradation of JAZ proteins, the repressors of jasmonate responses. Higginsianin B likely blocks the 26S proteasome-dependent degradation of JAZ proteins because it inhibited chymotrypsin- and caspase-like protease activities. The inhibition of target degradation by higginsianin B also extended to auxin signalling, as higginsianin B treatment reduced auxin-dependent expression of DR5p:GUS. Overall, our data indicate that specific fungal secondary metabolites can act similarly to protein effectors to subvert plant immune and developmental responses.
PMID: 32006004
J Exp Bot , IF:5.908 , 2020 May , V71 (9) : P2612-2628 doi: 10.1093/jxb/eraa041
Symplasmic isolation marks cell fate changes during somatic embryogenesis.
Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland.; Bioscience, Wageningen University and Research, AA Wageningen, Netherlands.; Laboratory of Molecular Biology, Wageningen University and Research, AA Wageningen, Netherlands.; Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in KatowiceKatowice, Poland.
Cell-to-cell signalling is a major mechanism controlling plant morphogenesis. Transport of signalling molecules through plasmodesmata is one way in which plants promote or restrict intercellular signalling over short distances. Plasmodesmata are membrane-lined pores between cells that regulate the intercellular flow of signalling molecules through changes in their size, creating symplasmic fields of connected cells. Here we examine the role of plasmodesmata and symplasmic communication in the establishment of plant cell totipotency, using somatic embryo induction from Arabidopsis explants as a model system. Cell-to-cell communication was evaluated using fluorescent tracers, supplemented with histological and ultrastructural analysis, and correlated with expression of a WOX2 embryo reporter. We showed that embryogenic cells are isolated symplasmically from non-embryogenic cells regardless of the explant type (immature zygotic embryos or seedlings) and inducer system (2,4-dichlorophenoxyacetic acid or the BABY BOOM (BBM) transcription factor), but that the symplasmic domains in different explants differ with respect to the maximum size of molecule capable of moving through the plasmodesmata. Callose deposition in plasmodesmata preceded WOX2 expression in future sites of somatic embryo development, but later was greatly reduced in WOX2-expressing domains. Callose deposition was also associated with a decrease DR5 auxin response in embryogenic tissue. Treatment of explants with the callose biosynthesis inhibitor 2-deoxy-D-glucose supressed somatic embryo formation in all three systems studied, and also blocked the observed decrease in DR5 expression. Together these data suggest that callose deposition at plasmodesmata is required for symplasmic isolation and establishment of cell totipotency in Arabidopsis.
PMID: 31974549
Development , IF:5.611 , 2020 May , V147 (11) doi: 10.1242/dev.184762
VAPYRIN-like is required for development of the moss Physcomitrella patens.
Department of Biology, University of Fribourg, 1700-Fribourg, Switzerland.; Institut de Biologie, Universite de Neuchatel, 2000-Neuchatel, Switzerland.; Laboratoire de Recherche en Sciences Vegetales, Universite de Toulouse, CNRS, Auzeville, 31326 Castanet Tolosan, France.; Department of Biology, University of Fribourg, 1700-Fribourg, Switzerland didier.reinhardt@unifr.ch.
The VAPYRIN (VPY) gene in Medicago truncatula and Petunia hybrida is required for arbuscular mycorrhizal (AM) symbiosis. The moss Physcomitrella patens has a close homolog (VPY-like, VPYL), although it does not form AM. Here, we explore the phylogeny of VPY and VPYL in land plants, and study the expression and developmental function of VPYL in P patens We show that VPYL is expressed primarily in the protonema, the early filamentous stage of moss development, and later in rhizoids arising from the leafy gametophores and in adult phyllids. Knockout mutants have specific phenotypes in branching of the protonema and in cell division of the leaves (phyllids) in gametophores. The mutants are responsive to auxin and strigolactone, which are involved in regulation of protonemal branching, indicating that hormonal signaling in the mutants is not affected in hormonal signaling. Taken together, these results suggest that VPYL exerts negative regulation of protonemal branching and cell division in phyllids. We discuss VPY and VPYL phylogeny and function in land plants in the context of AM symbiosis in angiosperms and development in the moss.
PMID: 32376679
Development , IF:5.611 , 2020 May , V147 (10) doi: 10.1242/dev.183681
Multi-level analysis of the interactions between REVOLUTA and MORE AXILLARY BRANCHES 2 in controlling plant development reveals parallel, independent and antagonistic functions.
Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.; Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.; Centre for Plant Molecular Biology (ZMBP), University of Tubingen, Auf der Morgenstelle 32, 72076 Tubingen, Germany.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and National Center for Plant Gene Research, Beijing 100101, China.; Copenhagen Plant Science Centre, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark wenkel@plen.ku.dk.; NovoCrops Center, PLEN, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
Class III homeodomain leucine zipper (HD-ZIPIII) transcription factors play fundamental roles in controlling plant development. The known HD-ZIPIII target genes encode proteins involved in the production and dissipation of the auxin signal, HD-ZIPII transcription factors and components that feedback to regulate HD-ZIPIII expression or protein activity. Here, we have investigated the regulatory hierarchies of the control of MORE AXILLARY BRANCHES2 (MAX2) by the HD-ZIPIII protein REVOLUTA (REV). We found that REV can interact with the promoter of MAX2 In agreement, rev10D gain-of-function mutants had increased levels of MAX2 expression, while rev loss-of-function mutants showed lower levels of MAX2 in some tissues. Like REV, MAX2 plays known roles in the control of plant architecture, photobiology and senescence, which prompted us to initiate a multi-level analysis of growth phenotypes of hd-zipIII, max2 and respective higher order mutants thereof. Our data suggest a complex relationship of synergistic and antagonistic activities between REV and MAX2; these interactions appear to depend on the developmental context and do not all involve the direct regulation of MAX2 by REV.
PMID: 32345745
Biochem Pharmacol , IF:4.96 , 2020 May , V175 : P113866 doi: 10.1016/j.bcp.2020.113866
Phytohormones: Multifunctional nutraceuticals against metabolic syndrome and comorbid diseases.
VIB-UGent Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium; VIB-UGent Center for Plant Systems Biology, VIB, Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.; VIB-UGent Center for Plant Systems Biology, VIB, Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.; VIB-UGent Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.; Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.; VIB-UGent Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium. Electronic address: Jens.Staal@irc.vib-UGent.be.; VIB-UGent Center for Inflammation Research, VIB, Ghent, Belgium; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium. Electronic address: Rudi.Beyaert@irc.vib-UGent.be.
Metabolic syndrome is characterized by the co-occurrence of diverse symptoms initiating the development of type 2 diabetes, cardiovascular diseases, and a variety of comorbid diseases. The complex constellation of numerous comorbidities makes it difficult to develop common therapeutic approaches that ameliorate these pathological features simultaneously. The plant hormones abscisic acid, salicylic acid, auxin, and cytokinins, have shown promising anti-inflammatory and pro-metabolic effects that could mitigate several disorders relevant to metabolic syndrome. Intriguingly, besides plants, human cells and gut microbes also endogenously produce these molecules, indicating a role in the complex interplay between inflammatory responses associated with metabolic syndrome, the gut microbiome, and nutrition. Here, we introduce how bioactive phytohormones can be generated endogenously and through the gut microbiome. These molecules subsequently influence immune responses and metabolism. We also elaborate on how phytohormones can beneficially modulate metabolic syndrome comorbidities, and propose them as nutraceuticals.
PMID: 32088261
J Integr Plant Biol , IF:4.885 , 2020 May , V62 (5) : P652-667 doi: 10.1111/jipb.12822
Photoexcited phytochrome B interacts with brassinazole resistant 1 to repress brassinosteroid signaling in Arabidopsis.
National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, the Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Photoreceptor phytochrome B (phyB) mediates a variety of light responses in plants. To further elucidate the molecular mechanisms of phyB-regulated hypocotyl elongation, we performed firefly luciferase complementation imaging (LCI) screening for phyB-interacting transcription factors (TFs). LCI assays showed that phyB possibly interacts with brassinazoleresistant 1 (BZR1), BZR2, AUXIN RESPONSE FACTOR 6 (ARF6), and several WRKY DNA-binding TFs in a red light-dependent manner. Furthermore, biochemical assays demonstrated that photoexcited phyB specifically interacts with non-phosphorylated BZR1, the physiologically active form of a master TF in brassinosteroid (BR) signaling, and this interaction can be competitively interfered by phytochrome-interacting factor 4. Furthermore, we showed that phyB can directly interact with the DNA-binding domain of BZR1 and affect the enrichment of BZR1 on the chromatin of target genes. Moreover, our genetic evidence and RNA-seq analysis demonstrated that phyB negatively regulates BR signaling. Together, we revealed that photoexcited phyB directly interacts with the TF BZR1 to repress BR signaling in Arabidopsis.
PMID: 31081597
J Integr Plant Biol , IF:4.885 , 2020 May , V62 (5) : P581-600 doi: 10.1111/jipb.12820
Tillering and small grain 1 dominates the tryptophan aminotransferase family required for local auxin biosynthesis in rice.
National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences and Collaborative Innovation Center of Genetics & Development, Shanghai Institute of Plant Physiology & Ecology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.; University of the Chinese Academy of Sciences, Beijing, 100049, China.; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
Auxin is a crucial phytohormone, controlling multiple aspects of plant growth and responses to the changing environment. However, the role of local auxin biosynthesis in specific developmental programs remains unknown in crops. This study characterized the rice tillering and small grain 1 (tsg1) mutant, which has more tillers but a smaller panicle and grain size resulting from a reduction in endogenous auxin. TSG1 encodes a tryptophan aminotransferase that is allelic to the FISH BONE (FIB) gene. The tsg1 mutant showed hypersensitivity to indole-3-acetic acid and the competitive inhibitor of aminotransferase, L-kynurenine. TSG1 knockout resulted in an increased tiller number but reduction in grain number and size, and decrease in height. Meanwhile, deletion of the TSG1 homologs OsTAR1, OsTARL1, and OsTARL2 caused no obvious changes, although the phenotype of the TSG1/OsTAR1 double mutant was intensified and infertile, suggesting gene redundancy in the rice tryptophan aminotransferase family. Interestingly, TSG1 and OsTAR1, but not OsTARL1 and OsTARL2, displayed marked aminotransferase activity. Meanwhile, subcellular localization was identified as the endoplasmic reticulum, while phylogenetic analysis revealed functional divergence of TSG1 and OsTAR1 from OsTARL1 and OsTARL2. These findings suggest that TSG1 dominates the tryptophan aminotransferase family, playing a prominent role in local auxin biosynthesis in rice.
PMID: 31081210
J Integr Plant Biol , IF:4.885 , 2020 May , V62 (5) : P702-715 doi: 10.1111/jipb.12816
Osa-miR167d facilitates infection of Magnaporthe oryzae in rice.
Rice Research Institute and Key Lab for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China.
MicroRNAs (miRNAs) play important roles in rice response to Magnaporthe oryzae, the causative agent of rice blast disease. Studying the roles of rice miRNAs is of great significance for the disease control. Osa-miR167d belongs to a conserved miRNA family targeting auxin responsive factor (ARF) genes that act in developmental and stress-induced responses. Here, we show that Osa-miR167d plays a negative role in rice immunity against M. oryzae by suppressing its target gene. The expression of Osa-miR167d was significantly suppressed in a resistant accession at and after 24 h post inoculation (hpi), however, its expression was significantly increased at 24 hpi in the susceptible accession upon M. oryzae infection. Transgenic rice lines over-expressing Osa-miR167d were highly susceptible to multiple blast fungal strains. By contrast, transgenic lines expressing a target mimicry to block Osa-miR167d enhanced resistance to rice blast disease. In addition, knocking out the target gene ARF12 led to hyper-susceptibility to multiple blast fungal strains. Taken together, our results indicate that Osa-miR167d negatively regulate rice immunity to facilitate the infection of M. oryzae by downregulating ARF12. Thus, Osa-miR167d-ARF12 regulatory module could be valuable in improvement of blast-disease resistance.
PMID: 31001874
Mol Cell Proteomics , IF:4.87 , 2020 May doi: 10.1074/mcp.RA119.001826
The CEP5 peptide promotes abiotic stress tolerance, as revealed by quantitative proteomics, and attenuates the AUX/IAA equilibrium in Arabidopsis.
University of Nottingham, United Kingdom.; VIB Center for Plant Systems Biology, Belgium.; VIB Center for Plant Systems Biology, Ecuador.; POSTECH Biotech Center, Lao People's Democratic Republic.; University of Washington, United States.; University of Leeds, United Kingdom.; Heinrich-Heine University, Germany.; VIB-UGent Center for Medical Biotechnology, Belgium.; VIB-Ghent University, Belgium.; Umea Plant Science Centre, Sweden.; Pohang University of Science and Technology, Republic of Korea.; University of Nottingham, United Kingdom ive.desmet@psb.vib-ugent.be.
Peptides derived from non-functional precursors play important roles in various developmental processes, but also in (a)biotic stress signaling. Our (phospho)proteome-wide analyses of C-terminally encoded peptide 5 (CEP5)-mediated changes revealed an impact on abiotic stress-related processes. Drought has a dramatic impact on plant growth, development and reproduction, and the plant hormone auxin plays a role in drought responses. Our genetic, physiological, biochemical and pharmacological results demonstrated that CEP5-mediated signaling is relevant for osmotic and drought stress tolerance in Arabidopsis, and that CEP5 specifically counteracts auxin effects. Specifically, we found that CEP5 signaling stabilizes AUX/IAA transcriptional repressors, suggesting the existence of a novel peptide-dependent control mechanism that tunes auxin signaling. These observations align with the recently described role of AUX/IAAs in stress tolerance and provide a novel role for CEP5 in osmotic and drought stress tolerance.
PMID: 32404488
Int J Mol Sci , IF:4.556 , 2020 May , V21 (11) doi: 10.3390/ijms21113815
Disruption of the Auxin Gradient in the Abscission Zone Area Evokes Asymmetrical Changes Leading to Flower Separation in Yellow Lupine.
Department of Plant Physiology, Institute of Biology, Faculty of Agriculture and Biology, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland.; Chair of Plant Physiology and Biotechnology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, 1 Lwowska Street, 87-100 Torun, Poland.; Department of Plant Physiology and Biotechnology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland.; Plant Reproductive Biology and Advanced Microscopy Laboratory, Department of Biochemistry, Cell and Molecular Biology of Plants, Estacion Experimental del Zaidin, Spanish National Research Council (CSIC), Profesor Albareda 1, E-18008 Granada, Spain.
How auxin transport regulates organ abscission is a long-standing and intriguing question. Polar auxin transport across the abscission zone (AZ) plays a more important role in the regulation of abscission than a local concentration of this hormone. We recently reported the existence of a spatiotemporal sequential pattern of the indole-3-acetic acid (IAA) localization in the area of the yellow lupine AZ, which is a place of flower detachment. In this study, we performed analyses of AZ following treatment with an inhibitor of polar auxin transport (2,3,5-triiodobenzoic acid (TIBA)). Once we applied TIBA directly onto the AZ, we observed a strong response as demonstrated by enhanced flower abscission. To elucidate the molecular events caused by the inhibition of auxin movement, we divided the AZ into the distal and proximal part. TIBA triggered the formation of the IAA gradient between these two parts. The AZ-marker genes, which encode the downstream molecular components of the inflorescence deficient in abscission (IDA)-signaling system executing the abscission, were expressed in the distal part. The accumulation of IAA in the proximal area accelerated the biosynthesis of abscisic acid and ethylene (stimulators of flower separation), which was also reflected at the transcriptional level. Accumulated IAA up-regulated reactive oxygen species (ROS) detoxification mechanisms. Collectively, we provide new information regarding auxin-regulated processes operating in specific areas of the AZ.
PMID: 32471291
Int J Mol Sci , IF:4.556 , 2020 May , V21 (9) doi: 10.3390/ijms21093394
Different Roles of Auxins in Somatic Embryogenesis Efficiency in Two Picea Species.
Institute of Dendrology, Polish Academy of Sciences, 62-035 Kornik, Poland.
The effects of auxins 2,4-D (2,4-dichlorophenoxyacetic acid), NAA (1-naphthaleneacetic acid) or picloram (4-amino-3,5,6-trichloropicolinic acid; 9 microM) and cytokinin BA (benzyloadenine; 4.5 microM) applied in the early stages of somatic embryogenesis (SE) on specific stages of SE in Picea abies and P. omorika were investigated. The highest SE initiation frequency was obtained after 2,4-D application in P. omorika (22.00%) and picloram application in P. abies (10.48%). NAA treatment significantly promoted embryogenic tissue (ET) proliferation in P. abies, while 2,4-D treatment reduced it. This reduction was related to the oxidative stress level, which was lower with the presence of NAA in the proliferation medium and higher with the presence of 2,4-D. The reduced oxidative stress level after NAA treatment suggests that hydrogen peroxide (H2O2) acts as a signalling molecule and promotes ET proliferation. NAA and picloram in the proliferation medium decreased the further production and maturation of P. omorika somatic embryos compared with that under 2,4-D. The quality of the germinated P. abies embryos and their development into plantlets depended on the auxin type and were the highest in NAA-originated embryos. These results show that different auxin types can generate different physiological responses in plant materials during SE in both spruce species.
PMID: 32403374
Int J Mol Sci , IF:4.556 , 2020 May , V21 (9) doi: 10.3390/ijms21093250
The HD-ZIP II Transcription Factors Regulate Plant Architecture through the Auxin Pathway.
College of Life Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
The homeodomain-leucine zipper (HD-ZIP) family transcription factors play important roles in plant growth and development. However, the underlying mechanisms remain largely unclear. Here we found that ATHB2, encoding a HD-ZIP transcription factor, is an early auxin responsive gene. Phenotypic analyses show that overexpression of ATHB2 impairs plant architecture, including reduced plant height and small leaves, and also reduces auxin response in leaves when grown in soil. Simultaneously, the seedlings with chemical induction of ATHB2 exhibit abnormal root gravitropism, a typical auxin-related phenotype. We further show that the auxin response pattern is altered in roots of the inducible ATHB2 seedlings. Consistently, the transcript levels of some auxin biosynthetic and transport genes are significantly decreased in these transgenic seedlings. Further, protein and promoter sequence analyses in common wheat showed that the HD-ZIP II subfamily transcription factors have highly conserved motifs and most of these encoding gene promoters contain the canonical auxin-responsive elements. Expression analyses confirm that some of these HD-ZIP II genes are indeed regulated by auxin in wheat. Together, our results suggest that the HD-ZIP II subfamily transcription factors regulate plant development possibly through the auxin pathway in plants.
PMID: 32375344
Microorganisms , IF:4.152 , 2020 May , V8 (5) doi: 10.3390/microorganisms8050702
Bacillus telluris sp. nov. Isolated from Greenhouse Soil in Beijing, China.
Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China; guohebao0409@163.com (H.-B.G.).
A novel Gram-stain-positive, rod-shaped, endospore-forming bacterium, which we designated as strain 03113(T), was isolated from greenhouse soil in Beijing, China. Phylogenetic analysis based on 16S rRNA gene sequences showed strain 03113(T) is in the genus Bacillus and had the highest similarity to Bacillus solani CCTCC AB 2014277(T) (98.14%). The strain grew at 4 degrees C-50 degrees C (optimum 37 degrees C), with 0-10% (w/v) NaCl (optimum 5%), and in the range of pH 3.0-12.0 (optimum pH 8.0). Menaquinone was identified as MK-7, and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. The main major cellular fatty acids detected were anteiso-C15:0 (51.35%) and iso-C15:0 (11.06%), which are the predominant cellular fatty acids found in all recognized members of the genus Bacillus. The 16S rRNA gene sequence and core-genome analysis, the average nucleotide identity (ANI), and in silico DNA-DNA hybridization (DDH) value between strain 03113(T) and the most closely related species were 70.5% and 22.6%, respectively, which supported our conclusion that 03113(T) represented a novel species in the genus Bacillus. We demonstrated that type strain 03113(T) (=ACCC 03113(T)=JCM 33017(T)) was a novel species in the genus Bacillus, and the name Bacillus telluris sp. nov. was proposed. Strain 03113(T) secreted auxin IAA and carried the nitrogenase iron protein (nifH) gene, which indicated that strain 03113(T) has the potential to fix nitrogen and promote plant growth. Bacillus telluris sp. nov. 03113(T) is a potential candidate for the biofertilizers of organic agriculture areas.
PMID: 32397635
Physiol Plant , IF:4.148 , 2020 May doi: 10.1111/ppl.13118
What drives interspecies graft union success? Exploring the role of phylogenetic relatedness and stem anatomy.
School of Natural Sciences, University of Tasmania, Hobart, 7001, Australia.
The underlying mechanisms that determine whether two species can form a successful graft union (graft compatibility) remain obscure. Two prominent hypotheses are (1) the more closely related species are, the higher the graft success and (2) the vascular anatomy at the graft junction influences graft success. In this paper these two hypotheses are examined in a systematic way using graft combinations selected from a range of (a) phylogenetically close and more distant legume species, (b) species displaying different germination patterns and (c) scions and rootstocks possessing contrasting stem tissues and vascular patterns. Relatedness of species was not a good predictor of graft compatibility, as vascular reconnection can occur between distantly related species and can fail to occur in some more closely related species. Similarly, neither the stem tissues present at the graft junction nor the vascular anatomy correlated with the success of vascular reconnection. Relatedness and stem anatomy therefore do not appear to be the determining factors in successful vascular reconnection after grafting in legumes. These results are discussed in conjunction with other hypotheses such as the role of auxin.
PMID: 32385889
Biomolecules , IF:4.082 , 2020 May , V10 (5) doi: 10.3390/biom10050746
Machine Learning Technology Reveals the Concealed Interactions of Phytohormones on Medicinal Plant In Vitro Organogenesis.
Applied Plant & Soil Biology, Plant Biology and Soil Science Department, Biology Faculty, University of Vigo, E-36310 Vigo, Spain.; CITACA-Agri-Food Research and Transfer Cluster, University of Vigo, E-32004 Ourense, Spain.; Pharmacology, Pharmacy and Pharmaceutical Technology Department, Faculty of Pharmacy, University of Santiago, E-15782 Santiago de Compostela, Spain.; Instituto de Investigacion Sanitaria de Santiago (IDIS), E-15782 Santiago de Compostela, Spain.
Organogenesis constitutes the biological feature driving plant in vitro regeneration, in which the role of plant hormones is crucial. The use of machine learning (ML) technology stands out as a novel approach to characterize the combined role of two phytohormones, the auxin indoleacetic acid (IAA) and the cytokinin 6-benzylaminopurine (BAP), on the in vitro organogenesis of unexploited medicinal plants from the Bryophyllum subgenus. The predictive model generated by neurofuzzy logic, a combination of artificial neural networks (ANNs) and fuzzy logic algorithms, was able to reveal the critical factors affecting such multifactorial process over the experimental dataset collected. The rules obtained along with the model allowed to decipher that BAP had a pleiotropic effect on the Bryophyllum spp., as it caused different organogenetic responses depending on its concentration and the genotype, including direct and indirect shoot organogenesis and callus formation. On the contrary, IAA showed an inhibiting role, restricted to indirect shoot regeneration. In this work, neurofuzzy logic emerged as a cutting-edge method to characterize the mechanism of action of two phytohormones, leading to the optimization of plant tissue culture protocols with high large-scale biotechnological applicability.
PMID: 32403395
Plant Cell Physiol , IF:4.062 , 2020 May doi: 10.1093/pcp/pcaa059
Seminal and Nodal Roots of Barley Differ in Anatomy, Proteome and Nitrate Uptake Capacity.
Molecular Plant Nutrition, Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, Corrensstrasse 3, Gatersleben, Germany.; Proteomics Core Facility, SYBIOMA, KU Leuven, O&N II Herestraat 49 - bus 901, Leuven, Belgium.; Division of Crop Biotechnics, Department of Biosystems, KU Leuven, Willem de Croylaan 42 - Box 2455, Leuven, Belgium.
The root system of barley plants is composed of embryogenic, seminal roots, as well as lateral and nodal roots that are formed post-embryonically from seminal roots and from the basal part of shoots, respectively. Due to their distinct developmental origin, seminal and nodal roots may differ in function during plant development, however, a clear comparison between these two root types has not yet been undertaken. In this study, anatomical, proteomic and physiological traits were compared between seminal and nodal roots of similar developmental stage. Nodal roots have larger diameter, larger metaxylem area and a larger number of metaxylem vessels than seminal roots. Proteome profiling uncovered a set of root type-specific proteins, including proteins related to cell wall and cytoskeleton organization, which could potentially be implicated with differential metaxylem development. We also found that nodal roots have higher levels of auxin, which is known to trigger metaxylem development. At millimolar nitrate supply nodal roots had approximately twofold higher nitrate uptake and root-to-shoot translocation capacities than seminal roots, whereas no differences were found at micromolar nitrate supply. Since these marked differences were not reflected by the transcript levels of low-affinity nitrate transporter genes, we hypothesize that the larger metaxylem volume of nodal roots enhances predominantly the low-affinity uptake and translocation capacities of nutrients that are transported with the bulk flow of water, like nitrate.
PMID: 32379871
Ann Bot , IF:4.005 , 2020 May doi: 10.1093/aob/mcaa099
Differential regulatory pathways associated with drought-inhibition and post-drought recuperation of rhizome development in perennial grass.
College of Grassland Science and Technology, China Agricultural University; Beijing, PR China.; Department of Plant Biology and Pathology; Rutgers, the State University of New Jersey, New Brunswick, NJ, USA.; College of Agro-grassland Science, Nanjing Agricultural University; Nanjing, PR China.; College of Grassland Science, Gansu Agricultural University, Lanzhou, PR China.
BACKGROUND AND AIMS: Rhizomes are key organs for the establishment of perennial grass stands and adaptation to environmental stress. However, mechanisms regulating rhizome initiation and elongation under drought stress and during post-drought recovery remain unclear. The objective of this study is to investigate molecular factors and metabolic processes involved in drought effects and post-drought recovery in rhizome growth in perennial grass species by comparative transcriptomic and proteomic profiling. METHODS: Tall fescue (Festuca arundinacea) (B-type rhizome genotype, 'BR') plants were exposed to drought stress and re-watering in growth chambers. The number and length of rhizomes were measured following drought stress and re-watering. Hormone and sugar content were analyzed, and transcriptomic and proteomic analyses were performed to identify metabolic factors, genes and proteins associated with rhizome development. KEY RESULTS: Rhizome initiation and elongation were inhibited by drought stress, which were associated with increases in the content of abscisic acid (ABA) and soluble sugars, but a decline in the content of indoleacetic acid (IAA), zeatin riboside (ZR) and gibberellin (GA4). Genes involved in multiple metabolic processes and stress defense systems related to rhizome initiation exhibited different responses to drought stress, including ABA signaling, energy metabolism, and stress protection. Drought-inhibition of rhizome elongation could be mainly associated with the alteration of GA4 and antioxidants contents, energy metabolism and stress response proteins. Upon re-watering, new rhizomes were regenerated from rhizome nodes previously exposed to drought stress, which was accompanied by the decline in ABA content and increases in IAA, ZR, and GA4, as well as genes and proteins for auxin, lipids, lignin and nitrogen metabolism. CONCLUSIONS: Drought-inhibition of rhizome initiation and elongation in tall fescue was mainly associated with adjustments in hormone metabolism, carbohydrate metabolism and stress-defense systems. Rhizome regeneration in response to re-watering involved reactivation of hormone and lipid metabolism, secondary cell-wall development, and nitrogen remobilization and cycling.
PMID: 32445476
Ann Bot , IF:4.005 , 2020 May , V125 (6) : P905-923 doi: 10.1093/aob/mcaa022
Mutational analysis indicates that abnormalities in rhizobial infection and subsequent plant cell and bacteroid differentiation in pea (Pisum sativum) nodules coincide with abnormal cytokinin responses and localization.
All-Russia Research Institute for Agricultural Microbiology, Laboratory of Molecular and Cellular Biology, Saint Petersburg, Russia.; Saint Petersburg State University, Department of Genetics and Biotechnology, Universitetskaya embankment 7-9, Saint Petersburg, Russia.; Komarov Botanical Institute, Russian Academy of Sciences, Laboratory of Cellular and Molecular Mechanisms of Plant Development, Saint Petersburg, Russia.; Saint Petersburg Scientific Center Russian Academy of Sciences, Universitetskaya embankment 5, Saint Petersburg, Russia.
BACKGROUND AND AIMS: Recent findings indicate that Nod factor signalling is tightly interconnected with phytohormonal regulation that affects the development of nodules. Since the mechanisms of this interaction are still far from understood, here the distribution of cytokinin and auxin in pea (Pisum sativum) nodules was investigated. In addition, the effect of certain mutations blocking rhizobial infection and subsequent plant cell and bacteroid differentiation on cytokinin distribution in nodules was analysed. METHODS: Patterns of cytokinin and auxin in pea nodules were profiled using both responsive genetic constructs and antibodies. KEY RESULTS: In wild-type nodules, cytokinins were found in the meristem, infection zone and apical part of the nitrogen fixation zone, whereas auxin localization was restricted to the meristem and peripheral tissues. We found significantly altered cytokinin distribution in sym33 and sym40 pea mutants defective in IPD3/CYCLOPS and EFD transcription factors, respectively. In the sym33 mutants impaired in bacterial accommodation and subsequent nodule differentiation, cytokinin localization was mostly limited to the meristem. In addition, we found significantly decreased expression of LOG1 and A-type RR11 as well as KNOX3 and NIN genes in the sym33 mutants, which correlated with low cellular cytokinin levels. In the sym40 mutant, cytokinins were detected in the nodule infection zone but, in contrast to the wild type, they were absent in infection droplets. CONCLUSIONS: In conclusion, our findings suggest that enhanced cytokinin accumulation during the late stages of symbiosis development may be associated with bacterial penetration into the plant cells and subsequent plant cell and bacteroid differentiation.
PMID: 32198503
Sci Rep , IF:3.998 , 2020 May , V10 (1) : P8658 doi: 10.1038/s41598-020-65372-8
Nyctinastic thallus movement in the liverwort Marchantia polymorpha is regulated by a circadian clock.
Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvagen 18D, SE-75236, Uppsala, Sweden.; The Linnean Centre for Plant Biology in Uppsala, Uppsala, Sweden.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83, Umea, Sweden.; Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvagen 18D, SE-75236, Uppsala, Sweden. magnus.eklund@ebc.uu.se.; The Linnean Centre for Plant Biology in Uppsala, Uppsala, Sweden. magnus.eklund@ebc.uu.se.
The circadian clock coordinates an organism's growth, development and physiology with environmental factors. One illuminating example is the rhythmic growth of hypocotyls and cotyledons in Arabidopsis thaliana. Such daily oscillations in leaf position are often referred to as sleep movements or nyctinasty. Here, we report that plantlets of the liverwort Marchantia polymorpha show analogous rhythmic movements of thallus lobes, and that the circadian clock controls this rhythm, with auxin a likely output pathway affecting these movements. The mechanisms of this circadian clock are partly conserved as compared to angiosperms, with homologs to the core clock genes PRR, RVE and TOC1 forming a core transcriptional feedback loop also in M. polymorpha.
PMID: 32457350
Sci Rep , IF:3.998 , 2020 May , V10 (1) : P8196 doi: 10.1038/s41598-020-65125-7
Strawberry fatty acyl glycosides enhance disease protection, have antibiotic activity and stimulate plant growth.
Instituto de Tecnologia Agroindustrial del Noroeste Argentino (ITANOA), Estacion Experimental Agroindustrial Obispo Colombres (EEAOC)-Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (P.C. T4101), Las Talitas, Tucuman, Argentina.; Centro de Investigaciones en Hidratos de Carbono, Departamento de Quimica Organica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (P.C. C1428), Buenos Aires, Argentina.; Facultad de Agronomia y Zootecnia, Universidad Nacional de Tucuman (UNT), San Miguel de Tucuman (P.C. T4000), Tucuman, Argentina.; Instituto Superior de Investigaciones Biologicas (INSIBIO, CONICET-UNT) and Instituto de Quimica Biologica "Dr. Bernabe Bloj", Facultad de Bioquimica, Quimica y Farmacia, UNT, San Miguel de Tucuman (P.C. T4000), Tucuman, Argentina.; Instituto de Tecnologia Agroindustrial del Noroeste Argentino (ITANOA), Estacion Experimental Agroindustrial Obispo Colombres (EEAOC)-Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (P.C. T4101), Las Talitas, Tucuman, Argentina. bwelin@gmail.com.; Instituto de Tecnologia Agroindustrial del Noroeste Argentino (ITANOA), Estacion Experimental Agroindustrial Obispo Colombres (EEAOC)-Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (P.C. T4101), Las Talitas, Tucuman, Argentina. atiliocastagnaro@gmail.com.
An increasing interest in the development of products of natural origin for crop disease and pest control has emerged in the last decade. Here we introduce a new family of strawberry acyl glycosides (SAGs) formed by a trisaccharide (GalNAc-GalNAc-Glc) and a monounsaturated fatty acid of 6 to 12 carbon atoms linked to the glucose unit. Application of SAGs to Arabidopsis thaliana (hereafter Arabidopsis) plants triggered a transient oxidative burst, callose deposition and defense gene expression, accompanied by increased protection against two phytopathogens, Pseudomonas viridiflava and Botrytis cinerea. SAGs-induced disease protection was also demonstrated in soybean infected with the causal agent of target spot, Corynespora cassiicola. SAGs were shown to exhibit important antimicrobial activity against a wide-range of bacterial and fungal phytopathogens, most probably through membrane destabilization, and the potential use of SAGs as a biofungicide for postharvest disease protection was demonstrated on lemon fruits infected with Penicillium digitatum. Plant growth promotion by application of SAGs was shown by augmented primary root elongation, secondary roots development and increased siliques formation in Arabidopsis, whereas a significant increment in number of seed pods was demonstrated in soybean. Stimulation of radicle development and the induction of an auxin-responsive reporter system (DR5::GUS) in transgenic Arabidopsis plants, suggested that SAGs-stimulated growth at least partly acts through the auxin response pathway. These results indicate that strawberry fatty acid glycosides are promising candidates for the development of environmental-friendly products for disease management in soybean and lemon.
PMID: 32424195
Sci Rep , IF:3.998 , 2020 May , V10 (1) : P7801 doi: 10.1038/s41598-020-63952-2
Transcript profiling provides insights into molecular processes during shoot elongation in temperature-sensitive peach (Prunus persica).
College of Horticulture, Henan Agricultural University, Zhengzhou, 450002, China.; Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou, 450002, China.; College of Horticulture, Henan Agricultural University, Zhengzhou, 450002, China. jcfeng@henau.edu.cn.; Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou, 450002, China. jcfeng@henau.edu.cn.
Plant growth caused by ambient temperature is thought to be regulated by a complex transcriptional network. A temperature-sensitive peach (Prunus persica) was used to explore the mechanisms behind shoot internode elongation at elevated temperatures. There was a significantly positive correlation between the length of the terminal internode (TIL) and the maximum temperature three days prior to the measuring day. Four critical growth stages (initial period and initial elongation period at lower temperature, rapid growth period and stable growth period at higher temperature) were selected for comparative RNA-seq analysis. About 6.64G clean bases were obtained for each library, and 88.27% of the data were mapped to the reference genome. Differentially expressed gene (DEG) analysis among the three pairwise comparisons resulted in the detection of several genes related to the shoot elongation in temperature-sensitive peach. HSFAs were up-regulated in response to the elevated temperature, while the up-regulated expression of HSPs might influence hormone signaling pathways. Most of DEGs involved in auxin, abscisic acid and jasmonic acid were up-regulated, while some involved in cytokinin and brassinosteroid were down-regulated. Genes related to ethylene, salicylic acid and circadian rhythm were also differentially expressed. Genes related to aquaporins, expansins, pectinesterases and endoglucanase were up-regulated, which would promote cell elongation. These results lay a foundation for further dissection of the regulatory mechanisms underlying shoot elongation at elevated temperatures.
PMID: 32385278
Microbiol Res , IF:3.97 , 2020 May , V235 : P126449 doi: 10.1016/j.micres.2020.126449
Molecular imprints of plant beneficial Streptomyces sp. AC30 and AC40 reveal differential capabilities and strategies to counter environmental stresses.
College of Horticulture and Forestry, (Dr YS Parmar University of Horticulture and Forestry), Neri, Hamirpur, 177 001, HP, India. Electronic address: richaihbt332@gmail.com.; University Centre for Research and Development, Chandigarh University, 140413, India. Electronic address: ankvivek@gmail.com.; University Centre for Research and Development, Chandigarh University, 140413, India.; Bionivid Technology Private Limited Kasturi Nagar, Bangalore-560043, India.
Streptomyces and their biomolecules are well explored for antibiotics production, bioremediation and alleviating the plant stresses due to their plant beneficial attributes. Therefore, due to plethora of biological attributes, the accurate portraying of molecular capabilities of these microorganisms at genomic level is of paramount importance. Here, we have evaluated biochemical attributes of two Streptomyces sp. AC30and AC40 for different plant beneficial activities which are antagonistic to Fusarium oxysporum, Alternaria solani, Sclerotinia sclerotium and Phytopthora infestans. In parallel, the draft genomes of these strains were deduced to understand their genomic capabilities using Illumina platform. The complete genome of AC30and AC40 were 11,284,599 bp and 12,636,188bp in size with total G+C content of 62.36 and 54.75 %, respectively. Overall, higher number of genes (14,024) was reported for AC40 as compared to AC30 (12,476). The comparative genome organization revealed sharing of a few biosynthetic clusters as well as some exclusive biosynthetic clusters among both the strains. Further, expansion in the chitinases and glucanases was found in the genome of AC40. In addition, genes for 3-phytase and glycosyl hydrolase family 19 were restricted to AC40 only. The comparative genome study revealed presence of plant induced nitrilase in AC40 which is predicted for its role in IAA biosynthesis, release of ammonia, biotransformation of nitrile compounds to corresponding acids and bioremediation of soil containing nitrile compounds. For IAA and secondary metabolites biosynthesis, flavin-dependent monooxygenase, a rate limiting factor in Trp-dependent auxin biosynthesis pathway was found exclusive to AC30 genome. The comparative study revealed the diversification of few pathways/strategies to suppress plant pathogens and promote plant growth by Streptomyces strains.
PMID: 32114361
Pest Manag Sci , IF:3.75 , 2020 May doi: 10.1002/ps.5887
Identification of environmental factors that influence the likelihood of off-target movement of dicamba.
University of Missouri, Columbia, MO, USA.; University of Tennessee, Jackson, TN, USA.
BACKGROUND: Commercialization of dicamba-resistant soybean and cotton and subsequent post-emergence applications of dicamba contributed to at least 1.4 and 0.5 million hectares of dicamba-injured soybean in the United States in 2017 and 2018, respectively. This research was initiated to identify environmental factors that contribute to off-target dicamba movement. A survey was conducted following the 2017 growing season to collect information from dicamba applications that remained on the target field and those where dicamba moved. Weather and environmental data surrounding applications were collected and used to identify factors that reduce the likelihood of off-target movement. Soil pH was one factor identified in the model, and field experiments were conducted in 2018 and 2019 to validate the model. Three commercially-available dicamba formulations and one formulation currently in development were applied to soil at five distinct pH values. Sensitive soybean was used as a bioassay plant to detect dicamba volatilization. RESULTS: Wind speeds the day of and following application, nearest water source to the field, soybean production acreage in the county, and soil pH were identified as factors that influence the likelihood for off-target movement. In the field study, when dicamba was applied to pH-adjusted soil and placed under low tunnels for 72 h, dicamba volatility increased when soil pH decreased as the model predicted. Dicamba choline, which is not commercially available, had reduced volatility compared to other formulations tested. CONCLUSION: Results of this study identified specific factors that contribute to successful and unsuccessful dicamba applications and should be considered prior to applications.
PMID: 32385969
Plant Physiol Biochem , IF:3.72 , 2020 May , V152 : P62-71 doi: 10.1016/j.plaphy.2020.04.037
CO2 enrichment enhanced drought resistance by regulating growth, hydraulic conductivity and phytohormone contents in the root of cucumber seedlings.
College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China.; College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China; State Key Laboratory of Crop Biology, Taian, Shandong, 271018, China.; State Key Laboratory of Crop Biology, Taian, Shandong, 271018, China. Electronic address: lbroom@163.com.; College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China; State Key Laboratory of Crop Biology, Taian, Shandong, 271018, China; School of Environmental Sciences, University of Guelph, Guelph, ON, N1G 2W1, Canada. Electronic address: gslqm@sdau.edu.cn.
The coordinated effects of CO2 enrichment and drought stress on cucumber leaves have attracted increasing research attention, but few studies have investigated the effects of CO2 enrichment on the root system under drought stress. So we analyzed the morphological parameters, hydraulic conductivity, aquaporin-related gene expression, and endogenous phytohormone contents in roots of cucumber seedlings cultured under different CO2 concentrations (approximately 400 and 800 +/- 40 mumol mol(-1)) and drought stresses simulated by polyethylene glycol 6000 (0%, 5%, and 10%). The results showed that under drought stress, regardless of the CO2 concentration, the root biomass and hydraulic conductivity decreased, the contents of auxin (IAA), zeatin nucleoside (ZR), and gibberellin (GA) decreased, the abscisic acid (ABA) content and the transcript levels of the aquaporin-related genes CsPIP2-4 increased, and the transcript levels of the aquaporin-related genes CsPIP2-5 and CsPIP2-7 decreased compared with no drought stress. Under moderate drought stress, CO2 enrichment decreased ABA content and the transcript level of CsPIP2-4, increased root biomass and GA content and the transcript level of CsPIP2-7, improved contribution rate of cell-to-cell water transport (mediated by aquaporins) and roots hydraulic conductivity. In summary, drought stress changed the water transport capacity of the roots and inhibited the growth of cucumber seedlings. CO2 enrichment regulated phytohormone contents and aquaporin-related gene expression, maintained the normal contribution rate of cell-to-cell water transport, and improved the root biomass and hydraulic conductivity, thereby alleviated the negative effects of drought stress on cucumber seedlings.
PMID: 32388421
Plant Physiol Biochem , IF:3.72 , 2020 May , V150 : P209-221 doi: 10.1016/j.plaphy.2020.02.042
Gibberellins modulate shade-induced soybean hypocotyl elongation downstream of the mutual promotion of auxin and brassinosteroids.
College of Agronomy/Key Laboratory of Crop Eco-physiology and Farming System in Southwest China (Ministry of Agriculture), Sichuan Agricultural University, Chengdu, 611130, China.; College of Agronomy/Key Laboratory of Crop Eco-physiology and Farming System in Southwest China (Ministry of Agriculture), Sichuan Agricultural University, Chengdu, 611130, China. Electronic address: sunxin@sicau.edu.cn.; College of Agronomy/Key Laboratory of Crop Eco-physiology and Farming System in Southwest China (Ministry of Agriculture), Sichuan Agricultural University, Chengdu, 611130, China. Electronic address: junbodu@sicau.edu.cn.
Plants and crops are widely suffered by shade stress in the natural communities or in the agricultural fields. The three main phytohormones auxin, gibberellins (GAs) and brassinosteroids (BRs) were found essential in shade avoidance in Arabidopsis. However, their relationship have been seldom reported in plant shade avoidance control. Here, we report our investigation of the crosstalk of auxin, GAs and BRs in shade-induced hypocotyl elongation of soybean. Exogenous feeding of indol-3-acetic acid (IAA), GA3 or 24-epibrassinolide (EBL) distinctly promoted hypocotyl elongation in the white light, while the potent biosynthesis inhibitors of GA3, IAA, BRs severely diminished shade-induced hypocotyl elongation. Synergistic treatment of their biosynthesis inhibitors showed that GA3 fully, while EBL slightly, restored the hypocotyl elongation that was efficiently repressed by IAA biosynthesis inhibitor, GA3 and IAA dramatically suppressed the hypocotyl growth inhibition by BR biosynthesis inhibitor in the shade, whereas both IAA and EBL feeding cannot suppress the elongation inhibition by GA biosynthesis inhibitor. Further analyses revealed that shade remarkably upregulated expression of key genes of IAA, GA and BR biosynthesis in the soybean hypocotyls, and GA biosynthesis genes were effectively blocked by IAA, GA and BR biosynthesis inhibitors in the shade. Taken together, these results suggest that GAs modulate shade-induced hypocotyl elongation downstream of mutual promotion of auxin and BRs in soybean.
PMID: 32155449
Plant Physiol Biochem , IF:3.72 , 2020 May , V150 : P90-98 doi: 10.1016/j.plaphy.2020.02.034
Transcription factor WRKY23 is involved in ammonium-induced repression of Arabidopsis primary root growth under ammonium toxicity.
Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China; Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Provincial Key Laboratory of Nutrition in Common University, National Engineering Laboratory on Soil and Fertilizer Resources Efficient Utilization, Changsha, China.; National Center of Oilseed Crops Improvement, Hunan Branch, Changsha, China.; Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China; Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Provincial Key Laboratory of Nutrition in Common University, National Engineering Laboratory on Soil and Fertilizer Resources Efficient Utilization, Changsha, China. Electronic address: zhzh1468@163.com.
Although WRKY transcription factors (TFs) are known to be involved in the regulation of plant root development, the mechanisms by which these TFs regulate plant tolerance to ammonium (NH4(+)) toxicity remain unclear. To identify the molecular mechanisms underlying NH4(+)-induced repression of primary root growth and NH4(+) sensitivity in Arabidopsis, wild-type (Col-0) and mutant (wrky23) plants were treated with 10 mM KNO3 (control) or 5 mM (NH4)2SO4 (NH4(+) toxicity) for 7 days. Under NH4(+) toxicity, the fresh weight of wrky23 mutant was significantly lower than that of Col-0 plants, and the NH4(+) concentration in wrky23 roots was significantly higher than that in Col-0 roots. However, we observed no significant differences between the two genotypes under the control treatment. Ammonium transporter AMT1;2 expression was induced in wrky23 roots but not in Col-0 roots. The transcript levels of cytosolic glutamine synthetase-encoding genes and activity of glutamine synthetase did not differ significantly between wrky23 and Col-0. Furthermore, the fluorescence and staining patterns of DR5::GFP and DR5::GUS, respectively, were more pronounced under NH4(+) toxicity than under the control treatment. Collectively, our results indicate that AMT1;2 expression was induced in the wrky23 mutant in response to NH4(+) toxicity, leading to NH4(+) accumulation in the roots and primary root growth repression. Under NH4(+) toxicity, both auxin transport and distribution were affected, and auxin accumulation in the root tips inhibited primary root growth in the wrky23 mutant. Our study provides important insights into the molecular mechanisms by which WRKY23 TF regulates plant responses to NH4(+) toxicity.
PMID: 32135477
Plant Physiol Biochem , IF:3.72 , 2020 May , V150 : P15-26 doi: 10.1016/j.plaphy.2020.02.028
Auxin efflux carriers, MiPINs, are involved in adventitious root formation of mango cotyledon segments.
Key Laboratory of Tropical Fruit Biology, Ministry of Agriculture, South Subtropical Crop Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, 524091, China. Electronic address: liyunhe16@163.com.; College of Life Science, Shaoxing University, Shaoxing, 312000, China.; Key Laboratory of Tropical Fruit Biology, Ministry of Agriculture, South Subtropical Crop Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, 524091, China.
Adventitious roots form only at the proximal cut surface (PCS) but not at the distal cut surface (DCS) of mango cotyledon segments. In this study, mango embryos treated with indole-3-butyric acid (IBA) showed significantly increased adventitious root formation, while those treated with 2, 3, 5-triiodobenzoic acid (TIBA) demonstrated complete inhibition of adventitious rooting. Mango embryos treated with auxin influx inhibitors demonstrated lower inhibition of adventitious roots than those treated with TIBA. The endogenous indol-3-acetic acid (IAA) content on the PCS and DCS was similar at 0 h, then increased on both surfaces after 6 h, and IAA content on the PCS were always higher than those on the DCS. We cloned three genes encoding auxin efflux carriers (i.e., MiPIN2-4) and examined their temporal and spatial expression patterns under different treatments. Relative expression of all MiPINs studied was very low at 0 h but significantly increased on both PCS and DCS from 1 d to 10 d, to varying degrees. We overexpressed MiPIN1-4 in Arabidopsis plants and found a significant increase in adventitious root quantity in MiPIN1 and MiPIN3 transgenic lines. Immunofluorescence results showed that MiPIN1 and MiPIN3 are primarily localized in the vascular tissues and the cells adjacent to abaxial surface. In conclusion, we propose that in mango cotyledon segments, wounding stimulates IAA biosynthesis, the transcription levels of PIN genes were significantly increased in different magnitudes on the PCS and DCS, resulting in polar IAA transport from the DCS to PCS via the vascular tissues, thereby triggering adventitious root formation.
PMID: 32105796
Plant Sci , IF:3.591 , 2020 May , V294 : P110468 doi: 10.1016/j.plantsci.2020.110468
Salivary proteins of Phloeomyzus passerinii, a plant-manipulating aphid, and their impact on early gene responses of susceptible and resistant poplar genotypes.
Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRA, Universite d'Orleans, 45067, Orleans, France; Ecologie et Dynamique des Systemes Anthropises, EDYSAN UMR CNRS-UPJV 7058, Universite de Picardie Jules Verne, Amiens, France.; Ecologie et Dynamique des Systemes Anthropises, EDYSAN UMR CNRS-UPJV 7058, Universite de Picardie Jules Verne, Amiens, France.; Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS/Universite Francois-Rabelais de Tours, Tours, France.; Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRA, Universite d'Orleans, 45067, Orleans, France.; Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRA, Universite d'Orleans, 45067, Orleans, France. Electronic address: aurelien.salle@univ-orleans.fr.
Successful plant colonization by parasites requires the circumvention of host defenses, and sometimes a reprogramming of host metabolism, mediated by effector molecules delivered into the host. Using transcriptomic and enzymatic approaches, we characterized salivary glands and saliva of Phloeomyzus passerinii, an aphid exhibiting an atypical feeding strategy. Plant responses to salivary extracts of P. passerinii and Myzus persicae were assessed with poplar protoplasts of a susceptible and a resistant genotype, and in a heterologous Arabidopsis system. We predict that P. passerinii secretes a highly peculiar saliva containing effectors potentially interfering with host defenses, biotic stress signaling and plant metabolism, notably phosphatidylinositol phosphate kinases which seemed specific to P. passerinii. Gene expression profiles indicated that salivary extracts of M. persicae markedly affected host defenses and biotic stress signaling, while salivary extracts of P. passerinii induced only weak responses. The effector-triggered susceptibility was characterized by downregulations of genes involved in cytokinin signaling and auxin homeostasis. This suggests that P. passerinii induces an intracellular accumulation of auxin in susceptible host genotypes, which is supported by histochemical assays in Arabidopsis. This might in turn affect biotic stress signaling and contribute to host tissue manipulation by the aphid.
PMID: 32234233
BMC Plant Biol , IF:3.497 , 2020 May , V20 (1) : P232 doi: 10.1186/s12870-020-02448-7
A novel insight into nitrogen and auxin signaling in lateral root formation in tea plant [Camellia sinensis (L.) O. Kuntze].
College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.; College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.; Department of Plant Science, University of Manitoba, Winnipeg, R3T 2N2, Canada.; College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China. lxh@njau.edu.cn.
BACKGROUND: Tea plant (Camellia sinensis) is one of the most popular non-alcoholic beverages worldwide. In tea, lateral roots (LRs) are the main organ responsible for the absorption of moisture and mineral nutrients from the soil. Lateral roots formation and development are regulated by the nitrogen and auxin signaling pathways. In order to understand the role of auxin and nitrogen signaling in LRs formation and development, transcriptome analysis was employed to investigate the differentially expressed genes involved in lateral roots of tea plants treated with indole-3-butyric acid (IBA), N-1-naphthylphthalamic acid (NPA), low and high concentrations of nitrogen. RESULTS: A total of 296 common differentially expressed genes were identified and annotated to four signaling pathways, including nitrogen metabolism, plant hormone signal transduction, glutathione metabolism and transcription factors. RNA-sequencing results revealed that majority of differentially expressed genes play important roles in nitrogen metabolism and hormonal signal transduction. Low nitrogen condition induced the biosynthesis of auxin and accumulation of transcripts, thereby, regulating lateral roots formation. Furthermore, metabolism of cytokinin and ethylene biosynthesis were also involved in lateral roots development. Transcription factors like MYB genes also contributed to lateral roots formation of tea plants through secondary cell wall biosynthesis. Reversed phase ultra performance liquid chromatography (RP-UPLC) results showed that the auxin concentration increased with the decreased nitrogen level in lateral roots. Thus, tea plant lateral roots formation could be induced by low nitrogen concentration via auxin biosynthesis and accumulation. CONCLUSION: This study provided insights into the mechanisms associated with nitrogen and auxin signaling pathways in LRs formation and provides information on the efficient utilization of nitrogen in tea plant at the genetic level.
PMID: 32448156
Plant Mol Biol , IF:3.302 , 2020 May , V103 (1-2) : P197-210 doi: 10.1007/s11103-020-00984-2
AtDRO1 is nuclear localized in root tips under native conditions and impacts auxin localization.
Washington State University Tree Fruit Research and Extension Center, Wenatchee, WA, 98801, USA.; USDA-ARS Appalachian Fruit Research Station, Kearneysville, WV, 25430, USA.; USDA-ARS Appalachian Fruit Research Station, Kearneysville, WV, 25430, USA. chris.dardick@usda.gov.
DEEPER ROOTING 1 (DRO1) contributes to the downward gravitropic growth trajectory of roots upstream of lateral auxin transport in monocots and dicots. Loss of DRO1 function leads to horizontally oriented lateral roots and altered gravitropic set point angle, while loss of all three DRO family members results in upward, vertical root growth. Here, we attempt to dissect the roles of AtDRO1 by analyzing expression, protein localization, auxin gradient formation, and auxin responsiveness in the atdro1 mutant. Current evidence suggests AtDRO1 is predominantly a membrane-localized protein. Here we show that VENUS-tagged AtDRO1 driven by the native AtDRO1 promoter complemented an atdro1 Arabidopsis mutant and the protein was localized in root tips and detectable in nuclei. atdro1 primary and lateral roots showed impairment in establishing an auxin gradient upon gravistimulation as visualized with DII-VENUS, a sensor for auxin signaling and proxy for relative auxin distribution. Additionally, PIN3 domain localization was not significantly altered upon gravistimulation in atdro1 primary and lateral roots. RNA-sequencing revealed differential expression of known root development-related genes in atdro1 mutants. atdro1 lateral roots were able to respond to exogenous auxin and AtDRO1 gene expression levels in root tips were unaffected by the addition of auxin. Collectively, the data suggest that nuclear localization may be important for AtDRO1 function and suggests a more nuanced role for DRO1 in regulating auxin-mediated changes in lateral branch angle. KEY MESSAGE: DEEPER ROOTING 1 (DRO1) when expressed from its native promoter is predominately localized in Arabidopsis root tips, detectable in nuclei, and impacts auxin gradient formation.
PMID: 32130643
Plant Mol Biol , IF:3.302 , 2020 May , V103 (1-2) : P1-7 doi: 10.1007/s11103-020-00985-1
Homeostasis of histone acetylation is critical for auxin signaling and root morphogenesis.
NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam.; Department of Biotechnology, Institute of Biotechnology and Food-Technology, Industrial University of Ho Chi Minh City, 12 Nguyen Van Bao Street, Ward 4, Go Vap District, Ho Chi Minh City, Vietnam.; Faculty of Biotechnology, Ho Chi Minh City Open University, 97 Vo Van Tan Street, District 3, Ho Chi Minh City, Vietnam. nguyen.nhoai@ou.edu.vn.
KEY MESSAGE: The auxin signaling and root morphogenesis are harmoniously controlled by two counteracted teams including (1) auxin/indole-3-acetic acid (AUX/IAA)-histone deacetylase (HDA) and (2) auxin response factor (ARF)-histone acetyltransferase (HAT). The involvement of histone acetylation in the regulation of transcription was firstly reported a few decades ago. In planta, auxin is the first hormone group that was discovered and it is also the most studied phytohormone. Current studies have elucidated the functions of histone acetylation in the modulation of auxin signaling as well as in the regulation of root morphogenesis under both normal and stress conditions. Based on the recent outcomes, this review is to provide a hierarchical view about the functions of histone acetylation in auxin signaling and root morphogenesis. In this report, we suggest that the auxin signaling must be controlled harmoniously by two counteracted teams including (1) auxin/indole-3-acetic acid (AUX/IAA)-histone deacetylase (HDA) and (2) auxin response factor (ARF)-histone acetyltransferase (HAT). Moreover, the balance in auxin signaling is very critical to contribute to normal root morphogenesis.
PMID: 32088831
Plant Mol Biol , IF:3.302 , 2020 May , V103 (1-2) : P113-128 doi: 10.1007/s11103-020-00978-0
Time-course RNA-seq analysis provides an improved understanding of gene regulation during the formation of nodule-like structures in rice.
Department of Biology, University of Central Arkansas, Conway, AR, 72035, USA.; Bioinformatics and Biostatistics Core, Van Andel Research Institute, Grand Rapids, MI, 49503, USA.; Department of Biology, University of Central Arkansas, Conway, AR, 72035, USA. amukherjee@uca.edu.
KEY MESSAGE: Using a time-course RNA-seq analysis we identified transcriptomic changes during formation of nodule-like structures (NLS) in rice and compared rice RNA-seq dataset with a nodule transcriptome dataset in Medicago truncatula. Plant hormones can induce the formation of nodule-like structures (NLS) in plant roots even in the absence of bacteria. These structures can be induced in roots of both legumes and non-legumes. Moreover, nitrogen-fixing bacteria can recognize and colonize these root structures. Therefore, identifying the genetic switches controlling the NLS organogenesis program in crops, especially cereals, can have important agricultural implications. Our recent study evaluated the transcriptomic response occurring in rice roots during NLS formation, 7 days post-treatment (dpt) with auxin, 2,4-D. In this current study, we investigated the regulation of gene expression occurring in rice roots at different stages of NLS formation: early (1-dpt) and late (14-dpt). At 1-dpt and 14-dpt, we identified 1662 and 1986 differentially expressed genes (DEGs), respectively. Gene ontology enrichment analysis revealed that the dataset was enriched with genes involved in auxin response and signaling; and in anatomical structure development and morphogenesis. Next, we compared the gene expression profiles across the three time points (1-, 7-, and 14-dpt) and identified genes that were uniquely or commonly differentially expressed at all three time points. We compared our rice RNA-seq dataset with a nodule transcriptome dataset in Medicago truncatula. This analysis revealed there is some amount of overlap between the molecular mechanisms governing nodulation and NLS formation. We also identified that some key nodulation genes were not expressed in rice roots during NLS formation. We validated the expression pattern of several genes via reverse transcriptase polymerase chain reaction (RT-PCR). The DEGs identified in this dataset may serve as a useful resource for future studies to characterize the genetic pathways controlling NLS formation in cereals.
PMID: 32086696
Plant Mol Biol , IF:3.302 , 2020 May , V103 (1-2) : P91-111 doi: 10.1007/s11103-020-00977-1
Auxin treatment of grapevine (Vitis vinifera L.) berries delays ripening onset by inhibiting cell expansion.
Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy.; School of Agriculture, Food and Wine, Level 4, Main WIC Building, University of Adelaide, Waite Campus, Urrbrae, SA, 5064, Australia.; CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA, 5064, Australia.; E. & J. Gallo Winery, 600 Yosemite Blvd, Modesto, CA, 95354, USA.; CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA, 5064, Australia. christopher.davies@csiro.au.
KEY MESSAGE: Auxin treatment of grape (Vitis vinifera L.) berries delays ripening by inducing changes in gene expression and cell wall metabolism and could combat some deleterious climate change effects. Auxins are inhibitors of grape berry ripening and their application may be useful to delay harvest to counter effects of climate change. However, little is known about how this delay occurs. The expression of 1892 genes was significantly changed compared to the control during a 48 h time-course where the auxin 1-naphthaleneacetic acid (NAA) was applied to pre-veraison grape berries. Principal component analysis showed that the control and auxin-treated samples were most different at 3 h post-treatment when approximately three times more genes were induced than repressed by NAA. There was considerable cross-talk between hormone pathways, particularly between those of auxin and ethylene. Decreased expression of genes encoding putative cell wall catabolic enzymes (including those involved with pectin) and increased expression of putative cellulose synthases indicated that auxins may preserve cell wall structure. This was confirmed by immunochemical labelling of berry sections using antibodies that detect homogalacturonan (LM19) and methyl-esterified homogalacturonan (LM20) and by labelling with the CMB3a cellulose-binding module. Comparison of the auxin-induced changes in gene expression with the pattern of these genes during berry ripening showed that the effect on transcription is a mix of changes that may specifically alter the progress of berry development in a targeted manner and others that could be considered as non-specific changes. Several lines of evidence suggest that cell wall changes and associated berry softening are the first steps in ripening and that delaying cell expansion can delay ripening providing a possible mechanism for the observed auxin effects.
PMID: 32043226
Gene , IF:2.984 , 2020 May , V738 : P144460 doi: 10.1016/j.gene.2020.144460
Identification of miR390-TAS3-ARF pathway in response to salt stress in Helianthus tuberosus L.
College of Resources and Environmental Sciences/ Jiangsu Provincial Key Laboratory of Marine Biology, Nanjing Agricultural University, Nanjing 210095, China.; College of Resources and Environmental Sciences/ Jiangsu Provincial Key Laboratory of Marine Biology, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: zszhou@njau.edu.cn.; College of Resources and Environmental Sciences/ Jiangsu Provincial Key Laboratory of Marine Biology, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: longxiaohua@njau.edu.cn.
MicroRNA390 (miR390), an ancient and highly conserved miRNA family in land plants, plays multiple roles in plant growth, development and stress responses. In this study, we isolated and identified MIR390, miR390, TAS3a/b/c, tasiARF-1/2/3 (trans-acting small interfering RNAs influencing Auxin Response Factors) and ARF2/3/4 in Jerusalem artichoke (Helianthus tuberosus L.). Treatment with 100 mM NaCl induced expression of miR390, increased cleavage of TAS3, produced high levels of tasiARFs, and subsequently enhanced cleavage of ARF3/4, which was most likely associated with salt tolerance of the plants. In contrast, treatment with 300 mM NaCl inhibited expression of miR390, attenuated cleavage of TAS3, produced a small amount of tasiARFs, and reduced cleavage of ARF3/4. We proposed that ARF2, one of the targets of tasiARFs, induced under salinity was likely to play an active role in salt tolerance of Jerusalem artichoke. The study of the miR390-TAS3-ARF model in Jerusalem artichoke may broaden our understanding of salt tolerance mechanisms, and provides a theoretical support for further genetic identification and breeding crops with increased tolerance to salt stress.
PMID: 32045659
Plants (Basel) , IF:2.762 , 2020 May , V9 (5) doi: 10.3390/plants9050630
Variation of Growth-to-Ripening Time Interval Induced by Abscisic Acid and Synthetic Auxin Affecting Transcriptome and Flavor Compounds in Cabernet Sauvignon Grape Berry.
Center for Viticulture & Enology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.; Key Laboratory of Viticulture and Enology, Ministry of Agriculture and Rural Affairs, Beijing 100083, China.; College of Food Science and Engineering, Shanxi Agriculture University, Jinzhong, Shanxi 030801, China.
Abscisic acid (ABA) and auxin are important hormones controlling the ripening progression of grape berry, and both the initiation and duration of ripening can dramatically affect the berry quality. However, the responses of flavor compounds to the hormones are inadequately understood. In this study, ABA and synthetic auxin alpha-naphthaleneacetic acid (NAA) were sprayed on Cabernet Sauvignon berries before veraison, and comparative transcriptomic and metabolic analysis were conducted to investigate the influence on berry quality-related metabolites. The 1000 mg/L ABA (ABA1000) and 200 mg/L NAA (NAA200) treated grapes exhibited shorter and longer phenological intervals compared to the control, respectively. The transcriptomic comparison between pre-veraison and veraison revealed that the varied ripening initiation and duration significantly affected the expression of genes related to specific metabolism, particularly in the biosynthetic metabolism of anthocyanin and volatile compounds. The up-regulated VviF3'H in both ABA1000-treated and NAA200-treated berries increased the proportion of 3'-substituted anthocyanins, and the 3'5'-substituted anthocyanins were largely reduced in the NAA200-treated berries. Concurrently, VviCCD4a and VviCCD4b were up-regulated, and the norisoprenoids were correspondingly elevated in the NAA200-treated berries. These data suggest that ABA and NAA applications may be useful in controlling the ripening and improving the flavor of the grape berry.
PMID: 32423087
Plants (Basel) , IF:2.762 , 2020 May , V9 (5) doi: 10.3390/plants9050610
A Role for Auxin in Ethylene-Dependent Inducible Aerenchyma Formation in Rice Roots.
Japan Science and Technology Agency, PRESTO, Kawaguchi, Saitama 332-0012, Japan.; Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.; Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.; International Center for Research and Education in Agriculture, Nagoya University, Nagoya, Aichi 464-8601, Japan.; The UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, WA 6009, Australia.
Internal oxygen diffusion from shoot to root tips is enhanced by the formation of aerenchyma (gas space) in waterlogged soils. Lysigenous aerenchyma is created by programmed cell death and subsequent lysis of the root cortical cells. Rice (Oryza sativa) forms aerenchyma constitutively under aerobic conditions and increases its formation under oxygen-deficient conditions. Recently, we have demonstrated that constitutive aerenchyma formation is regulated by auxin signaling mediated by Auxin/indole-3-acetic acid protein (AUX/IAA; IAA). While ethylene is involved in inducible aerenchyma formation, the relationship of auxin and ethylene during aerenchyma formation remains unclear. Here, we examined the effects of oxygen deficiency and ethylene on aerenchyma formation in the roots of a rice mutant (iaa13) in which auxin signaling is suppressed by a mutation in the degradation domain of IAA13 protein. The results showed that AUX/IAA-mediated auxin signaling contributes to ethylene-dependent inducible aerenchyma formation in rice roots. An auxin transport inhibitor abolished aerenchyma formation under oxygen-deficient conditions and reduced the expression of genes encoding ethylene biosynthesis enzymes, further supporting the idea that auxin is involved in ethylene-dependent inducible aerenchyma formation. Based on these studies, we propose a mechanism that underlies the relationship between auxin and ethylene during inducible aerenchyma formation in rice roots.
PMID: 32403344
Protoplasma , IF:2.751 , 2020 May , V257 (3) : P979-992 doi: 10.1007/s00709-020-01484-2
Genome-wide characterization and expression analysis of the auxin response factor (ARF) gene family during melon (Cucumis melo L.) fruit development.
Beijing Key Laboratory for Agricultural Application and New Technology, National Demonstration Center for Experimental Plant Production Education, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, 102206, China.; Beijing Agricultural Technology Extension Station, Beijing, 100029, China.; Agricultural and Rural Bureau of Jing County of Hebei Province, Hebei, 053500, China.; Beijing Key Laboratory for Agricultural Application and New Technology, National Demonstration Center for Experimental Plant Production Education, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, 102206, China. haojinghong2013@126.com.
ARFs in plants mediate auxin signaling transduction and regulate growth process. To determine genome-wide characterization of ARFs family in melon (Cucumis melo L.), ARFs were identified via analysis of information within the melon genomic database, and bioinformatic analyses were performed using various types of software. Based on different treatment methods involving dipping with the growth regulator Fengchanji No. 2 and artificial pollination, Jingmi No. 11 melon was used as the test material, and melon plants with unpollinated ovaries served as controls. The expression of ARFs during the early development of melon was analyzed via qRT-PCR. Seventeen genes that encode ARF proteins were identified in the melon genome for the first time. The expression of these ARFs differed in different tissues. The expression levels of CmARF2, CmARF16-like, CmARF18-like2, and CmARF19-like were especially high in melon fruits. The expression of ARFs during the early development of melon fruits differed in response to the different treatments, which suggested that CmARF9, CmARF16-like, CmARF19-like, CmARF19, CmARF1, CmARF2, CmARF3, and CmARF5 may be associated with melon fruit growth during early development. Interestingly, the increase in the transverse diameter of fruits treated with growth regulators was significantly greater than that of fruits resulting from artificial pollination, while the increase in the longitudinal diameter of the fruits resulting from artificial pollination was significantly greater.
PMID: 32043172
J Plant Res , IF:2.185 , 2020 May , V133 (3) : P409-417 doi: 10.1007/s10265-020-01183-2
DORMANCY/AUXIN ASSOCIATED FAMILY PROTEIN 2 of Arabidopsis thaliana is a negative regulator of local and systemic acquired resistance.
415, School of Life Science, Jawaharlal Nehru University, New Delhi, 110067, India.; 415, School of Life Science, Jawaharlal Nehru University, New Delhi, 110067, India. ashis_nandi@yahoo.com.
To fine tune defense response output, plants recruit both positive and negative regulators. Here we report Arabidopsis DORMANCY/AUXIN ASSOCIATED FAMILY PROTEIN 2(DAP2) gene as a negative regulator of basal defense against virulent bacterial pathogens. Expression of DAP2 enhances upon pathogen inoculation. Our experiments show that DAP2 suppressed resistance against virulent strains of bacterial pathogens, pathogen-induced callose deposition, and ROS accumulation; however, it did not influence effector-triggered immunity. In addition, DAP2 negatively regulated systemic acquired resistance (SAR). DAP2 expression was enhanced in the pathogen-free systemic tissues of SAR-induced plants. Previously, Arabidopsis Flowering locus D (FLD) gene has been shown to be essential for SAR but not for local resistance. We show here that FLD function is necessary for SAR-induced expression of DAP2, suggesting DAP2 as a target of FLD for activation of SAR in Arabidopsis.
PMID: 32227262
Plant Direct , IF:1.725 , 2020 May , V4 (5) : Pe00217 doi: 10.1002/pld3.217
FaPAO5 regulates Spm/Spd levels as a signaling during strawberry fruit ripening.
Beijing Collaborative Innovation Center for Eco-Environmental Improvement with Forestry and Fruit Trees Beijing University of Agriculture Beijing China.; Bei Jing Bei Nong Enterprise Management Co., Ltd Beijing China.
Polyamines are important for non-climacteric fruit ripening according to an analysis of the model plant strawberry. However, the molecular mechanism underlying the polyamine accumulation during ripening has not been fully elucidated. In this study, an examination of our proteome data related to strawberry fruit ripening revealed a putative polyamine oxidase 5, FaPAO5, which was localized in the cytoplasm and nucleus. Additionally, FaPAO5 expression levels as well as the abundance of the encoded protein continually decreased during ripening. Inhibiting FaPAO5 expression by RNAi promoted Spd, Spm, and ABA accumulation while inhibited H2O2 production, which ultimately enhanced ripening as evidenced by the ripening-related events and corresponding gene expression changes. The opposite effects were observed in FaPAO5-overexpressing transgenic fruits. Analyses of the binding affinity and enzymatic activity of FaPAO5 with Spm, Spd, and Put uncovered a special role for FaPAO5 in the terminal catabolism of Spm and Spd, with a K d of 0.21 and 0.29 microM, respectively. Moreover, FaPAO5 expression was inhibited by ABA and promoted by Spd and Spm. Furthermore, the RNA-seq analysis of RNAi and control fruits via differentially expressed genes (DEGs) indicated the six most enriched pathways among the differentially expressed genes were related to sugar, abscisic acid, ethylene, auxin, gibberellin, and Ca(2+). Among four putative PAO genes in the strawberry genome, only FaPAO5 was confirmed to influence fruit ripening. In conclusion, FaPAO5 is a negative regulator of strawberry fruit ripening and modulates Spm/Spd levels as a signaling event, in which ABA plays a central role.
PMID: 32355906
Plant Signal Behav , IF:1.671 , 2020 May , V15 (5) : P1748283 doi: 10.1080/15592324.2020.1748283
Roles and mechanisms of Ca(2+) in regulating primary root growth of plants.
State Key Laboratory of Cotton Biology, Henan Key Laboratory of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, China.
Calcium (Ca(2+)) as a universal signal molecule plays pivotal roles in plant growth and development. It regulates root morphogenesis mainly through mediating phytohormone and stress signalings or affecting these signalings. In recent years, much progress has been made in understanding the roles of Ca(2+) in primary root development. Here, we summarize recent advances in the functions and mechanisms of Ca(2+) in modulating primary root growth in plants under normal and stressful conditions.
PMID: 32264747
Plant Signal Behav , IF:1.671 , 2020 May , V15 (5) : P1744373 doi: 10.1080/15592324.2020.1744373
MicroRNA160 regulates leaf curvature in potato (Solanum tuberosum L. cv. Desiree).
Biology Division, Indian Institute of Science Education and Research (IISER Pune), Pune, India.
Leaf development is a complex process and factors such as size, shape, curvature, compounding, and texture determine the final leaf morphology. MicroRNA160 is one of the crucial players that has been shown to regulate lamina formation and compounding in tomato. In this study, we show that miR160 also regulates leaf curvature in potato. miR160 targets a group of Auxin Response Factors - StARF10, StARF16, and StARF17 - that are proposed to function majorly as repressors of auxin signaling. We observed that overexpression of miR160 (miR160-OE) results in decrease in the levels of these ARFs along with hypersensitivity to exogenous auxin treatment, whereas knockdown of miR160 (miR160-KD) causes increased ARF levels and auxin hyposensitivity. The leaves of miR160-OE plants have a high positive curvature, but of miR160-KD plants are flattened compared to wildtype. A prolonged activation of cell cycle - as indicated by increased levels of StCYCLIND3;2 - in the center region of miR160-OE leaves appears to have caused this positive curvature. However, a comparable StTCP4 activity at both center and margin regions of miR160-KD leaves could be the cause for its flattened leaf phenotype. In summary, we show that miR160 plays an important role in regulating leaf curvature in potato plants.
PMID: 32233909
Plant Signal Behav , IF:1.671 , 2020 May , V15 (5) : P1744294 doi: 10.1080/15592324.2020.1744294
Isolation, characterization, and plant growth-promoting activities of endophytic fungi from a wild orchid Vanda cristata.
Central Department of Botany, Tribhuvan University, Kritipur, Nepal.; Department of Plant Science, Texas Tech University, Lubbock, USA.
Endophytism is one of the widely explored phenomena related to orchids and fungi. Endophytic fungi assist plants by supplementing nutrient acquisition, and synthesis of plant growth regulators. Vanda cristata is an epiphytic orchid that has a great diversity of endophytic fungi. Endophytic fungi were isolated from roots, stems, and leaves of V. cristata and identified by both morphological and molecular study. Furthermore, the isolated endophytic fungi were subjected to auxin synthesis, phosphate solubilization, ammonia synthesis, and elicitor growth test for understanding their growth-promoting effect in a qualitative and quantitative manner. Altogether, 12 different endophytic fungi were isolated from roots, stems, and leaves of V. cristata of which most species belonged to Ascomycota. Unidentified II fungi were found to be most effective for auxin synthesis and phosphate solubilization while Agaricus bisporous and Mycolepto discus were most effective for ammonia synthesis. We have tested the plant growth-promoting activity of the twelve isolated endophytic fungi on Cymbidium aloifolium protocorms (12 weeks old). All the endophytic fungi showed growth-promoting activity. Plant growth of Cymbidium aloifolium was found higher on the MS medium supplemented with all fungal elicitors. Fungal elicitor CVS4, however, showed the highest plant growth-promoting activity toward C. aloifolium.
PMID: 32208892
Plant Signal Behav , IF:1.671 , 2020 May , V15 (5) : P1746510 doi: 10.1080/15592324.2020.1746510
Abscisic acid suppresses thermomorphogenesis in Arabidopsis thaliana.
College of Life Sciences, Nanjing Normal University, Nanjing, China.
Arabidopsis thaliana seedlings exhibit longer hypocotyls when they are grown under high ambient temperature, which is defined as thermomorphogenesis. Although it is well established that high temperature triggers auxin biosynthesis to stimulate hypocotyl elongation, the physiological functions of other endogenous phytohormones during thermomorphogenesis are still elusive. Here, we report that exogenous application of abscisic acid (ABA) strongly inhibits hypocotyl elongation under high ambient temperature. Hypocotyl elongations of ABA biosynthesis deficient mutants are more sensitive to high temperature, suggesting that endogenous ABA has a robust inhibition effect. Moreover, blocking ABA perception or signaling impedes the negative effect of ABA. Finally, we show that ABA also suppresses the hypersensitivity to high temperature of an auxin over-accumulation mutant (yuc1D), indicating that activation of auxin signaling is not sufficient to override the repression by ABA. Taken together, we demonstrate that ABA is a negative regulator during plant thermomorphogenesis.
PMID: 32202470
Mol Biol Rep , IF:1.402 , 2020 May , V47 (5) : P3885-3907 doi: 10.1007/s11033-020-05477-5
Genome-wide identification, characterization analysis and expression profiling of auxin-responsive GH3 family genes in wheat (Triticum aestivum L.).
Hubei Collaborative Innovation Center for Grain Industry/Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education/Forewarning and Management of Agricultural and Forestry Pests, Hubei Engineering Technology Center/College of Agriculture, Yangtze University, Jingzhou, Hubei, China.; Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China.; Institute of Plant Protection, Sichuan Academy of Agricultural Sciences/Key Laboratory of Integrated Pest Management of Crop in Southwest China, Ministry of Agriculture, Chengdu, Sichuan, China.; Hubei Collaborative Innovation Center for Grain Industry/Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education/Forewarning and Management of Agricultural and Forestry Pests, Hubei Engineering Technology Center/College of Agriculture, Yangtze University, Jingzhou, Hubei, China. madf@yangtzeu.edu.cn.; Institute of Plant Protection, Sichuan Academy of Agricultural Sciences/Key Laboratory of Integrated Pest Management of Crop in Southwest China, Ministry of Agriculture, Chengdu, Sichuan, China. madf@yangtzeu.edu.cn.; Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China. huaigu@jaas.ac.cn.
Auxin affects many aspects of plant growth and development by regulating the expression of auxin-responsive genes. As one of the three major auxin-responsive families the Gretchen Hagen3 (GH3) gene family maintains hormonal homeostasis by conjugating excess indole-3-acetic acid (IAA), salicylic acid (SA), and jasmonic acid (JA) to amino acids during hormone and stress-related signaling. Although some work has been carried out the functions of wheat GH3 (TaGH3) family genes in response to abiotic stresses (including salt stress and osmotic stress) are largely unknown. Access to the complete wheat genome sequence permits genome-wide studies on TaGH3s. We performed a systematic identification of the TaGH3 gene family at the genome level and detected 36 members on 14 wheat chromosomes. Many of the genes were segmentally duplicated and Ka/Ks and inter-species synthetic analyses indicated that polyploidization was the contributor to the increased number of TaGH3 members. Phylogenetic analyses revealed that TaGH3 proteins could divided into three major categories (TaGH3-I, TaGH3-II, and TaGH3-III). Diversified cis-elements in the promoters of TaGH3 genes were predicted as essential players in regulating TaGH3 expression patterns. Gene structure and motif analyses indicated that most TaGH3 genes have relatively conserved exon/intron arrangements and motif compositions. Analysis of multiple transcriptome data sets indicated that many TaGH3 genes are responsive to biological and abiotic stresses and possibly have important functions in stress response. qRT-PCR analysis revealed that TaGH3s were induced by salt and osmotic stresses. Customized annotation results revealed that TaGH3s were widely involved in phytohormone response, defense, growth and development, and metabolism. Overall, our work provides a comprehensive insight into the TaGH3 family members, and a basis for the further study of their biological functions in wheat.
PMID: 32361896
Zhejiang Da Xue Xue Bao Yi Xue Ban , 2020 May , V49 (1) : P1-19
[Targeting Cullin-RING E3 ligases for anti-cancer therapy: efforts on drug discovery].
Cancer Institute, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China.; Department of Translational Medicine, Zhejiang University, Hangzhou 310029, China.
Cullin-RING E3 ligases (CRLs) are the major components of ubiquitin-proteasome system, responsible for ubiquitylation and subsequent degradation of thousands of cellular proteins. CRLs play vital roles in the regulation of multiple cellular processes, including cell cycle, cell apoptosis, DNA replication, signalling transduction among the others, and are frequently dysregulated in many human cancers. The discovery of specific neddylation inhibitors, represented by MLN4924, has validated CRLs as promising targets for anti-cancer therapies with a growing market. Recent studies have focused on the discovery of the CRLs inhibitors by a variety of approaches, including high through-put screen, virtual screen or structure-based drug design. The field is, however, still facing the major challenging, since CRLs are a large multi-unit protein family without typical active pockets to facilitate the drug design, and enzymatic activity is mainly dependent on undruggable protein-protein interactions and dynamic conformation changes. Up to now, most reported CRLs inhibitors are aiming at targeting the F-box family proteins (e.g., SKP2, beta-TrCP and FBXW7), the substrate recognition subunit of SCF E3 ligases. Other studies reported few small molecule inhibitors targeting the UBE2M-DCN1 interaction, which specifically inhibits CRL3/CRL1 by blocking the cullin neddylation. On the other hand, several CRL activators have been reported, such as plant auxin and immunomodulatory imide drugs, thalidomide. Finally, proteolysis-targeting chimeras (PROTACs) has emerged as a new technology in the field of drug discovery, specifically targeting the undruggable protein-protein interaction. The technique connects the small molecule that selectively binds to a target protein to a CRL E3 via a chemical linker to trigger the degradation of target protein. The PROTAC has become a hotspot in the field of E3-ligase-based anti-cancer drug discovery.
PMID: 32621419