Nat Plants , IF:13.256 , 2021 Mar , V7 (3) : P353-364 doi: 10.1038/s41477-021-00862-9
GDSL-domain proteins have key roles in suberin polymerization and degradation.
Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland. Robertas.Ursache@unil.ch.; Laboratory of Cell and Molecular Biology, Institute of Biology, University of Neuchatel, Neuchatel, Switzerland.; Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland.; Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland.; Vital-IT Competence Center, Swiss Institute of Bioinformatics, Lausanne, Switzerland.; NGSAI, Epalinges, Switzerland.; Max Planck Institute for Plant Breeding Research, Cologne, Germany.; Department of Plant and Microbial Biology & Zurich-Basel Plant Science Centre, University of Zurich, Zurich, Switzerland.; Genomic Technologies Facility, University of Lausanne, Lausanne, Switzerland.; Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland. Niko.Geldner@unil.ch.; Laboratory of Cell and Molecular Biology, Institute of Biology, University of Neuchatel, Neuchatel, Switzerland. Josephus.Vermeer@unine.ch.; Department of Plant and Microbial Biology & Zurich-Basel Plant Science Centre, University of Zurich, Zurich, Switzerland. Josephus.Vermeer@unine.ch.
Plant roots acquire nutrients and water while managing interactions with the soil microbiota. The root endodermis provides an extracellular diffusion barrier through a network of lignified cell walls called Casparian strips, supported by subsequent formation of suberin lamellae. Whereas lignification is thought to be irreversible, suberin lamellae display plasticity, which is crucial for root adaptative responses. Although suberin is a major plant polymer, fundamental aspects of its biosynthesis and turnover have remained obscure. Plants shape their root system via lateral root formation, an auxin-induced process requiring local breaking and re-sealing of endodermal lignin and suberin barriers. Here, we show that differentiated endodermal cells have a specific, auxin-mediated transcriptional response dominated by cell wall remodelling genes. We identified two sets of auxin-regulated GDSL lipases. One is required for suberin synthesis, while the other can drive suberin degradation. These enzymes have key roles in suberization, driving root suberin plasticity.
PMID: 33686223
Nat Ecol Evol , IF:12.541 , 2021 Mar doi: 10.1038/s41559-021-01406-2
Eco-evolutionary interaction between microbiome presence and rapid biofilm evolution determines plant host fitness.
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA. jtan7@lsu.edu.; Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA. jtan7@lsu.edu.; Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA.
Microbiomes are important to the survival and reproduction of their hosts. Although ecological and evolutionary processes can happen simultaneously in microbiomes, little is known about how microbiome eco-evolutionary dynamics determine host fitness. Here we show, using experimental evolution, that fitness of the aquatic plant Lemna minor is modified by interactions between the microbiome and the evolution of one member, Pseudomonas fluorescens. Microbiome presence promotes P. fluorescens' rapid evolution to form biofilm, which reciprocally alters the microbiome's species composition. These eco-evolutionary dynamics modify the host's multigenerational fitness. The microbiome and non-evolving P. fluorescens together promote host fitness, whereas the microbiome with P. fluorescens that evolves biofilm reduces the beneficial impact on host fitness. Additional experiments suggest that the microbial effect on host fitness may occur through changes in microbiome production of auxin, a plant growth hormone. Our study, therefore, experimentally demonstrates the importance of the eco-evolutionary dynamics in microbiomes for host-microbiome interactions.
PMID: 33707690
Nat Commun , IF:12.121 , 2021 Mar , V12 (1) : P1657 doi: 10.1038/s41467-021-21802-3
Cell kinetics of auxin transport and activity in Arabidopsis root growth and skewing.
School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel.; Section of Cell and Developmental Biology, University of California, San Diego, San Diego, CA, USA.; Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel.; Institute of Science and Technology Austria, Klosterneuburg, Austria.; The Key Laboratory of Plant Development and Environmental Adaptation Biology, Shandong University, Qingdao, Shandong, China.; Section of Cell and Developmental Biology, University of California, San Diego, San Diego, CA, USA. yundezhao@ucsd.edu.; Department of Clinical Microbiology and Immunology, Tel Aviv University, Tel Aviv, Israel. ilants@tauex.tau.ac.il.; School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel. eilonsh@tauex.tau.ac.il.
Auxin is a key regulator of plant growth and development. Local auxin biosynthesis and intercellular transport generates regional gradients in the root that are instructive for processes such as specification of developmental zones that maintain root growth and tropic responses. Here we present a toolbox to study auxin-mediated root development that features: (i) the ability to control auxin synthesis with high spatio-temporal resolution and (ii) single-cell nucleus tracking and morphokinetic analysis infrastructure. Integration of these two features enables cutting-edge analysis of root development at single-cell resolution based on morphokinetic parameters under normal growth conditions and during cell-type-specific induction of auxin biosynthesis. We show directional auxin flow in the root and refine the contributions of key players in this process. In addition, we determine the quantitative kinetics of Arabidopsis root meristem skewing, which depends on local auxin gradients but does not require PIN2 and AUX1 auxin transporter activities. Beyond the mechanistic insights into root development, the tools developed here will enable biologists to study kinetics and morphology of various critical processes at the single cell-level in whole organisms.
PMID: 33712581
Mol Plant , IF:12.084 , 2021 Mar doi: 10.1016/j.molp.2021.03.011
A crosstalk between auxin and brassinosteroid regulates leaf shape by modulating growth anisotropy.
State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.; State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China.; Beijing International Center for Mathematical Research, Peking University, Beijing 100871, China.; Key Laboratory of Microgravity (National Microgravity Laboratory), Center of Biomechanics and Bioengineering, and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China; School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China.; Beijing International Center for Mathematical Research, Peking University, Beijing 100871, China. Electronic address: yljiao@genetics.ac.cn.; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: yljiao@genetics.ac.cn.; State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: yljiao@genetics.ac.cn.
Leaf shape is highly variable within and among plant species, ranging from slender to oval-shaped. This is largely determined by the proximodistal axis of growth. However, little is known about how proximal-distal growth is controlled to determine leaf shape. Here, we show that Arabidopsis leaf and sepal proximodistal growth is tuned by two phytohormones. Two class A AUXIN RESPONSE FACTORs (ARFs), ARF6 and ARF8, activate the transcription of DWARF4, which encodes a key brassinosteroid (BR) biosynthetic enzyme. At the cellular level, the phytohormones promote more directional cell expansion along the proximodistal axis, as well as final cell sizes. BRs promote the demethyl-esterification of cell wall pectins, leading to isotropic in-plane cell wall loosening. Notably, numerical simulation showed that isotropic cell wall loosening could lead to directional cell and organ growth along the proximodistal axis. Taken together, we show that auxin acts through BRs biosynthesis to determine cell wall mechanics and directional cell growth to generate leaves of variable roundness.
PMID: 33722761
Mol Plant , IF:12.084 , 2021 Mar doi: 10.1016/j.molp.2021.03.008
The lncRNA APOLO interacts with the transcription factor WRKY42 to trigger root hair cell expansion in response to cold.
Instituto de Agrobiotecnologia del Litoral, Universidad Nacional del Litoral, CONICET, FBCB/FHUC, Centro Cientifico Tecnologico CONICET Santa Fe, Colectora Ruta Nacional No 168 km. 0, Paraje El Pozo, Santa Fe 3000, Argentina.; Fundacion Instituto Leloir and IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires CP C1405BWE, Argentina.; Instituto de Investigaciones Agrobiotecnologicas, CONICET, Universidad Nacional de Rio Cuarto, Rio Cuarto 5800, Argentina.; Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Saclay and University of Paris Batiment 630, 91192 Gif sur Yvette, France.; Fundacion Instituto Leloir and IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires CP C1405BWE, Argentina; Centro de Biotecnologia Vegetal (CBV), Facultad de Ciencias de la Vida (FCsV), Universidad Andres Bello, Santiago, Chile and Millennium Institute for Integrative Biology (iBio), Santiago, Chile. Electronic address: fariel@santafe-conicet.gov.ar.; Instituto de Agrobiotecnologia del Litoral, Universidad Nacional del Litoral, CONICET, FBCB/FHUC, Centro Cientifico Tecnologico CONICET Santa Fe, Colectora Ruta Nacional No 168 km. 0, Paraje El Pozo, Santa Fe 3000, Argentina. Electronic address: fariel@santafe-conicet.gov.ar.
Plant long noncoding RNAs (lncRNAs) have emerged as important regulators of chromatin dynamics, impacting on transcriptional programs leading to different developmental outputs. The lncRNA AUXIN REGULATED PROMOTER LOOP (APOLO) directly recognizes multiple independent loci across the Arabidopsis genome and modulates their three-dimensional chromatin conformation, leading to transcriptional shifts. Here, we show that APOLO recognizes the locus encoding the root hair (RH) master regulator ROOT HAIR DEFECTIVE 6 (RHD6) and controls RHD6 transcriptional activity leading to cold-enhanced RH elongation through the consequent activation of the transcription factor gene RHD6-like RSL4. Furthermore, we demonstrate that APOLO interacts with the transcription factor WRKY42 and modulates its binding to the RHD6 promoter. WRKY42 is required for the activation of RHD6 by low temperatures and WRKY42 deregulation impairs cold-induced RH expansion. Collectively, our results indicate that a novel ribonucleoprotein complex involving APOLO and WRKY42 forms a regulatory hub which activates RHD6 by shaping its epigenetic environment and integrates signals governing RH growth and development.
PMID: 33689931
Biol Rev Camb Philos Soc , IF:10.701 , 2021 Mar doi: 10.1111/brv.12699
The stele - a developmental perspective on the diversity and evolution of primary vascular architecture.
Department of Biological Sciences, Humboldt State University, Arcata, CA, 95521, U.S.A.
The stele concept is one of the oldest enduring concepts in plant biology. Here, I review the history of the concept and build an argument for an updated view of steles and their evolution. Studies of stelar organization have generated a widely ranging array of definitions that determine the way we classify steles and construct scenarios about the evolution of stelar architecture. Because at the organismal level biological evolution proceeds by changes in development, concepts of structure need to be grounded in development to be relevant in an evolutionary perspective. For the stele, most traditional definitions that incorporate development have viewed it as the totality of tissues that either originate from procambium - currently the prevailing view - or are bordered by a boundary layer (e.g. endodermis). Consensus between these two perspectives can be reached by recasting the stele as a structural entity of dual nature. Following a brief review of the history of the stele concept, basic terminology related to stelar organization, and traditional classifications of the steles, I revisit boundary layers from the perspective of histogenesis as a dynamic mosaic of developmental domains. I review anatomical and molecular data to explore and reaffirm the importance of boundary layers for stelar organization. Drawing on information from comparative anatomy, developmental regulation, and the fossil record, I propose a stele concept that integrates both the boundary layer and the procambial perspectives, consistent with a dual nature of the stele. This dual stele model posits that stelar architecture is determined at the apical meristem by two major cell fate specification events: a first one that specifies a provascular domain and its boundaries, and a second event that specifies a procambial domain (which will mature into conducting tissues) from cell subpopulations of the provascular domain. If the position and extent of the developmental domains defined by the two events are determined by different concentrations of the same morphogen (most likely auxin), then the distribution of this organizer factor in the shoot apical meristem, as modulated by changes in axis size and the effect of lateral organs, can explain the different stelar configurations documented among tracheophytes. This model provides working hypotheses that incorporate assumptions and generate implications that can be tested empirically. The model also offers criteria for an updated classification of steles in line with current understanding of plant development. In this classification, steles fall into two major categories determined by the configuration of boundary layers: boundary protosteles and boundary siphonosteles, each with subtypes defined by the architecture of the vascular tissues. Validation of the dual stele model and, more generally, in-depth understanding of the regulation of stelar architecture, will necessitate targeted efforts in two areas: (i) the regulation of procambium, vascular tissue, and boundary layer specification in all extant vascular plants, considering that most of the diversity in stelar architecture is hosted by seed-free plants, which are the least explored in terms of developmental regulation; (ii) the configuration of vascular tissues and, especially, boundary layers, in as many extinct lineages as possible.
PMID: 33655608
Plant Cell , IF:9.618 , 2021 Mar doi: 10.1093/plcell/koab076
Mapping and engineering of auxin-induced plasma membrane dissociation in BRX family proteins.
Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland.; Plant Systems Biology, Technical University of Munich, 85354 Freising, Germany.
Angiosperms have evolved the phloem for the long-distance transport of metabolites. The complex process of phloem development involves genes that only occur in vascular plant lineages. For example, in Arabidopsis thaliana, the BREVIS RADIX (BRX) gene is required for continuous root protophloem differentiation, together with PROTEIN KINASE ASSOCIATED WITH BRX (PAX). BRX and its BRX-LIKE (BRXL) homologs are composed of four highly conserved domains including the signature tandem BRX domains that are separated by variable spacers. Nevertheless, BRX family proteins have functionally diverged. For instance, BRXL2 can only partially replace BRX in the root protophloem. This divergence is reflected in physiologically relevant differences in protein behavior, such as auxin-induced plasma membrane dissociation of BRX, which is not observed for BRXL2. Here we dissected the differential functions of BRX family proteins using a set of amino acid substitutions and domain swaps. Our data suggest that the plasma membrane-associated tandem BRX domains are both necessary and sufficient to convey the biological outputs of BRX function and therefore constitute an important regulatory entity. Moreover, PAX target phosphosites in the linker between the two BRX domains mediate the auxin-induced plasma membrane dissociation. Engineering these sites into BRXL2 renders this modified protein auxin-responsive and thereby increases its biological activity in the root protophloem context.
PMID: 33751121
Plant Cell , IF:9.618 , 2021 Mar doi: 10.1093/plcell/koab084
The Arabidopsis MATERNAL EFFECT EMBRYO ARREST45 Protein Modulates Maternal Auxin Biosynthesis and Controls Seed Size by Inducing AINTEGUMENTA.
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China.; Novogene Bioinformatics Institute, Beijing, 100020, China.
Seed size is a major factor determining crop yields that is controlled through the coordinated development of maternal and zygotic tissues. Here, we identified Arabidopsis MATERNAL EFFECT EMBRYO ARREST45 (MEE45) as a B3 transcription factor that controls cell proliferation and maternally regulates seed size through its transcriptional activation of AINTEGUMENTA (ANT) and its downstream control of auxin biosynthesis in the ovule integument. After characterizing reduced seed and organ size phenotypes in mee45 mutants and finding that overexpression of MEE45 causes oversized seeds, we discovered that the MEE45 protein can bind to the promoter region of the ANT locus and positively regulate its transcription. ANT in-turn activates expression of auxin biosynthetic genes (e.g., YUCCA4) in the ovule integument. Our results thus illustrate mechanisms underlying maternal tissue-mediated regulation of seed size and suggest that MEE45 and its downstream components can be harnessed to develop higher yielding crop varieties.
PMID: 33730150
Plant Cell , IF:9.618 , 2021 Mar doi: 10.1093/plcell/koab080
The microtubule-associated protein WDL4 modulates auxin distribution to promote apical hook opening in Arabidopsis.
State Key Laboratory of Plant Physiology and Biochemistry; Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
The unique apical hook in dicotyledonous plants protects the shoot apical meristem and cotyledons when seedlings emerge through the soil. Its formation involves differential cell growth under the coordinated control of plant hormones, especially ethylene and auxin. Microtubules are an essential player in plant cell growth that are regulated by multiple microtubule-associated proteins (MAPs). However, the role and underlying mechanisms of MAP-microtubule modules in differential cell growth are poorly understood. In this study, we found that the previously uncharacterized Arabidopsis MAP WAVE-DAMPENED2-LIKE4 (WDL4) protein plays a positive role in apical hook opening. WDL4 exhibits a temporal expression pattern during hook development in dark-grown seedlings that is directly regulated by ethylene signaling. WDL4 mutants showed a delayed hook opening phenotype while overexpression of WDL4 resulted in enhanced hook opening. In particular, wdl4-1 mutants exhibited stronger auxin accumulation in the concave side of the apical hook. Furthermore, the regulation of the auxin maxima and trafficking of the auxin efflux carriers PIN-FORMED1 (PIN1) and PIN7 in the hook region is critical for WDL4-mediated hook opening. Together, our study demonstrates that WDL4 positively regulates apical hook opening by modulating auxin distribution, thus unraveling a mechanism for MAP-mediated differential plant cell growth.
PMID: 33730147
Plant Cell , IF:9.618 , 2021 Mar , V33 (1) : P44-65 doi: 10.1093/plcell/koaa012
Spatial transcriptional signatures define margin morphogenesis along the proximal-distal and medio-lateral axes in tomato (Solanum lycopersicum) leaves.
Department of Molecular and Cellular Biology, University of California at Berkeley, Berkeley, CA 94709.; Berkeley Institute for Data Science, University of California at Berkeley, Berkeley, CA 94709.; Department of Plant Biology, University of California at Davis, Davis, CA 95616.; RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, 15 230-0045 Japan.
Leaf morphogenesis involves cell division, expansion, and differentiation in the developing leaf, which take place at different rates and at different positions along the medio-lateral and proximal-distal leaf axes. The gene expression changes that control cell fate along these axes remain elusive due to difficulties in precisely isolating tissues. Here, we combined rigorous early leaf characterization, laser capture microdissection, and transcriptomic sequencing to ask how gene expression patterns regulate early leaf morphogenesis in wild-type tomato (Solanum lycopersicum) and the leaf morphogenesis mutant trifoliate. We observed transcriptional regulation of cell differentiation along the proximal-distal axis and identified molecular signatures delineating the classically defined marginal meristem/blastozone region during early leaf development. We describe the role of endoreduplication during leaf development, when and where leaf cells first achieve photosynthetic competency, and the regulation of auxin transport and signaling along the leaf axes. Knockout mutants of BLADE-ON-PETIOLE2 exhibited ectopic shoot apical meristem formation on leaves, highlighting the role of this gene in regulating margin tissue identity. We mapped gene expression signatures in specific leaf domains and evaluated the role of each domain in conferring indeterminacy and permitting blade outgrowth. Finally, we generated a global gene expression atlas of the early developing compound leaf.
PMID: 33710280
Curr Biol , IF:9.601 , 2021 Mar , V31 (6) : PR306-R309 doi: 10.1016/j.cub.2021.01.031
Plant biology: Positive feedback between auxin and cell wall mechanics during apical hook formation.
Integrated Molecular Plant Physiology Research, Department of Biology, University of Antwerp, Antwerp, Belgium; Plant Biochemistry and Biotechnology Lab, Department of Agriculture, Hellenic Mediterranean University, Stavromenos PC 71410, Heraklion, Crete, Greece. Electronic address: kris.vissenberg@uantwerpen.be.
Apical hook formation protects fragile tissues of the hypocotyl in soil during seedling emergence. A new study reveals a positive feedback loop between asymmetric distribution of the hormone auxin and the cell wall pectin conformations underpinning cell elongation and tissue bending.
PMID: 33756147
Curr Biol , IF:9.601 , 2021 Mar doi: 10.1016/j.cub.2021.02.028
AGC kinases and MAB4/MEL proteins maintain PIN polarity by limiting lateral diffusion in plant cells.
Institute of Science and Technology Austria (IST Austria), 3400 Klosterneuburg, Austria; Department of Experimental Plant Biology, Faculty of Science, Charles University, 12844 Prague, Czechia; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, 9052 Ghent, Belgium.; Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, 2333 BE Leiden, the Netherlands; Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3584 CH Utrecht, the Netherlands.; Institute of Science and Technology Austria (IST Austria), 3400 Klosterneuburg, Austria.; Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.; Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, 2333 BE Leiden, the Netherlands.; Institute of Science and Technology Austria (IST Austria), 3400 Klosterneuburg, Austria; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, (BOKU), 1190 Vienna, Austria.; Institute of Science and Technology Austria (IST Austria), 3400 Klosterneuburg, Austria; Department of Experimental Plant Biology, Faculty of Science, Charles University, 12844 Prague, Czechia.; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, 9052 Ghent, Belgium.; Plant Developmental Genetics, Institute of Biology Leiden, Leiden University, 2333 BE Leiden, the Netherlands. Electronic address: r.offringa@biology.leidenuniv.nl.; Institute of Science and Technology Austria (IST Austria), 3400 Klosterneuburg, Austria. Electronic address: jiri.friml@ist.ac.at.
Polar subcellular localization of the PIN exporters of the phytohormone auxin is a key determinant of directional, intercellular auxin transport and thus a central topic of both plant cell and developmental biology. Arabidopsis mutants lacking PID, a kinase that phosphorylates PINs, or the MAB4/MEL proteins of unknown molecular function display PIN polarity defects and phenocopy pin mutants, but mechanistic insights into how these factors convey PIN polarity are missing. Here, by combining protein biochemistry with quantitative live-cell imaging, we demonstrate that PINs, MAB4/MELs, and AGC kinases interact in the same complex at the plasma membrane. MAB4/MELs are recruited to the plasma membrane by the PINs and in concert with the AGC kinases maintain PIN polarity through limiting lateral diffusion-based escape of PINs from the polar domain. The PIN-MAB4/MEL-PID protein complex has self-reinforcing properties thanks to positive feedback between AGC kinase-mediated PIN phosphorylation and MAB4/MEL recruitment. We thus uncover the molecular mechanism by which AGC kinases and MAB4/MEL proteins regulate PIN localization and plant development.
PMID: 33705718
Curr Biol , IF:9.601 , 2021 Mar , V31 (6) : P1154-1164.e3 doi: 10.1016/j.cub.2020.12.016
Mechanochemical feedback mediates tissue bending required for seedling emergence.
Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90187 Umea, Sweden. Electronic address: kristoffer.jonsson@slu.se.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90187 Umea, Sweden.; IRBV, Department of Biological Sciences, University of Montreal, 4101 Sherbrooke Est, Montreal H1X 2B2, QC, Canada.; Laboratoire Reproduction et Developpement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon, France.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90187 Umea, Sweden. Electronic address: rishi.bhalerao@slu.se.
Tissue bending is vital to plant development, as exemplified by apical hook formation during seedling emergence by bending of the hypocotyl. How tissue bending is coordinated during development remains poorly understood, especially in plants where cells are attached via rigid cell walls. Asymmetric distribution of the plant hormone auxin underlies differential cell elongation during apical hook formation. Yet the underlying mechanism remains unclear. Here, we demonstrate spatial correlation between asymmetric auxin distribution, methylesterified homogalacturonan (HG) pectin, and mechanical properties of the epidermal layer of the hypocotyl in Arabidopsis. Genetic and cell biological approaches show that this mechanochemical asymmetry is essential for differential cell elongation. We show that asymmetric auxin distribution underlies differential HG methylesterification, and conversely changes in HG methylesterification impact the auxin response domain. Our results suggest that a positive feedback loop between auxin distribution and HG methylesterification underpins asymmetric cell wall mechanochemical properties to promote tissue bending and seedling emergence.
PMID: 33417884
Proc Natl Acad Sci U S A , IF:9.412 , 2021 Mar , V118 (13) doi: 10.1073/pnas.2016304118
Phyllotactic patterning of gerbera flower heads.
Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, 00014 Helsinki, Finland.; Department of Computer Science, University of Calgary, Calgary, AB T2N 1N4, Canada.; Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, 00014 Helsinki, Finland; pwp@ucalgary.ca paula.elomaa@helsinki.fi.; Department of Computer Science, University of Calgary, Calgary, AB T2N 1N4, Canada pwp@ucalgary.ca paula.elomaa@helsinki.fi.
Phyllotaxis, the distribution of organs such as leaves and flowers on their support, is a key attribute of plant architecture. The geometric regularity of phyllotaxis has attracted multidisciplinary interest for centuries, resulting in an understanding of the patterns in the model plants Arabidopsis and tomato down to the molecular level. Nevertheless, the iconic example of phyllotaxis, the arrangement of individual florets into spirals in the heads of the daisy family of plants (Asteraceae), has not been fully explained. We integrate experimental data and computational models to explain phyllotaxis in Gerbera hybrida We show that phyllotactic patterning in gerbera is governed by changes in the size of the morphogenetically active zone coordinated with the growth of the head. The dynamics of these changes divides the patterning process into three phases: the development of an approximately circular pattern with a Fibonacci number of primordia near the head rim, its gradual transition to a zigzag pattern, and the development of a spiral pattern that fills the head on the template of this zigzag pattern. Fibonacci spiral numbers arise due to the intercalary insertion and lateral displacement of incipient primordia in the first phase. Our results demonstrate the essential role of the growth and active zone dynamics in the patterning of flower heads.
PMID: 33771923
J Hazard Mater , IF:9.038 , 2021 Mar , V405 : P124250 doi: 10.1016/j.jhazmat.2020.124250
Auxin metabolic network regulates the plant response to metalloids stress.
Department of Biotechnology, Indian Institute of Technology, Roorkee 247667, Uttarakhand, India.; National Center for Soybean Improvement, Key L aboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.; Plant Physiology Laboratory, Department of Botany, C.M.P. Degree College, University of Allahabad, Prayagraj 211002, India.; Department of Biochemistry, Cell and Molecular Biology, Estacion Experimental del Zaidin, Consejo Superior de Investigaciones Cientificas (CSIC), C/Profesor Albareda, 1, 18008 Granada, Spain.; Department of Biotechnology, Indian Institute of Technology, Roorkee 247667, Uttarakhand, India. Electronic address: shri.yadav@bt.iitr.ac.in.
Metalloids are among the major pollutants posing a risk to the environment and global food security. Plant roots uptake these toxic metalloids from the soil along with other essential minerals. Plants respond to metalloid stress by regulating the distribution and levels of various endogenous phytohormones. Recent research showed that auxin is instrumental in mediating resilience to metalloid-induced stress in plants. Exogenous supplementation of the auxin or plant growth-promoting micro-organisms (PGPMs) alleviates metalloid uptake, localization, and accumulation in the plant tissues, thereby improving plant growth under metalloid stress. Moreover, auxin triggers various biological responses such as the production of enzymatic and non-enzymatic antioxidants to combat nitro-oxidative stress induced by the metalloids. However, an in-depth understanding of the auxin stimulated molecular and physiological responses to the metalloid toxicity needs to be investigated in future studies. The current review attempts to provide an update on the recent advances and the current state-of-the-art associated with auxin and metalloid interaction, which could be used as a start point to develop biotechnological tools and create an eco-friendly environment.
PMID: 33109410
New Phytol , IF:8.512 , 2021 Mar doi: 10.1111/nph.17354
Small kernel 501 (smk501) encodes the RUBylation activating enzyme E1 subunit ECR1 (E1 C-TERMINAL RELATED 1) and is essential for multiple aspects of cellular events during kernel development in maize.
Beijing Innovation Center for Crop Seed Technology, Ministry of Agriculture and Rural Affairs, Key Laboratory of Crop Heterosis Utilization, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China.; Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
RUBylation plays essential roles in plant growth and development through regulating Cullin-RING ubiquitin E3 ligase (CRL) activities and the CRL-mediated protein degradations. However, the function of RUBylation in regulating kernel development remains unclear. Through genetic and molecular analyses of a small kernel 501 (smk501) mutant in maize (Zea mays L.), we cloned the smk501 gene, revealed its molecular function, and defined its roles in RUBylation pathway and seed development. Smk501 encodes a RUBylation activating enzyme E1 subunit ZmECR1 (E1 C-TERMINAL RELATED 1) protein. Destruction in RUBylation by smk501 mutation resulted in less embryo and endosperm cell number and smaller kernel size. The transcriptome and proteome profiling, hormone evaluation and cell proliferation observation revealed that disturbing ZmECR1 expression mainly affects pathways on hormone signal transduction, cell cycle progression and starch accumulation during kernel development. In addition, mutant in zmaxr1 (Auxin resistant 1), another RUB E1 subunit, also showed similar defects in kernel development. Double mutation of zmecr1 and zmaxr1 lead to empty pericarp kernel phenotype. RUBylation is a novel regulatory pathway affecting maize kernel development, majorly through its functions in modifying multiple cellular progresses.
PMID: 33749863
New Phytol , IF:8.512 , 2021 Mar doi: 10.1111/nph.17349
Seedling developmental defects upon blocking CINNAMATE-4-HYDROXYLASE are caused by perturbations in auxin transport.
Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, B-9052, Ghent, Belgium.; VIB Center for Plant Systems Biology, Technologiepark 71, B-9052, Ghent, Belgium.; Institute of Science and Technology (IST) Austria, 3400, Klosterneuburg, Austria.; VIB Metabolomics Core, 9052, Ghent, Belgium.; School of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom.
* The phenylpropanoid pathway serves a central role in plant metabolism, providing numerous compounds involved in diverse physiological processes. Most carbon entering the pathway is incorporated into lignin. Although several phenylpropanoid pathway mutants show seedling growth arrest, the role for lignin in seedling growth and development is unexplored. * We use complementary pharmacological and genetic approaches to block CINNAMATE-4-HYDROXYLASE (C4H) functionality in Arabidopsis seedlings and a set of molecular and biochemical techniques to investigate the underlying phenotypes. * Blocking C4H resulted in reduced lateral rooting and increased adventitious rooting apically in the hypocotyl. These phenotypes coincided with an inhibition in auxin transport. The upstream accumulation in cis-cinnamic acid was found to likely cause polar auxin transport inhibition. Conversely, a downstream depletion in lignin perturbed phloem-mediated auxin transport. Restoring lignin deposition effectively reestablished phloem transport and, accordingly, auxin homeostasis. * Our results show that the accumulation of bioactive intermediates and depletion in lignin jointly cause the aberrant phenotypes upon blocking C4H, and demonstrate that proper deposition of lignin is essential for the establishment of auxin distribution in seedlings. Our data position the phenylpropanoid pathway and lignin in a new physiological framework, consolidating their importance in plant growth and development.
PMID: 33728703
Cold Spring Harb Perspect Biol , IF:7.64 , 2021 Mar doi: 10.1101/cshperspect.a040022
Auxin Plays Multiple Roles during Plant-Pathogen Interactions.
Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, USA.
The plant hormone auxin governs many aspects of normal plant growth and development. Auxin also plays an important role in plant-microbe interactions, including interactions between plant hosts and pathogenic microorganisms that cause disease. It is now well established that indole-3-acetic acid (IAA), the most well-studied form of auxin, promotes disease in many plant-pathogen interactions. Recent studies have shown that IAA can act both as a plant hormone that modulates host signaling and physiology to increase host susceptibility and as a microbial signal that directly impacts the pathogen to promote virulence, but large gaps in our understanding remain. In this article, we review recent studies on the roles that auxin plays during plant-pathogen interactions and discuss the virulence mechanisms that many plant pathogens have evolved to manipulate host auxin signaling and promote pathogenesis.
PMID: 33782029
Plant Physiol , IF:6.902 , 2021 Mar doi: 10.1093/plphys/kiab133
The flat of the blade: auxin provides the positional cue for unifacial leaf blade flattening.
The Sainsbury Laboratory, University of Cambridge, CB2 1LR Cambridge, UK.
PMID: 33769544
Plant Physiol , IF:6.902 , 2021 Mar doi: 10.1093/plphys/kiab132
Auxin does not inhibit endocytosis of PIN1 and PIN2 auxin efflux carrierss.
Plant Systems Biology, School of Life Sciences, Technical University of Munich, Emil-Ramann-Strasse 8, 85354 Freising, Germany.; School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 6997801, Israel.; Department of Experimental Plant Biology, Faculty of Science, Charles University, 12800 Prague, Czech Republic.; Laboratory of Cell Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 16502 Prague, Czech Republic.
PMID: 33769526
Plant Physiol , IF:6.902 , 2021 Mar doi: 10.1093/plphys/kiab118
What remains of the evidence for auxin feedback on PIN polarity patterns?
Department of Theoretical Biology, Faculty of Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
PMID: 33760101
Plant Physiol , IF:6.902 , 2021 Mar doi: 10.1093/plphys/kiab138
Mitochondrial Heat Shock Cognate Protein 70 Contributes to Auxinmediated Embryo Development.
Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, and Tianjin Key Laboratory of Protein Sciences, 300071 Tianjin, China.; Department of Plant Sciences, MIGAL-Galilee Research Institute, Kiryat-Shmona 11016, Israel.; State Key Laboratory of Medicinal Chemical Biology, Nankai University, 94 Weijin Road, Tianjin 300071, China.; Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, and Tianjin Key Laboratory of Protein Sciences, 300071 Tianjin, China.
In Arabidopsis thaliana, mitochondrial-localized heat shock cognate protein 70-1 (mtHSC70-1) plays an important role in vegetative growth. However, whether mtHSC70-1 affects reproductive growth remains unknown. Here, we found that the mtHSC70-1 gene was expressed in the provascular cells of the embryo proper from the early heart stage onward during embryogenesis. Phenotypic analyses of mthsc70-1 mutants revealed that mtHSC70 deficiency leads to defective embryo development and that this effect is mediated by auxin. In addition to a dwarf phenotype, the mthsc70-1 mutant displayed defects in flower morphology, anther development, and embryogenesis. At early developmental stages, the mthsc70-1 embryos exhibited abnormal cell divisions in both embryo proper and suspensor cells. From heart stage onward, they displayed an abnormal shape such as with no or very small cotyledon protrusions, had aberrant number of cotyledons, or were twisted. These embryo defects were associated with reduced or ectopic expression of auxin responsive reporter DR5rev:GFP. Consistently, the expression of auxin biosynthesis and polar auxin transport genes were markedly altered in mthsc70-1. On the other hand, mitochondrial retrograde regulation (MRR) was enhanced in mthsc70-1. Treatment of wild-type plants with an inhibitor that activates mitochondrial retrograde signaling reduced the expression level of auxin biosynthesis and polar auxin transport genes and induced phenotypes similar to those of mthsc70-1. Taken together, our data reveal that loss of function of mtHSC70-1 induces MRR, which inhibits auxin biosynthesis and polar auxin transport, leading to abnormal auxin gradients and defective embryo development.
PMID: 33744930
Plant Physiol , IF:6.902 , 2021 Mar doi: 10.1093/plphys/kiab132
Auxin does not inhibit endocytosis of PIN1 and PIN2 auxin efflux carriers.
Plant Systems Biology, School of Life Sciences, Technical University of Munich, Emil-Ramann-Strasse 8, 85354 Freising, Germany.; School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 6997801, Israel.; Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic.; Laboratory of Cell Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czech Republic.
PMID: 33742679
Plant Physiol , IF:6.902 , 2021 Mar doi: 10.1093/plphys/kiab134
Systematic analysis of specific and nonspecific auxin effects on endocytosis and trafficking.
Institute of Science and Technology (IST), Klosterneuburg 3400, Austria.; Ghent University, Department of Plant Biotechnology and Bioinformatics, 9052 Gent, Belgium.; Departamento de Bioquimica y Biologia Molecular, Facultad de Farmacia, Universitat de Valencia, 46100 Burjassot, Spain.
The phytohormone auxin and its directional transport through tissues are intensively studied. However, a mechanistic understanding of auxin-mediated feedback on endocytosis and polar distribution of PIN auxin transporters remains limited due to contradictory observations and interpretations. Here, we used state-of-the-art methods to reexamine the auxin effects on PIN endocytic trafficking. We used high auxin concentrations or longer treatments versus lower concentrations and shorter treatments of natural (IAA) and synthetic (NAA) auxins to distinguish between specific and nonspecific effects. Longer treatments of both auxins interfere with Brefeldin A-mediated intracellular PIN2 accumulation and also with general aggregation of endomembrane compartments. NAA treatment decreased the internalization of the endocytic tracer dye, FM4-64; however, NAA treatment also affected the number, distribution, and compartment identity of the early endosome/trans-Golgi network (EE/TGN), rendering the FM4-64 endocytic assays at high NAA concentrations unreliable. To circumvent these nonspecific effects of NAA and IAA affecting the endomembrane system, we opted for alternative approaches visualizing the endocytic events directly at the plasma membrane (PM). Using Total Internal Reflection Fluorescence (TIRF) microscopy, we saw no significant effects of IAA or NAA treatments on the incidence and dynamics of clathrin foci, implying that these treatments do not affect the overall endocytosis rate. However, both NAA and IAA at low concentrations rapidly and specifically promoted endocytosis of photo-converted PIN2 from the PM. These analyses identify a specific effect of NAA and IAA on PIN2 endocytosis, thus contributing to its polarity maintenance and furthermore illustrate that high auxin levels have nonspecific effects on trafficking and endomembrane compartments.
PMID: 33734402
Plant Physiol , IF:6.902 , 2021 Mar doi: 10.1093/plphys/kiab130
AUXIN RESPONSE FACTOR 18-HISTONE DEACETYLASE 6 module regulates floral organ identity in rose (Rosa hybrida).
State Key Laboratory of Agrobiotechnology, Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture, College of Horticulture, China Agricultural University, Beijing 100193, China.; School of Applied Chemistry and Biotechnology, Shenzhen Polytechnic, Shenzhen, Guangdong 518055, China.; LVMH Recherche, 185 avenue de Verdun F-45800 St Jean de Braye, France.; Shanghai Academy of Agricultural Sciences, Shanghai 201403, China.; State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China.; Crop Pathology and Genetic Research Unit, United States Department of Agriculture, Agricultural Research Service, Davis, CA, USA.; Department of Plant Sciences, University of California, Davis, CA, USA.; Plant Biology Section, School of Integrative Plant Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, USA.
The phytohormone auxin plays a pivotal role in floral meristem initiation and gynoecium development, but whether and how auxin controls floral organ identity remain largely unknown. Here, we found that auxin levels influence organ specification, and changes in auxin levels influence homeotic transformation between petals and stamens in rose (Rosa hybrida). The PIN-FORMED-LIKES (PILS) gene RhPILS1 governs auxin levels in floral buds during floral organogenesis. RhAUXIN RESPONSE FACTOR 18 (RhARF18), whose expression decreases with increasing auxin content, encodes a transcriptional repressor of the C-class gene RhAGAMOUS (RhAG) and controls stamen-petal organ specification in an auxin-dependent manner. Moreover, RhARF18 physically interacts with the histone deacetylase (HDA) RhHDA6. Silencing of RhHDA6 increases H3K9/K14 acetylation levels at the site adjacent to the RhARF18-binding site in the RhAG promoter and reduces petal number, indicating that RhARF18 might recruit RhHDA6 to the RhAG promoter to reinforce the repression of RhAG transcription. We propose a model for how auxin homeostasis controls floral organ identity via regulating transcription of RhAG.
PMID: 33729501
Plant Physiol , IF:6.902 , 2021 Mar , V185 (2) : P405-423 doi: 10.1093/plphys/kiaa051
A temperature-sensitive FERONIA mutant allele that alters root hair growth.
Division of Applied Life Sciences (BK21plus), Graduate School of Gyeongsang National University, Jinju 660-701, Republic of Korea.; Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA.; Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
In plants, root hairs undergo a highly polarized form of cell expansion called tip-growth, in which cell wall deposition is restricted to the root hair apex. In order to identify essential cellular components that might have been missed in earlier genetic screens, we identified conditional temperature-sensitive (ts) root hair mutants by ethyl methanesulfonate mutagenesis in Arabidopsis thaliana. Here, we describe one of these mutants, feronia-temperature sensitive (fer-ts). Mutant fer-ts seedlings were unaffected at normal temperatures (20 degrees C), but failed to form root hairs at elevated temperatures (30 degrees C). Map based-cloning and whole-genome sequencing revealed that fer-ts resulted from a G41S substitution in the extracellular domain of FERONIA (FER). A functional fluorescent fusion of FER containing the fer-ts mutation localized to plasma membranes, but was subject to enhanced protein turnover at elevated temperatures. While tip-growth was rapidly inhibited by addition of rapid alkalinization factor 1 (RALF1) peptides in both wild-type and fer-ts mutants at normal temperatures, root elongation of fer-ts seedlings was resistant to added RALF1 peptide at elevated temperatures. Additionally, at elevated temperatures fer-ts seedlings displayed altered reactive oxygen species (ROS) accumulation upon auxin treatment and phenocopied constitutive fer mutant responses to a variety of plant hormone treatments. Molecular modeling and sequence comparison with other Catharanthus roseus receptor-like kinase 1L (CrRLK1L) receptor family members revealed that the mutated glycine in fer-ts is highly conserved, but is not located within the recently characterized RALF23 and LORELI-LIKE-GLYCOPROTEIN 2 binding domains, perhaps suggesting that fer-ts phenotypes may not be directly due to loss of binding to RALF1 peptides.
PMID: 33721904
Plant Physiol , IF:6.902 , 2021 Mar , V185 (2) : P503-518 doi: 10.1093/plphys/kiaa032
Characterization of CYCLOPHILLIN38 shows that a photosynthesis-derived systemic signal controls lateral root emergence.
Biology Department, Stanford University, Stanford, CA 94305, USA.; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA.; Instituto de Bioquimica Vegetal y Fotosintesis, Universidad de Sevilla and Consejo Superior de Investigaciones Cientificas, Avda Americo Vespucio 49, 41092 Sevilla, Spain.
Photosynthesis in leaves generates fixed-carbon resources and essential metabolites that support sink tissues, such as roots. Two of these metabolites, sucrose and auxin, promote growth in root systems, but the explicit connection between photosynthetic activity and control of root architecture has not been explored. Through a mutant screen to identify pathways regulating root system architecture, we identified a mutation in the Arabidopsis thaliana CYCLOPHILIN 38 (CYP38) gene, which causes accumulation of pre-emergent stage lateral roots. CYP38 was previously reported to stabilize photosystem II (PSII) in chloroplasts. CYP38 expression is enriched in shoots, and grafting experiments show that the gene acts non-cell-autonomously to promote lateral root emergence. Growth of wild-type plants under low-light conditions phenocopies the cyp38 lateral root emergence defect, as does the inhibition of PSII-dependent electron transport or Nicotinamide adenine dinucleotide phosphate (NADPH) production. Importantly, these perturbations to photosynthetic activity rapidly suppress lateral root emergence, which is separate from their effects on shoot size. Supplementary exogenous sucrose largely rescued primary root (PR) growth in cyp38, but not lateral root growth. Auxin (indole-3-acetic acid (IAA)) biosynthesis from tryptophan is dependent on reductant generated during photosynthesis. Consistently, we found that wild-type seedlings grown under low light and cyp38 mutants have highly diminished levels of IAA in root tissues. IAA treatment rescued the cyp38 lateral root defect, revealing that photosynthesis promotes lateral root emergence partly through IAA biosynthesis. These data directly confirm the importance of CYP38-dependent photosynthetic activity in supporting root growth, and define the specific contributions of two metabolites in refining root architecture under light-limited conditions.
PMID: 33721893
Genomics , IF:6.205 , 2021 Mar , V113 (3) : P1247-1261 doi: 10.1016/j.ygeno.2021.03.007
A comprehensive transcriptome analysis of contrasting rice cultivars highlights the role of auxin and ABA responsive genes in heat stress response.
Interdisciplinary Centre for Plant Genomics, University of Delhi South Campus, New Delhi 110021, India.; Indian Council of Agricultural Research, Krishi Bhawan, New Delhi 110001, India.; Interdisciplinary Centre for Plant Genomics, University of Delhi South Campus, New Delhi 110021, India; Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India.; Interdisciplinary Centre for Plant Genomics, University of Delhi South Campus, New Delhi 110021, India; Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110021, India. Electronic address: khuranaj@genomeindia.org.
Sensing a change in ambient temperature is key to survival among all living organisms. Temperature fluctuations due to climate change are a matter of grave concern since it adversely affects growth and eventually the yield of crop plants, including two of the major cereals, i.e., rice and wheat. Thus, to understand the response of rice seedlings to elevated temperatures, we performed microarray-based transcriptome analysis of two contrasting rice cultivars, Annapurna (heat tolerant) and IR64 (heat susceptible), by subjecting their seedlings to 37 degrees C and 42 degrees C, sequentially. The transcriptome analyses revealed a set of uniquely regulated genes and related pathways in red rice cultivar Annapurna, particularly associated with auxin and ABA as a part of heat stress response in rice. The changes in expression of few auxin and ABA associated genes, such as OsIAA13, OsIAA20, ILL8, OsbZIP12, OsPP2C51, OsDi19-1 and OsHOX24, among others, were validated under high-temperature conditions using RT-qPCR. In particular, the expression of auxin-inducible SAUR genes was enhanced considerably at both elevated temperatures. Further, using genes that expressed inversely under heat vs. cold temperature conditions, we built a regulatory network between transcription factors (TF) such as HSFs, NAC, WRKYs, bHLHs or bZIPs and their target gene pairs and determined regulatory coordination in their expression under varying temperature conditions. Our work thus provides useful insights into temperature-responsive genes, particularly under elevated temperature conditions, and could serve as a resource of candidate genes associated with thermotolerance or downstream components of temperature sensors in rice.
PMID: 33705886
Plant J , IF:6.141 , 2021 Mar doi: 10.1111/tpj.15250
The chemical compound 'Heatin' stimulates hypocotyl elongation and interferes with the Arabidopsis NIT1-subfamily of nitrilases.
Molecular Plant Physiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.; Department of Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Universitatsstrasse 150, 44801, Bochum, Germany.; Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, University Utrecht, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands.; Plant Chemetics Laboratory, Department of Plant Sciences, University of Oxford, South Parks Road, OX1 3RB, Oxford, United Kingdom.; Chemische Biologie, Zentrum fur Medizinische Biotechnologie, Fakultat fur Biologie, Universitat Duisburg-Essen, Universitatsstr. 2, 45117, Essen, Germany.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umea, Sweden.; Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences & Faculty of Science, Palacky University, Slechtitelu 27, 78371, Olomouc, Czech Republic.; Bejo Zaden B.V, Trambaan 1, 1749 CZ, Warmenhuizen, The Netherlands.; Plant-Microbe Interactions, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.; Theoretical Biology and Bioinformatics, Institute of Biodynamics and Biocomplexity, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.; Keygene, Agro Business Park 90, 6708, Wageningen, The Netherlands.; Bioscience, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.; Biological Chemistry Group, Institute of Biology Leiden, Leiden University, Sylvius Laboratories, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
Temperature passively affects biological processes involved in plant growth. It is therefore challenging to study the dedicated temperature signalling pathways that orchestrate thermomorphogenesis, a suite of elongation growth-based adaptations that enhance leaf cooling capacity. We screened a chemical library for compounds that restored hypocotyl elongation in the pif4-2 deficient mutant background at warm temperature conditions in Arabidopsis thaliana to identify modulators of thermomorphogenesis. The small aromatic compound 'Heatin', containing 1-iminomethyl-2-naphthol as pharmacophore, was selected as enhancer of elongation growth. We show that ARABIDOPSIS ALDEHYDE OXIDASES redundantly contribute to Heatin-mediated hypocotyl elongation. Following a chemical proteomics approach, the members of the NITRILASE1-subfamily of auxin biosynthesis enzymes were identified among the molecular targets of Heatin. Our data reveal that nitrilases are involved in promotion of hypocotyl elongation in response to high temperature and Heatin-mediated hypocotyl elongation requires the NITRILASE1-subfamily members NIT1 and NIT2. Heatin inhibits NIT1-subfamily enzymatic activity in vitro and Heatin application accordingly results in accumulation of NIT1-subfamily substrate indole-3-acetonitrile (IAN) in vivo. However, also levels of the NIT1-subfamily product, bioactive auxin (Indole-3-acetic acid; IAA), were significantly increased. Possibly, Heatin's stimulation of hypocotyl elongation might be independent of its observed interaction with NITRILASE1-subfamily members. But nitrilases may contribute to the Heatin response by stimulating IAA biosynthesis in an indirect way. Heatin and its functional analogues present novel chemical entities for studying auxin biology.
PMID: 33768644
Plant J , IF:6.141 , 2021 Mar doi: 10.1111/tpj.15226
The transcriptomic landscapes of rice cultivars with diverse root system architectures grown in upland field conditions.
Institute of Agrobiological Sciences, National Agriculture & Food Research Organization, Tsukuba, Ibaraki, 305-8604, Japan.; Institute of Crop Sciences, National Agriculture & Food Research Organization, Tsukuba, Ibaraki, 305-8602, Japan.
Root system architecture affects plant drought resistance and other key agronomic traits such as lodging. However, although phenotypic and genomic variation has been extensively analyzed, few field studies have integrated phenotypic and transcriptomic information, especially for below-ground traits such as root system architecture. Here, we report the phenotypic and transcriptomic landscape of 61 rice (Oryza sativa) accessions with highly diverse below-ground traits grown in an upland field. We found that four principal components explained the phenotypic variation and that accessions could be classified into four subpopulations (indica, aus, japonica, and admixed) based on their tiller numbers and crown root diameters. Transcriptome analysis revealed that differentially expressed genes associated with specific subpopulations were enriched with stress response-related genes, suggesting that subpopulations have distinct stress response mechanisms. Root growth was negatively correlated with auxin-inducible genes, suggesting an association between auxin signaling and upland field conditions. A negative correlation between crown root diameter and stress response-related genes suggested that thicker crown root diameter is associated with resistance to mild drought stress. Finally, co-expression network analysis implemented with DNA affinity purification followed by sequencing (DAP-seq) analysis identified phytohormone signaling networks and key transcription factors negatively regulating crown root diameter. Our datasets provide a useful resource for understanding the genomic and transcriptomic basis of phenotypic variation under upland field conditions.
PMID: 33751672
J Exp Bot , IF:5.908 , 2021 Mar doi: 10.1093/jxb/erab106
Auxin signaling and vascular cambium formation enables storage metabolism in cassava tuberous roots.
Friedrich-Alexander-University Erlangen-Nuremberg, Department of Biology, Division of Biochemistry, Erlangen, Germany.; International Institute for Tropical Agriculture, Ibadan, Oyo State, Nigeria.; Institute for Sustainable Plant Protection, CNR, Bari, Italy.; Technical University Kaiserslautern, Department of Biology, Division of Plant Physiology, Kaiserslautern.; Institute for Biomedical Technologies, CNR, Bari, Italy.; KWS Saat SE, Grimsehlstrasse, Einbeck, Germany.
Cassava storage roots are among the most important root crops worldwide and represent one of the most consumed staple foods in Sub-Saharan Africa. The vegetatively propagated tropical shrub can form many starchy tuberous roots from its stem. These storage roots are formed through the activation of secondary root growth processes. However, the underlying genetic regulation of storage root development is largely unknown. Here we report on distinct structural and transcriptional changes occurring during the early phases of storage root development. A pronounced increase in auxin-related transcripts and the transcriptional activation of secondary growth factors, as well as a decrease in gibberellin-related transcripts was observed during the early stages of secondary root growth. This was accompanied by increased cell wall biosynthesis, increased most notably during the initial xylem expansion within the root vasculature. Starch storage metabolism was activated only after the formation of the vascular cambium. The formation of non-lignified xylem parenchyma cells and the activation of starch storage metabolism coincided with increased expression of the KNOX/BEL genes KNAT1, PENNYWISE and POUND-FOOLISH, indicating their importance for proper xylem parenchyma function.
PMID: 33712830
J Exp Bot , IF:5.908 , 2021 Mar doi: 10.1093/jxb/erab094
Potential interaction between autophagy and auxin during maize leaf senescence implicated by population genetics and high resolution gene expression profiling.
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, China.; University of Chinese Academy of Sciences, Beijing, China.; Institute of Agricultural Biotechnology, Jilin Academy of Agricultural Sciences, Changchun, Jilin, China.; Engineering Laboratory for Grass-based Livestock Husbandry, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Leaf senescence is important for crop yield. In this study, population genetics and transcriptomic profiling were combined to dissect its genetic basis in maize. For this, the progenies of an elite maize hybrid Jidan27 and its parental lines Si-287 (early senescence) and Si-144 (stay-green), as well as 173 maize inbred lines were used, and two novel loci and their candidate genes, Stg3 (ZmATG18b) and Stg7 (ZmGH3.8) were identified, which are predicted to be the members of autophagy and auxin pathways, respectively. Genomic variations in the promoter regions of these two genes were detected, and four allelic combinations existed in the examined maize inbred lines. The Stg3 Si-144/Stg7 Si-144 allelic combination with a lower ZmATG18b expression level and higher ZmGH3.8 expression level could distinctively delay leaf senescence, increase ear weight and significantly reduce ear weight loss under drought stress, while opposite effects were observed in the Stg3 Si-287/Stg7 Si-287 combination with a higher ZmATG18b expression level and lower ZmGH3.8 expression level. Thus, we identify a potential interaction between autophagy and auxin which could modulate the timing of maize leaf senescence.
PMID: 33684202
J Exp Bot , IF:5.908 , 2021 Mar , V72 (7) : P2356-2370 doi: 10.1093/jxb/erab034
Phytohormones and their crosstalk in regulating stomatal development and patterning.
School of Life Sciences, Southwest University, Chongqing 400715, China.; College of Life Sciences, South China Agricultural University, Guangzhou 510642, China.; College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot 010018, China.
Phytohormones play important roles in regulating various aspects of plant growth and development as well as in biotic and abiotic stress responses. Stomata are openings on the surface of land plants that control gas exchange with the environment. Accumulating evidence shows that various phytohormones, including abscisic acid, jasmonic acid, brassinosteroids, auxin, cytokinin, ethylene, and gibberellic acid, play many roles in the regulation of stomatal development and patterning, and that the cotyledons/leaves and hypocotyls/stems of Arabidopsis exhibit differential responsiveness to phytohormones. In this review, we first discuss the shared regulatory mechanisms controlling stomatal development and patterning in Arabidopsis cotyledons and hypocotyls and those that are distinct. We then summarize current knowledge of how distinct hormonal signaling circuits are integrated into the core stomatal development pathways and how different phytohormones crosstalk to tailor stomatal density and spacing patterns. Knowledge obtained from Arabidopsis may pave the way for future research to elucidate the effects of phytohormones in regulating stomatal development and patterning in cereal grasses for the purpose of increasing crop adaptive responses.
PMID: 33512461
J Exp Bot , IF:5.908 , 2021 Mar , V72 (7) : P2501-2513 doi: 10.1093/jxb/erab025
Coordination between MIDASIN 1-mediated ribosome biogenesis and auxin modulates plant development.
Biotechnology Research Center, Shandong Academy of Agricultural Sciences; Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan 250100, PR China.; College of Life Science, Shandong University, Qingdao 266237, PR China.; College of Life Sciences, Shandong Normal University, Jinan 250014, PR China.
Ribosomes are required for plant growth and development, and ribosome biogenesis-deficient mutants generally display auxin-related phenotypes. Although the relationship between ribosome dysfunction and auxin is known, many aspects of this subject remain to be understood. We previously reported that MIDASIN 1 (MDN1) is an essential pre-60S ribosome biogenesis factor (RBF) in Arabidopsis. In this study, we further characterized the aberrant auxin-related phenotypes of mdn1-1, a weak mutant allele of MDN1. Auxin response is disturbed in both shoots and roots of mdn1-1, as indicated by the DR5:GUS reporter. By combining transcriptome profiling analysis and reporter gene detection, we found that expression of genes involved in auxin biosynthesis, transport, and signaling is changed in mdn1-1. Furthermore, MDN1 deficiency affects the post-transcriptional regulation and protein distribution of PIN-FORMED 2 (PIN2, an auxin efflux facilitator) in mdn1-1 roots. These results indicate that MDN1 is required for maintaining the auxin system. More interestingly, MDN1 is an auxin-responsive gene, and its promoter can be targeted by multiple AUXIN RESPONSE FACTORs (ARFs), including ARF7 and ARF19, in vitro. Indeed, in arf7 arf19, the auxin sensitivity of MDN1 expression is significantly reduced. Together, our results reveal a coordination mechanism between auxin and MDN1-dependent ribosome biogenesis for regulating plant development.
PMID: 33476386
J Exp Bot , IF:5.908 , 2021 Mar , V72 (7) : P2288-2300 doi: 10.1093/jxb/erab009
The production of auxin by dying cells.
Fellow of Schumacher College, Dartington, Devon, UK.
In this review, I discuss the possibility that dying cells produce much of the auxin in vascular plants. The natural auxin, indole-3-acetic acid (IAA), is derived from tryptophan by a two-step pathway via indole pyruvic acid. The first enzymes in the pathway, tryptophan aminotransferases, have a low affinity for tryptophan and break it down only when tryptophan levels rise far above normal intracellular concentrations. Such increases occur when tryptophan is released from proteins by hydrolytic enzymes as cells autolyse and die. Many sites of auxin production are in and around dying cells: in differentiating tracheary elements; in root cap cells; in nutritive tissues that break down in developing flowers and seeds; in senescent leaves; and in wounds. Living cells also produce auxin, such as those transformed genetically by the crown gall pathogen. IAA may first have served as an exogenous indicator of the presence of nutrient-rich decomposing organic matter, stimulating the production of rhizoids in bryophytes. As cell death was internalized in bryophytes and in vascular plants, IAA may have taken on a new role as an endogenous hormone.
PMID: 33460445
J Exp Bot , IF:5.908 , 2021 Mar , V72 (7) : P2450-2462 doi: 10.1093/jxb/eraa590
Alternate bearing in fruit trees: fruit presence induces polar auxin transport in citrus and olive stem and represses IAA release from the bud.
Department of Fruit Tree Sciences, The Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel.; The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.; CEBAS-CSIC, Department of Plant Nutrition, Campus Universitario de Espinardo, Espinardo, Murcia, Spain.
In many fruit trees, heavy fruit load in one year reduces flowering in the following year, creating a biennial fluctuation in yield termed alternate bearing (AB). In subtropical trees, where flowering induction is mostly governed by the accumulation of chilling hours, fruit load is thought to generate a signal (AB signal) that blocks the perception of cold induction. Fruit removal during a heavy-fruit-load year is effective at inducing flowering only if performed one to a few months before the onset of the flowering induction period. We previously showed that following fruit removal, the content of the auxin indoleacetic acid (IAA) in citrus buds is reduced, suggesting that the hormone plays a role in the AB signal. Here, we demonstrate that fruit presence generates relatively strong polar auxin transport in citrus and olive stems. Upon fruit removal, polar auxin transport is reduced and allows auxin release from the bud. Furthermore, using immunolocalization, hormone, and gene expression analyses, we show that in citrus, IAA level in the bud and specifically in the apical meristem is reduced upon fruit removal. Overall, our data provide support for the notion that fruit presence generates an auxin signal in the bud, which may affect flowering induction.
PMID: 33345278
Development , IF:5.611 , 2021 Mar , V148 (6) doi: 10.1242/dev.195347
Model systems for regeneration: Arabidopsis.
School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, 695551, India.; School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, 695551, India kalika@iisertvm.ac.in.
Plants encompass unparalleled multi-scale regenerative potential. Despite lacking specialized cells that are recruited to injured sites, and despite their cells being encased in rigid cell walls, plants exhibit a variety of regenerative responses ranging from the regeneration of specific cell types, tissues and organs, to the rebuilding of an entire organism. Over the years, extensive studies on embryo, shoot and root development in the model plant species Arabidopsis thaliana have provided insights into the mechanisms underlying plant regeneration. These studies highlight how Arabidopsis, with its wide array of refined molecular, genetic and cell biological tools, provides a perfect model to interrogate the cellular and molecular mechanisms of reprogramming during regeneration.
PMID: 33762427
Development , IF:5.611 , 2021 Mar , V148 (5) doi: 10.1242/dev.187120
Expansion and innovation in auxin signaling: where do we grow from here?
University of Washington, Department of Biology, Seattle, WA 98105-1800, USA rramosb@uw.edu jn7@uw.edu.
The phytohormone auxin plays a role in almost all growth and developmental responses. The primary mechanism of auxin action involves the regulation of transcription via a core signaling pathway comprising proteins belonging to three classes: receptors, co-receptor/co-repressors and transcription factors. Recent studies have revealed that auxin signaling can be traced back at least as far as the transition to land. Moreover, studies in flowering plants have highlighted how expansion of the gene families encoding auxin components is tied to functional diversification. As we review here, these studies paint a picture of auxin signaling evolution as a driver of innovation.
PMID: 33712444
Front Plant Sci , IF:4.402 , 2021 , V12 : P625493 doi: 10.3389/fpls.2021.625493
The Arabidopsis SMALL AUXIN UP RNA32 Protein Regulates ABA-Mediated Responses to Drought Stress.
Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.; College of Agronomy, Northwest A&F University, Yangling, China.; Department of Agriculture, University of Swabi, Swabi, Pakistan.; Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Zhejiang University, Hangzhou, China.
SMALL AUXIN UP-REGULATED RNAs (SAURs) are recognized as auxin-responsive genes involved in the regulation of abiotic stress adaptive growth. Among the growth-limiting factors, water-deficit condition significantly affects plant growth and development. The putative function of SAUR family member AtSAUR32 has the potential to diminish the negative impact of drought stress, but the exact function and mode of action remain unclear in Arabidopsis. In the current study, AtSAUR32 gene was cloned and functionally analyzed. AtSAUR32 localized to the plasma membrane and nucleus was dominantly expressed in roots and highly induced by abscisic acid and drought treatment at certain time points. The stomatal closure and seed germination of saur32 were less sensitive to ABA relative to AtSAUR32-overexpressed line (OE32-5) and wild type (WT). Moreover, the saur32 mutant under drought stress showed increased ion leakage while quantum yield of photosystem II (PhiPSII) and endogenous ABA accumulation were reduced, along with the expression pattern of ABA/stress-responsive genes compared with WT and the OE32-5 transgenic line. Additionally, yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays showed that AtSAUR32 interacted with clade-A PP2C proteins (AtHAI1 and AtAIP1) to regulate ABA sensitivity in Arabidopsis. Taken together, these results indicate that AtSAUR32 plays an important role in drought stress adaptation via mediating ABA signal transduction.
PMID: 33777065
Front Plant Sci , IF:4.402 , 2021 , V12 : P636098 doi: 10.3389/fpls.2021.636098
The Sequential Action of MIDA9/PP2C.D1, PP2C.D2, and PP2C.D5 Is Necessary to Form and Maintain the Hook After Germination in the Dark.
Plant Development and Signal Transduction Program, Center for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona, Spain.; Department of Botany, Graduate School of Science, Kyoto University, Kyoto, Japan.; Laboratory of Biochemistry, Institut Quimic de Sarria, Universitat Ramon Llull, Barcelona, Spain.; Consejo Superior de Investigaciones Cientificas (CSIC), Barcelona, Spain.
During seedling etiolation after germination in the dark, seedlings have closed cotyledons and form an apical hook to protect the meristem as they break through the soil to reach the surface. Once in contact with light, the hook opens and cotyledons are oriented upward and separate. Hook development in the dark after seedling emergence from the seed follows three distinctly timed and sequential phases: formation, maintenance, and eventual opening. We previously identified MISREGULATED IN DARK9 (MIDA9) as a phytochrome interacting factor (PIF)-repressed gene in the dark necessary for hook development during etiolated growth. MIDA9 encodes the type 2C phosphatase PP2C.D1, and pp2c-d1/mida9 mutants exhibit open hooks in the dark. Recent evidence has described that PP2C.D1 and other PP2C.D members negatively regulate SMALL AUXIN UP RNA (SAUR)-mediated cell elongation. However, the fundamental question of the timing of PP2C.D1 action (and possibly other members of the PP2C.D family) during hook development remains to be addressed. Here, we show that PP2C.D1 is required immediately after germination to form the hook. pp2c.d1/mida9 shows reduced cell expansion in the outer layer of the hook and, therefore, does not establish the differential cell growth necessary for hook formation, indicating that PP2C.D1 is necessary to promote cell elongation during this early stage. Additionally, genetic analyses of single and high order mutants in PP2C.D1, PP2C.D2, and PP2C.D5 demonstrate that the three PP2C.Ds act collectively and sequentially during etiolation: whereas PP2C.D1 dominates hook formation, PP2C.D2 is necessary during the maintenance phase, and PP2C.D5 acts to prevent opening during the third phase together with PP2C.D1 and PP2C.D2. Finally, we uncover a possible connection of PP2C.D1 levels with ethylene physiology, which could help optimize hook formation during post-germinative growth in the dark.
PMID: 33767720
Front Plant Sci , IF:4.402 , 2021 , V12 : P635962 doi: 10.3389/fpls.2021.635962
Complex N-Glycans Are Important for Normal Fruit Ripening and Seed Development in Tomato.
Institute of Plant Biology and Biotechnology, University of Munster, Munster, Germany.; Department of Dermatology, University of Munster, Munster, Germany.; Molekulare Pflanzenphysiologie, Department Biologie, Friedrich-Alexander-Universitat Erlangen-Nurnberg, Erlangen, Germany.
Complex N-glycan modification of secretory glycoproteins in plants is still not well understood. Essential in animals, where a lack of complex N-glycans is embryo-lethal, their presence in plants seemed less relevant for a long time mostly because Arabidopsis thaliana cgl1 mutants lacking N-acetyl-glucosaminyltransferase I (GNTI, the enzyme initiating complex N-glycan maturation in the Golgi apparatus) are viable and showed only minor impairments regarding stress tolerance or development. A different picture emerged when a rice (Oryza sativa) gntI T-DNA mutant was found to be unable to reach the reproductive stage. Here, we report on tomato (Solanum lycopersicum) lines that showed severe impairments upon two RNA interference (RNAi) approaches. Originally created to shed light on the role of core alpha1,3-fucose and beta1,2-xylose residues in food allergy, plants with strongly reduced GNTI activity developed necrotic fruit-attached stalks and early fruit drop combined with patchy incomplete ripening. Correspondingly, semiquantitative RT-PCR of the abscission zone (az) revealed an increase of abscission markers. Also, GNTI-RNA interference (RNAi) plants were more susceptible to sporadic infection. To obtain vital tomatoes with comparable low allergenic potential, Golgi alpha-mannosidase II (MANII) was chosen as the second target. The resulting phenotypes were oppositional: MANII-reduced plants carried normal-looking fruits that remained attached for extended time without signs of necrosis. Fruits contained no or only few, but enlarged, seeds. Furthermore, leaves developed rolled-up rims simultaneously during the reproductive stage. Trials to cross MANII-reduced plants failed, while GNTI-reduced plants could be (back-)crossed, retaining their characteristic phenotype. This phenotype could not be overcome by ethephon or indole-3-acetic acid (IAA) application, but the latter was able to mimic patchy fruit ripening in wild-type. Phytohormones measured in leaves and 1-aminocyclopropane-1-carboxylic acid (ACC) contents in fruits showed no significant differences. Together, the findings hint at altered liberation/perception of protein-bound N-glycans, known to trigger auxin-like effects. Concomitantly, semiquantitative RT-PCR analysis revealed differences in auxin-responsive genes, indicating the importance of complex N-glycan modification for hormone signaling/crosstalk. Another possible role of altered glycoprotein life span seems subordinate, as concluded from transient expression of Arabidopsis KORRIGAN KOR1-GFP fusion proteins in RNAi plants of Nicotiana benthamiana. In summary, our analyses stress the importance of complex N-glycan maturation for normal plant responses, especially in fruit-bearing crops like tomato.
PMID: 33767719
Front Plant Sci , IF:4.402 , 2021 , V12 : P632676 doi: 10.3389/fpls.2021.632676
Abscisic Acid Regulates the Root Growth Trajectory by Reducing Auxin Transporter PIN2 Protein Levels in Arabidopsis thaliana.
Laboratory of Photosynthesis and Environment, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.; State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, China.; 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.
The root is in direct contact with soil. Modulation of root growth in response to alterations in soil conditions is pivotal for plant adaptation. Extensive research has been conducted concerning the adjustment of root elongation and architecture in response to environmental factors. However, little is known about the modulation of the root growth trajectory, as well as its hormonal mechanism. Here we report that abscisic acid (ABA) participated in controlling root growth trajectory. The roots upon ABA treatment or from ABA-accumulation double mutant cyp707a1,3 exhibit agravitropism-like growth pattern (wavy growth trajectory). The agravitropism-like phenotype is mainly ascribed to the compromised shootward transportation of auxin since we detected a reduced fluorescence intensity of auxin reporter DR5:VENUS in the root epidermis upon exogenous ABA application or in the endogenous ABA-accumulation double mutant cyp707a1,3. We then tried to decipher the mechanism by which ABA suppressed shootward auxin transport. The membrane abundance of PIN2, a facilitator of shootward auxin transport, was significantly reduced following ABA treatment and in cyp707a1,3. Finally, we revealed that ABA reduced the membrane PIN2 intensity through suppressing the PIN2 expression rather than accelerating PIN2 degradation. Ultimately, our results suggest a pivotal role for ABA in the root growth trajectory and the hormonal interactions orchestrating this process.
PMID: 33763094
Front Plant Sci , IF:4.402 , 2021 , V12 : P621032 doi: 10.3389/fpls.2021.621032
Identifying Molecular Chechkpoints for Adventitious Root Induction: Are We Ready to Fill the Gaps?
Department of Life Sciences, University of Alcala, Alcala de Henares, Spain.
The molecular mechanisms underlying de novo root organogenesis have been under intense study for the last decades. As new tools and resources became available, a comprehensive model connecting the processes and factors involved was developed. Separate phases that allow for specific analyses of individual checkpoints were well defined. Physiological approaches provided information on the importance of metabolic processes and long-distance signaling to balance leaf and stem status and activation of stem cell niches to form new root meristems. The study of plant hormones revealed a series of sequential roles for cytokinin and auxin, dynamically interconnected and modulated by jasmonic acid and ethylene. The identification of genes specifying cell identity uncovered a network of sequentially acting transcriptional regulators that link hormonal control to cell fate respecification. Combined results from herbaceous model plants and the study of recalcitrant woody species underscored the need to understand the limiting factors that determine adventitious rooting competence. The relevance of epigenetic control was emphasized by the identification of microRNAs and chromatin remodeling agents involved in the process. As the different players are set in place and missing pieces become apparent, findings in related processes can be used to identify new candidates to complete the picture. Molecular knobs connecting the balance cell proliferation/differentiation to hormone signaling pathways, transcriptional control of cell fate or metabolic modulation of developmental programs can offer clues to unveil new elements in the dynamics of adventitious rooting regulatory networks. Mechanisms for cell non-autonomous signaling that are well characterized in other developmental processes requiring establishment and maintenance of meristems, control of cell proliferation and cell fate specification can be further explored. Here, we discuss possible candidates and approaches to address or elude the limitations that hinder propagation programs requiring adventitious rooting.
PMID: 33747003
Plant Cell Physiol , IF:4.062 , 2021 Mar , V62 (1) : P166-177 doi: 10.1093/pcp/pcaa150
Cadmium Inhibits Lateral Root Emergence in Rice by Disrupting OsPIN-Mediated Auxin Distribution and the Protective Effect of OsHMA3.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.; State Key Laboratory of Plant Physiology and Biochemistry, College of Life Science, Zhejiang University, Hangzhou 310058, China.
Cadmium (Cd) strongly inhibits root growth, especially the formation of lateral roots (LRs). The mechanism of Cd inhibition on LR formation in rice (Oryza sativa) remains unclear. In this study, we found that LR emergence in rice was inhibited significantly by 1 M Cd and almost completely arrested by 5 M Cd. Cd suppressed both the formation and subsequent development of the lateral root primordium (LRP). By using transgenic rice expressing the auxin response reporters DR5::GUS and DR5rev::VENUS, we found that Cd markedly reduced the auxin levels in the stele and LRP. Cd rapidly downregulated the expression of the auxin efflux transporter genes OsPIN1b, OsPIN1c and OsPIN9 in the stele and LRP. The emergence of LRs in a rice cultivar with a null allele of OsHMA3 (Heavy Metal ATPase 3) was more sensitive to Cd than cultivars with functional alleles. Overexpression of functional OsHMA3 in rice greatly alleviated the inhibitory effect of Cd, but the protective effect of OsHMA3 was abolished by the auxin polar transport inhibitor 1-N-naphthylphthalamic acid. The results suggest that Cd inhibits LR development in rice by disrupting OsPIN-mediated auxin distribution to LRP and OsHMA3 protects against Cd toxicity by sequestering Cd into the vacuoles.
PMID: 33300991
Plant Cell Physiol , IF:4.062 , 2021 Mar , V62 (1) : P3-7 doi: 10.1093/pcp/pcaa134
The Molecular Basis of Age-Modulated Plant De Novo Root Regeneration Decline in Arabidopsis thaliana.
College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
Plants possess a regeneration capacity that enables them to survive after wounding. For example, detached Arabidopsis thaliana leaves are able to form adventitious roots from their cutting sites even in the absence of exogenous hormone supplements, as process termed de novo root regeneration (DNRR). Wounding rapidly induces auxin biosynthesis at the cutting sites and then elicits a signaling cascade to promote cell fate transitions and finally generate the adventitious roots. However, rooting rates in older plants are much lower than in younger leaf explants. In this review, we highlight the recent breakthroughs in the understanding of DNRR decay in older plants from at least two independent signaling routes: (i) via the accumulation of EIN3 protein in older plants, which directly suppresses expression of WUSCHEL RELATED HOMEOBOX (WOX) genes to inhibit rooting; (ii) the miR156-SPLs-AP2/ERFs pathway, which modulates root regeneration by reducing auxin biosynthesis.
PMID: 33079183
Sci Rep , IF:3.998 , 2021 Mar , V11 (1) : P6494 doi: 10.1038/s41598-021-85932-w
Sucrose interferes with endogenous cytokinin homeostasis and expression of organogenesis-related genes during de novo shoot organogenesis in kohlrabi.
Institute for Biological Research "Sinisa Stankovic"-National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11060, Belgrade, Serbia. tatjana@ibiss.bg.ac.rs.; Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojova 263, 16502, Prague 6, Czech Republic.; Institute for Biological Research "Sinisa Stankovic"-National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11060, Belgrade, Serbia.
Cross-talk between phytohormones and sugars is intensely involved in plant metabolism, growth and regeneration. We documented alterations in cytokinin (CK) homeostasis in four developmental stages during de novo shoot organogenesis (DNSO) of kohlrabi (Brassica oleracea var. gongylodes cv. Vienna Purple) seedlings induced by exogenous CKs, trans-zeatin (transZ) and thidiazuron (TDZ), added together with elevated sucrose concentration (6% and 9%). Significant impact of CK and sucrose treatment and their interaction was recorded in all investigated stages, including plantlet development before calli formation (T1 and T2), calli formation (T3) and shoot regeneration (T4). Results showed remarkable increase in total CK levels for transZ treatment, particularly with 9% sucrose. This trend was observed for all physiological and structural groups of CKs. Application of TDZ contributed to little or no increase in CK levels regardless of sucrose concentration. Analysis of expression profiles of organogenesis-related genes involved in auxin transport, CK response, shoot apical meristem formation and cell division revealed that higher sugar concentration significantly downregulated the analysed genes, particularly in T3. This continued on TDZ, but transZ induced an opposite effect with 9% sucrose in T4, increasing gene activity. Our results demonstrated that phytohormone metabolism might be triggered by sucrose signalling in kohlrabi DNSO.
PMID: 33753792
Sci Rep , IF:3.998 , 2021 Mar , V11 (1) : P6359 doi: 10.1038/s41598-021-85886-z
Comparative transcriptome analysis during developmental stages of direct somatic embryogenesis in Tilia amurensis Rupr.
Department of Forest Bio-Resources, National Institute of Forest Science, Suwon, 13361, Republic of Korea.; Department of Agriculture, Forestry and Bioresources, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea.; Department of Agriculture, Forestry and Bioresources, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea. kangks84@snu.ac.kr.; Department of Biological Sciences, Chungnam National University, Daejeon, 34134, Republic of Korea. shim.donghwan@gmail.com.
Tilia species are valuable woody species due to their beautiful shape and role as honey trees. Somatic embryogenesis can be an alternative method for mass propagation of T. amurensis. However, the molecular mechanisms of T. amurensis somatic embryogenesis are yet to be known. Here, we conducted comparative transcriptional analysis during somatic embryogenesis of T. amurensis. RNA-Seq identified 1505 differentially expressed genes, including developmental regulatory genes. Auxin related genes such as YUC, AUX/IAA and ARF and signal transduction pathway related genes including LEA and SERK were differentially regulated during somatic embryogenesis. Also, B3 domain family (LEC2, FUS3), VAL and PKL, the regulatory transcription factors, were differentially expressed by somatic embryo developmental stages. Our results could provide plausible pathway of signaling somatic embryogenesis of T. amurensis, and serve an important resource for further studies in direct somatic embryogenesis in woody plants.
PMID: 33737673
Sci Rep , IF:3.998 , 2021 Mar , V11 (1) : P5537 doi: 10.1038/s41598-021-85147-z
Molecular characterization of Fe-acquisition genes causing decreased Fe uptake and photosynthetic inefficiency in Fe-deficient sunflower.
Department of Botany, University of Rajshahi, Rajshahi, 6205, Bangladesh. ahmad.kabir@ru.ac.bd.; Department of Botany, University of Rajshahi, Rajshahi, 6205, Bangladesh.; Department of Genetics, Faculty of Agriculture, Alexandria University Alexandria, Alexandria, Egypt.; Department of Biotechnology, College of Science, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia.
Iron (Fe) deficiency in plants hinders growth and yield. Thus, this study aims to elucidate the responses and molecular characterization of genes in Fe-deficient sunflower. The study was conducted on 14 days-old sunflower plants cultivated in hydroponic culture under Fe-sufficient and Fe-deficient conditions. The Fe-starved sunflower showed substantial decrease in plant biomass, SPAD score, quantum yield efficiency of PSII (Fv/Fm), photosynthetic performance index (Pi_ABS). Further, Fe shortage reduced Fe and Zn concentrations in roots and shoots, accompanied by a marked decrease of HaNramp1 and HaZIP1 expression in roots, suggesting the association of Zn status contributing to photosynthetic inefficiency in sunflower. The ferric chelate reductase (FCR) activity, along with HaFRO2 and HaIRT1 transcripts, were constitutively expressed, suggesting that sunflower plants can regulate FCR activity, although the lack of bioavailable Fe in the rhizosphere strongly corresponds to the limited Fe uptake in sunflower. The substantial increase of proton extrusion in roots and the localization of Fe-related genes in the plasma membrane are also evident in sunflower as common responses to Fe-deficiency by this Strategy I plant species. Analysis showed that three motifs of Fe-related proteins were linked to the ZIP zinc transporter. The interactome map revealed the close partnership of these Fe-related genes in addition to FRU gene encoding putative transcription factor linked to Fe uptake response. The cis-regulatory analysis of promoter suggested the involvement of auxin, salicylic acid, and methyl jasmonate-responsive elements in the regulatory process in response to Fe deficiency. These findings may be beneficial to develop Fe-efficient sunflower plants through breeding or genome editing approaches.
PMID: 33692433
Plant Cell Rep , IF:3.825 , 2021 Mar doi: 10.1007/s00299-021-02680-x
The SlTCP26 promoting lateral branches development in tomato.
Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong, 637009, Sichuan, China.; Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), College of Life Science, China West Normal University, Nanchong, 637009, Sichuan, China. zoujian@cwnu.edu.cn.
KEY MESSAGE: The SlTCP26 negatively regulated auxin signal to relieve the apical dominance and suppressed abscisic acid signal to remove the lateral bud dormancy, promoting lateral branches development. Lateral branches formation from lateral buds is a complex regulatory process in higher plants, and the interaction between transcription factors and hormones is indispensable during this process. TCP transcription factors have been reported to regulate lateral branches development, while the detailed function, especially interacting with auxin and ABA during this process, was still ambiguous in tomato. In this study, a branch regulatory gene, SlTCP26, was identified in tomato, and its role along with its interaction to hormones during branch development, as investigated. The results indicated that overexpression of SlTCP26 would promote lateral branches development, and could suppress the expressing of the genes associated with IAA signaling, presenting similar effects in decapitated plants. Conversely, the exogenous IAA application could inhibit the expression of SlTCP26. Furthermore, the expressing of the ABA signaling-related genes was inhibited in SlTCP26 overexpressed tomato, similar to that in decapitated tomato. Our findings suggested that SlTCP26 may be a crucial adjuster for synergistic action between ABA and IAA signals during the development of lateral branches, and it could promote the lateral buds grow into lateral shoots, via inhibiting IAA signal to relieve the apical dominance and suppressing ABA signal to remove the lateral bud dormancy. Our study provided some insights for the development of tomato lateral branches to understand the apical dominance regulatory network.
PMID: 33758995
Plant Cell Rep , IF:3.825 , 2021 Mar doi: 10.1007/s00299-021-02683-8
Phytohormone signaling and crosstalk in regulating drought stress response in plants.
DST-INSPIRE Faculty, Agriculture Biotechnology Department, National Agri-Food Biotechnology Institute, Sector 81, Sahibzada Ajit Singh Nagar, Mohali, 140308, Punjab, India. salvi.prafull@gmail.com.; National Institute of Plant Genome Research, New Delhi, India.; ICAR-National Institute for Plant Biotechnology, New Delhi, India.; DST-INSPIRE Faculty, Agriculture Biotechnology Department, National Agri-Food Biotechnology Institute, Sector 81, Sahibzada Ajit Singh Nagar, Mohali, 140308, Punjab, India.; Department of Biotechnology, Shree Ramkrishna Institute of Computer Education and Applied Sciences, Veer Narmad South Gujarat University, Surat, Gujarat, India.; Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India.
Phytohormones are ubiquitously involved in plant biological processes and regulate cellular signaling pertaining to unheralded environmental cues, such as salinity, drought, extreme temperature and nutrient deprivation. The association of phytohormones to nearly all the fundamental biological processes epitomizes the phytohormone syndicate as a candidate target for consideration during engineering stress endurance in agronomically important crops. The drought stress response is essentially driven by phytohormones and their intricate network of crosstalk, which leads to transcriptional reprogramming. This review is focused on the pivotal role of phytohormones in water deficit responses, including their manipulation for mitigating the effect of the stressor. We have also discussed the inherent complexity of existing crosstalk accrued among them during the progression of drought stress, which instigates the tolerance response. Therefore, in this review, we have highlighted the role and regulatory aspects of various phytohormones, namely abscisic acid, auxin, gibberellic acid, cytokinin, brassinosteroid, jasmonic acid, salicylic acid, ethylene and strigolactone, with emphasis on drought stress tolerance.
PMID: 33751168
Plant Physiol Biochem , IF:3.72 , 2021 Mar , V162 : P634-646 doi: 10.1016/j.plaphy.2021.03.030
The PIN gene family in relic plant L. chinense: Genome-wide identification and gene expression profiling in different organizations and abiotic stress responses.
Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China.; College of Horticulture Technology, Suzhou Agricultural Vocational and Technical College, Suzhou, 215000, China.; Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China. Electronic address: chenjh@njfu.edu.cn.
The auxin efflux carrier PIN-FORMED (PIN) proteins are required for the polar transport of auxin between cells through their asymmetric distribution on the plasma membrane, thus mediating the differential distribution of auxin in plants, finally, affecting plant growth and developmental processes. In this study, 11 LcPIN genes were identified. The structural characteristics and evolutionary status of LcPIN genes were thoroughly investigated and interpreted combining physicochemical property analysis, evolutionary analysis, gene structure analysis, chromosomal localization, etc. Multi-species protein sequence analysis showed that angiosperm PIN genes have strong purification options and some functional sites were predicted about PIN protein polarity, trafficking and activity in L. chinense. Further qRT-PCR and transcriptome data analysis indicated that the long LcPINs have highly expressed from globular embryo to plantlet, and the LcPIN6a started upregulated in cotyledon embryo. The LcPIN3 and LcPIN6a are both highly expressed during the development of stamens and petals and the expression of LcPIN2 is related to root elongation, suggesting that they may play an important role in these processes. Experiment data indicates that LcPIN5 and LcPIN8 might play a key role in auxin transport in Liriodendron stems and leaves under abiotic stress. Analyzed the response of LcPIN genes to abiotic stress and as a basis for uncovering the biological role of LcPIN genes in development and adaption to adverse environments. This study provides a foundation for further genetic and functional analyses.
PMID: 33774468
Plant Physiol Biochem , IF:3.72 , 2021 Mar , V162 : P531-546 doi: 10.1016/j.plaphy.2021.02.046
Physiological, biochemical, and transcriptional regulation in a leguminous forage Trifolium pratense L. responding to silver ions.
School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: 402163339@qq.com.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: iamlhb@126.com.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: lihaibo@mail.neu.edu.cn.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: chenxineu@mail.neu.edu.cn.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: 1031168439@qq.com.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: lizhe1824@163.com.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: 15111075278@163.com.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: 1920845124@qq.com.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: 1870886@stu.neu.edu.cn.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: 2890821067@qq.com.; School of Resources and Civil Engineering, Northeastern University, 11 Wenhua Road, Heping District, Shenyang, 110819, China. Electronic address: 1039919074@qq.com.
Trifolium pratense L. (red clover) is an important leguminous crop with great potential for Ag-contaminated environment remediation. Whereas, the molecular mechanisms of Ag tolerance in red clover are largely unknown. Red clover seedlings were used for physiological and transcriptomic investigation under 0, 20, 50, and 100mg/L Ag(+) stress in our research to reveal potential molecular resistance mechanism. Research showed that red clover possessed fairly strong Ag absorbance capacity, the Ag level reached 0.14 and 2.35mg/g.FW in the leaves and roots under 100mg/L AgNO3 stress condition. Root fresh weight, root dry weight, root water content, and photosynthetic pigments contents were significantly decreased with elevating AgNO3 concentration. Obvious withered plant tissue, microstructure disorder, and disrupted organelles were observed. In vitro evaluations (e.g., PI and DCFH-DA staining) represented that AgNO3 at high concentration (100mg/L) exhibited obvious inhibition on cell viability, which was due possibly to the induction of reactive oxygen species (ROS) accumulation. A total of 44643 differentially expressed genes (DEGs) were identified under Ag stress, covering 27155 upregulated and 17488 downregulated genes. 12 stress-responsive DEGs was authenticated utilizing real-time quantitative PCR (qRT-PCR). Gene ontology (GO) analysis revealed that the DEGs were mostly related to metal ion binding (molecular function), nucleus (cellular component), and defense response (biological process). Involved DEGs in sequence-specific DNA binding transcription factor activity, response to various hormones (e.g., abscisic acid, IAA/Auxin, salicylic acid, and etc), calcium signal transduction, and protein ubiquitination were concluded to play crucial roles in Ag tolerance of red clover. On the other hand, Kyoto Encyclopedia of Genes and Genomes (KEGG) database annotated several stress responsive pathways such as plant-pathogen interaction, phenylpropanoid biosynthesis, ubiquitin mediated proteolysis, hormone signal transduction, and autophagy. Several down-regulated genes (e.g., RSF2, RCD1, DOX1, and etc) were identified indicating possible metabolic disturbance. Besides, protein-protein interaction network (PPI) identified several pivotal genes such as ribosomal proteins, TIR, and ZAT.
PMID: 33773229
Plant Physiol Biochem , IF:3.72 , 2021 Mar , V162 : P447-455 doi: 10.1016/j.plaphy.2021.03.013
Effects of graphene oxide on tomato growth in different stages.
School of Life Sciences, Shanxi Datong University, Datong, 037009, China.; Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China. Electronic address: jgzhaoshi@163.com.; School of Physics and Optoelectronic Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.; Department of Biotechnology, Mohi-ud-Din Islamic University, Nerian Sharif, 12080, AJ&K, Pakistan.
The nano-carbon graphene has unique structural and physicochemical properties, which are conducive to various biomedical applications. We assessed the effect of graphene oxide (GO) on tomato plants at the seedling and mature stages in terms of morphological and biochemical indices. GO treatment significantly improved the shoot/stem growth of tomato in a dose-dependent manner by increasing the cortical cells number, cross-sectional area, diameter and vascular-column area. In addition, GO also promoted the morphological development of the root system and increased biomass accumulation. The surface area of root tips and hairs of tomato plants treated with 50 mg/L and 100 mg/L GO were significantly greater compared to the untreated control. At the molecular level, GO induced the expression of root development-related genes (SlExt1 and LeCTR1) and inhibited the auxin-responsive gene (SlIAA3). However, 50 mg/L and 100 mg/L GO significantly increased the root auxin content, which in turn increased the number of fruits and hastened fruit ripening compared to the control plants. Taken together, GO can improve the tomato growth when used at the appropriate concentration, and is a promising nano-carbon material for agricultural use.
PMID: 33740683
BMC Genomics , IF:3.594 , 2021 Mar , V22 (1) : P202 doi: 10.1186/s12864-021-07504-6
Characterization of cotton ARF factors and the role of GhARF2b in fiber development.
National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research, Institute of Plant Physiology and Ecology/CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.; Plant Stress Biology Center, Institute of Plant Physiology and Ecology/CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.; University of Chinese Academy of Sciences, Shanghai, 200032, China.; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.; Esquel Group, 25 Harbour Road, Wanchai, Hong Kong, China.; National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research, Institute of Plant Physiology and Ecology/CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China. b1301031@cau.edu.cn.; Institute of Carbon Materials Science, Shanxi Datong University, Datong, 037009, China. b1301031@cau.edu.cn.
BACKGROUND: Cotton fiber is a model system for studying plant cell development. At present, the functions of many transcription factors in cotton fiber development have been elucidated, however, the roles of auxin response factor (ARF) genes in cotton fiber development need be further explored. RESULTS: Here, we identify auxin response factor (ARF) genes in three cotton species: the tetraploid upland cotton G. hirsutum, which has 73 ARF genes, and its putative extent parental diploids G. arboreum and G. raimondii, which have 36 and 35 ARFs, respectively. Ka and Ks analyses revealed that in G. hirsutum ARF genes have undergone asymmetric evolution in the two subgenomes. The cotton ARFs can be classified into four phylogenetic clades and are actively expressed in young tissues. We demonstrate that GhARF2b, a homolog of the Arabidopsis AtARF2, was preferentially expressed in developing ovules and fibers. Overexpression of GhARF2b by a fiber specific promoter inhibited fiber cell elongation but promoted initiation and, conversely, its downregulation by RNAi resulted in fewer but longer fiber. We show that GhARF2b directly interacts with GhHOX3 and represses the transcriptional activity of GhHOX3 on target genes. CONCLUSION: Our results uncover an important role of the ARF factor in modulating cotton fiber development at the early stage.
PMID: 33752589
BMC Genomics , IF:3.594 , 2021 Mar , V22 (1) : P185 doi: 10.1186/s12864-021-07450-3
A study of the heterochronic sense/antisense RNA representation in florets of sexual and apomictic Paspalum notatum.
Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR-CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, (S2125ZAA) Zavalla, Santa Fe, Argentina.; Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR-CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, (S2125ZAA) Zavalla, Santa Fe, Argentina. pessino@arnet.com.ar.
BACKGROUND: Apomixis, an asexual mode of plant reproduction, is a genetically heritable trait evolutionarily related to sexuality, which enables the fixation of heterozygous genetic combinations through the development of maternal seeds. Recently, reference floral transcriptomes were generated from sexual and apomictic biotypes of Paspalum notatum, one of the most well-known plant models for the study of apomixis. However, the transcriptome dynamics, the occurrence of apomixis vs. sexual expression heterochronicity across consecutive developmental steps and the orientation of transcription (sense/antisense) remain unexplored. RESULTS: We produced 24 Illumina TruSeq(R)/ Hiseq 1500 sense/antisense floral transcriptome libraries covering four developmental stages (premeiosis, meiosis, postmeiosis, and anthesis) in biological triplicates, from an obligate apomictic and a full sexual genotype. De novo assemblies with Trinity yielded 103,699 and 100,114 transcripts for the apomictic and sexual samples respectively. A global comparative analysis involving reads from all developmental stages revealed 19,352 differentially expressed sense transcripts, of which 13,205 (68%) and 6147 (32%) were up- and down-regulated in apomictic samples with respect to the sexual ones. Interestingly, 100 differentially expressed antisense transcripts were detected, 55 (55%) of them up- and 45 (45%) down-regulated in apomictic libraries. A stage-by-stage comparative analysis showed a higher number of differentially expressed candidates due to heterochronicity discrimination: the highest number of differential sense transcripts was detected at premeiosis (23,651), followed by meiosis (22,830), postmeiosis (19,100), and anthesis (17,962), while the highest number of differential antisense transcripts were detected at anthesis (495), followed by postmeiosis (164), meiosis (120) and premeiosis (115). Members of the AP2, ARF, MYB and WRKY transcription factor families, as well as the auxin, jasmonate and cytokinin plant hormone families appeared broadly deregulated. Moreover, the chronological expression profile of several well-characterized apomixis controllers was examined in detail. CONCLUSIONS: This work provides a quantitative sense/antisense gene expression catalogue covering several subsequent reproductive developmental stages from premeiosis to anthesis for apomictic and sexual P. notatum, with potential to reveal heterochronic expression between reproductive types and discover sense/antisense mediated regulation. We detected a contrasting transcriptional and hormonal control in apomixis and sexuality as well as specific sense/antisense modulation occurring at the onset of parthenogenesis.
PMID: 33726667
BMC Genomics , IF:3.594 , 2021 Mar , V22 (1) : P183 doi: 10.1186/s12864-021-07501-9
Transcriptomes analysis reveals novel insight into the molecular mechanisms of somatic embryogenesis in Hevea brasiliensis.
Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, No.4 Xueyuan Road, Haikou, 571101, China.; School of Life and Pharmaceutical Sciences, Hainan University, Haikou, 570228, China.; Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, No.4 Xueyuan Road, Haikou, 571101, China. shqpeng@163.com.; Hainan Academy of Tropical Agricultural Resource, CATAS, Haikou, 571101, China. shqpeng@163.com.
BACKGROUND: Somatic embryogenesis (SE) is a promising technology for plant vegetative propagation, which has an important role in tree breeding. Though rubber tree (Hevea brasiliensis Muell. Arg.) SE has been founded, few late SE-related genes have been identified and the molecular regulation mechanisms of late SE are still not well understood. RESULTS: In this study, the transcriptomes of embryogenic callus (EC), primary embryo (PE), cotyledonary embryo (CE), abnormal embryo (AE), mature cotyledonary embryo (MCE) and withered abnormal embryo (WAE) were analyzed. A total of 887,852,416 clean reads were generated, 85.92% of them were mapped to the rubber tree genome. The de novo assembly generated 36,937 unigenes. The differentially expressed genes (DEGs) were identified in the pairwise comparisons of CE vs. AE and MCE vs. WAE, respectively. The specific common DEGs were mainly involved in the phytohormones signaling pathway, biosynthesis of phenylpropanoid and starch and sucrose metabolism. Among them, hormone signal transduction related genes were significantly enriched, especially the auxin signaling factors (AUX-like1, GH3.1, SAUR32-like, IAA9-like, IAA14-like, IAA27-like, IAA28-like and ARF5-like). The transcription factors including WRKY40, WRKY70, MYBS3-like, MYB1R1-like, AIL6 and bHLH93-like were characterized as molecular markers for rubber tree late SE. CML13, CML36, CAM-7, SERK1 and LEAD-29-like were also related to rubber tree late SE. In addition, histone modification had crucial roles during rubber tree late SE. CONCLUSIONS: This study provides important information to elucidate the molecular regulation during rubber tree late SE.
PMID: 33711923
Plant Sci , IF:3.591 , 2021 May , V306 : P110874 doi: 10.1016/j.plantsci.2021.110874
PpEBB1 directly binds to the GCC box-like element of auxin biosynthesis related genes.
College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271000, China; State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong, 271000, China; Shandong Collaborative Innovation Center for Fruit & Vegetable Production With High Quality and Efficiency, Tai'an, Shandong, 271000, China.; Shandong Academy of Agricultural Sciences, Jinan, Shandong, 250100, China.; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271000, China; State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong, 271000, China; Shandong Collaborative Innovation Center for Fruit & Vegetable Production With High Quality and Efficiency, Tai'an, Shandong, 271000, China. Electronic address: liling217@sdau.edu.cn.; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271000, China; State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong, 271000, China; Shandong Collaborative Innovation Center for Fruit & Vegetable Production With High Quality and Efficiency, Tai'an, Shandong, 271000, China. Electronic address: xilingfu@sdau.edu.cn.
EARLY BUD-BREAK 1 (EBB1) can promote bud break, and this function is likely conserved in woody plants. To get a more comprehensive understand of its function, peach (Prunus persica var. nectarina cultivar Zhongyou 4) PpEBB1 was overexpressed in Arabidopsis; the resultant phenotypes, including curved leaves, abnormal development of floral organs and low seed set, were similar to those of DORNROSCHEN-LIKE (DRNL) overexpression, indicating that PpEBB1 was a putative ortholog of AtDRNL. PpEBB1 bound to the GCC box-like element in the STYLISH1/SHI RELATED SEQUENCE5 (STY1/SRS5) promoter of peach, which has been proposed to occur in Arabidopsis as well. A GCC box-like element was also found in the YUCCA1 (YUC1) promoter, and PpEBB1 could bind to this element and activate the expression of YUC1. In addition to the elevated auxin content in the PpEBB1-oe plants as observed in our previous study, these results suggest that PpEBB1 can regulate auxin biosynthesis by directly activating related genes. Besides, we screened a zinc finger RING-finger protein, MYB30-INTERACTING E3 LIGASE 1 (PpMIEL1), showing interaction with PpEBB1, suggesting that the stability of PpEBB1 might be influenced by PpMIEL1 through ubiquitination.
PMID: 33775370
J Proteomics , IF:3.509 , 2021 Mar , V236 : P104126 doi: 10.1016/j.jprot.2021.104126
New insight into the rapid growth of the Mikania micrantha stem based on DIA proteomic and RNA-Seq analysis.
School of Life Sciences, Sun Yat-sen University, Xingang Xi Lu 135, Guangzhou 510275, China.; School of Life Sciences, Sun Yat-sen University, Xingang Xi Lu 135, Guangzhou 510275, China; Research Institute of Sun Yat-sen University in Shenzhen, Shenzhen 518057, Shenzhen 518057, China. Electronic address: suyj@mail.sysu.edu.cn.; College of Life Sciences, South China Agricultural University, Wushan 483, Guangzhou 510642, China. Electronic address: tingwang@scau.edu.cn.
Mikania micrantha is one of the world's most invasive plants, which causes severe damage to natural ecosystems and agroforestry systems due to its rapid stem growth. This work investigated the proteomic and transcriptomic profiles of M. micrantha in different stem tissues (pre-internode, post-internode, and internode), as well as in adventitious roots and primary roots with the final goal of elucidating differentially expressed genes and proteins responsible for the rapid growth of stem. The objective was approached by using DIA-based proteomic and RNA-Seq technologies. More than seven giga-transcriptome clean reads were sequenced, and 5196 protein species were identified. Differentially expressed genes identified in all stem tissues were significantly enriched in photosynthesis and carbon fixation, suggesting that the stem possesses a strong photosynthetic capacity in order to maintain the energy supply for this species. Analysis of differentially expressed proteins showed that proteins related to photosystem I/II and the cytochrome b6/f complex, such as D1, D2, and cp43, were also highly accumulated in the adventitious roots, corroborating the transcriptome analysis results. These results provided basic proteomic and transcriptional expression information about the M. micrantha stem and adventitious root, thereby improving our understanding of the molecular mechanism underlying rapid growth in this species. SIGNIFICANCE: This is the first study to investigate the proteomic and transcriptomic profiles of Mikania micrantha, a highly invasive plant, in different stem tissues (pre-internode, post-internode, and internode), as well as in adventitious and primary roots, using the latest DIA-based (data-independent acquisition mode) proteomic and RNA-Seq technologies. A comprehensive study was carried out, and differentially expressed genes and differentially expressed proteins identified in the pre-internode, post-internode, and internode tissues were significantly enriched during photosynthesis and carbon fixation, suggesting that the M. micrantha stem possesses a strong photosynthetic capacity that allows the plant to maintain a high energy supply. Enriched plant hormone signal transduction pathway analysis revealed an interaction between auxin and other phytohormones involved in adventitious root development. The study provided basic data on the molecular mechanism of M. micrantha vegetative propagation and the rapid growth of its stem. The novel scientific content of this study successfully builds upon the limited information currently available on the subject, therefore warranting publication.
PMID: 33540067
BMC Plant Biol , IF:3.497 , 2021 Mar , V21 (1) : P145 doi: 10.1186/s12870-021-02922-w
Identification of regulatory factors promoting embryogenic callus formation in barley through transcriptome analysis.
Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics and Regenerative Biology, College of Life Sciences, Zhejiang University, Zhejiang, 310058, Hangzhou, China.; Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics and Regenerative Biology, College of Life Sciences, Zhejiang University, Zhejiang, 310058, Hangzhou, China. ninghan@zju.edu.cn.
BACKGROUND: Barley is known to be recalcitrant to tissue culture, which hinders genetic transformation and its biotechnological application. To date, the ideal explant for transformation remains limited to immature embryos; the mechanism underlying embryonic callus formation is elusive. RESULTS: This study aimed to uncover the different transcription regulation pathways between calli formed from immature (IME) and mature (ME) embryos through transcriptome sequencing. We showed that incubation of embryos in an auxin-rich medium caused dramatic changes in gene expression profiles within 48 h. Overall, 9330 and 11,318 differentially expressed genes (DEGs) were found in the IME and ME systems, respectively. 3880 DEGs were found to be specific to IME_0h/IME_48h, and protein phosphorylation, regulation of transcription, and oxidative-reduction processes were the most common gene ontology categories of this group. Twenty-three IAA, fourteen ARF, eight SAUR, three YUC, and four PIN genes were found to be differentially expressed during callus formation. The effect of callus-inducing medium (CIM) on IAA genes was broader in the IME system than in the ME system, indicating that auxin response participates in regulating cell reprogramming during callus formation. BBM, LEC1, and PLT2 exhibited a significant increase in expression levels in the IME system but were not activated in the ME system. WUS showed a more substantial growth trend in the IME system than in the ME system, suggesting that these embryonic, shoot, and root meristem genes play crucial roles in determining the acquisition of competency. Moreover, epigenetic regulators, including SUVH3A, SUVH2A, and HDA19B/703, exhibited differential expression patterns between the two induction systems, indicating that epigenetic reprogramming might contribute to gene expression activation/suppression in this process. Furthermore, we examined the effect of ectopic expression of HvBBM and HvWUS on Agrobacterium-mediated barley transformation. The transformation efficiency in the group expressing the PLTPpro:HvBBM + Axig1pro:HvWUS construct was increased by three times that in the control (empty vector) because of enhanced plant regeneration capacity. CONCLUSIONS: We identified some regulatory factors that might contribute to the differential responses of the two explants to callus induction and provide a promising strategy to improve transformation efficiency in barley.
PMID: 33740900
BMC Plant Biol , IF:3.497 , 2021 Mar , V21 (1) : P126 doi: 10.1186/s12870-021-02904-y
QTLs and candidate genes analyses for fruit size under domestication and differentiation in melon (Cucumis melo L.) based on high resolution maps.
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.; Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China.; Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China.; National Center for Gene Research, CAS Center for Excellence in Molecular Plant Sciences, Shanghai, 200000, China.; Shenyang Agricultural University, College of Horticulture, Shenyang, 110866, China.; Design Gollege, Zhoukou Normal University, Zhoukou, 466000, China.; Centre for Research in Agricultural Genomics CSIC-IRTA-UAB-UB, Barcelona, Spain.; Institut de Recerca i Tecnologia Agroalimentaries (IRTA), Barcelona, Spain.; Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China. Zhaoguangwei@caas.cn.; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081, Beijing, China. wanghuaisong06@sina.com.
BACKGROUND: Melon is a very important horticultural crop produced worldwide with high phenotypic diversity. Fruit size is among the most important domestication and differentiation traits in melon. The molecular mechanisms of fruit size in melon are largely unknown. RESULTS: Two high-density genetic maps were constructed by whole-genome resequencing with two F2 segregating populations (WAP and MAP) derived from two crosses (cultivated agrestis x wild agrestis and cultivated melo x cultivated agrestis). We obtained 1,871,671 and 1,976,589 high quality SNPs that show differences between parents in WAP and MAP. A total of 5138 and 5839 recombination events generated 954 bins in WAP and 1027 bins in MAP with the average size of 321.3 Kb and 301.4 Kb respectively. All bins were mapped onto 12 linkage groups in WAP and MAP. The total lengths of two linkage maps were 904.4 cM (WAP) and 874.5 cM (MAP), covering 86.6% and 87.4% of the melon genome. Two loci for fruit size were identified on chromosome 11 in WAP and chromosome 5 in MAP, respectively. An auxin response factor and a YABBY transcription factor were inferred to be the candidate genes for both loci. CONCLUSION: The high-resolution genetic maps and QTLs analyses for fruit size described here will provide a better understanding the genetic basis of domestication and differentiation, and provide a valuable tool for map-based cloning and molecular marker assisted breeding.
PMID: 33658004
Planta , IF:3.39 , 2021 Mar , V253 (4) : P78 doi: 10.1007/s00425-021-03595-3
Rhizosphere microorganisms enhance in vitro root and plantlet development of Pyrus and Prunus rootstocks.
IRTA Postharvest Programme, Edifici Fruitcentre, Parc Cientific I Tecnologic Agroalimentari de Lleida, 25003, Lleida, Catalonia, Spain.; IRTA Plant In Vitro Culture Laboratory, Fruticulture Programme, Parc Cientific I Tecnologic Agroalimentari de Lleida, 25003, Lleida, Catalonia, Spain.; IRTA Plant In Vitro Culture Laboratory, Fruticulture Programme, Parc Cientific I Tecnologic Agroalimentari de Lleida, 25003, Lleida, Catalonia, Spain. ramon.dolcet@irta.cat.
MAIN CONCLUSION: The in vitro application of rhizosphere microorganisms led to a higher rooting percentage in Pyrus Py12 rootstocks and increased plant growth of Pyrus Py170 and Prunus RP-20. The rooting of fruit tree rootstocks is the most challenging step of the in vitro propagation process. The use of rhizosphere microorganisms to promote in vitro rooting and plant growth as an alternative to the addition of chemical hormones to culture media is proposed in the present study. Explants from two Pyrus (Py170 and Py12) rootstocks and the Prunus RP-20 rootstock were inoculated with Pseudomonas oryzihabitans PGP01, Cladosporium ramotenellum PGP02 and Phoma sp. PGP03 following two different methods to determine their effects on in vitro rooting and plantlet growth. The effects of the microorganisms on the growth of fully developed Py170 and RP-20 plantlets were also studied in vitro. All experiments were conducted using vermiculite to simulate a soil system in vitro. When applied to Py12 shoots, which is a hard-to-root plant material, both C. ramotenellum PGP02 and Phoma sp. PGP03 fungi were able to increase the rooting percentage from 56.25% to 100% following auxin indole-3-butyric acid (IBA) treatment. Thus, the presence of these microorganisms clearly improved root development, inducing a higher number of roots and causing shorter roots. Better overall growth and improved stem growth of treated plants was observed when auxin treatment was replaced by co-culture with microorganisms. A root growth-promoting effect was observed on RP-20 plantlets after inoculation with C. ramotenellum PGP02, while P. oryzihabitans PGP01 increased root numbers for both Py170 and RP-20 and increased root growth over stem growth for RP-20. It was also shown that the three microorganisms P. oryzihabitans PGP01, C. ramotenellum PGP02 and Phoma sp. PGP03 were able to naturally produce auxin, including indole-3-acetic acid (IAA), at different levels. Overall, our results demonstrate that the microorganisms P. oryzihabitans PGP01 and C. ramotenellum PGP02 had beneficial effects on in vitro rooting and plantlet growth and could be applied to in vitro tissue culture as a substitute for IBA.
PMID: 33715081
Front Genet , IF:3.258 , 2021 , V12 : P590830 doi: 10.3389/fgene.2021.590830
Comparative Transcriptome Analysis of Early- and Late-Bolting Traits in Chinese Cabbage (Brassica rapa).
Institute of Horticulture, Henan Academy of Agricultural Sciences, Zhengzhou, China.; Department of Genetics and Plant Breeding, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
Chinese cabbage is one of the most important and widely consumed vegetables in China. The developmental transition from the vegetative to reproductive phase is a crucial process in the life cycle of flowering plants. In spring-sown Chinese cabbage, late bolting is desirable over early bolting. In this study, we analyzed double haploid (DH) lines of late bolting ("Y410-1" and "SY2004") heading Chinese cabbage (Brassica rapa var. pekinensis) and early-bolting Chinese cabbage ("CX14-1") (B. rapa ssp. chinensis var. parachinensis) by comparative transcriptome profiling using the Illumina RNA-seq platform. We assembled 721.49 million clean high-quality paired-end reads into 47,363 transcripts and 47,363 genes, including 3,144 novel unigenes. There were 12,932, 4,732, and 4,732 differentially expressed genes (DEGs) in pairwise comparisons of Y410-1 vs. CX14-1, SY2004 vs. CX14-1, and Y410-1 vs. SY2004, respectively. The RNA-seq results were confirmed by reverse transcription quantitative real-time PCR (RT-qPCR). A Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DEGs revealed significant enrichment for plant hormone and signal transduction as well as starch and sucrose metabolism pathways. Among DEGs related to plant hormone and signal transduction, six unigenes encoding the indole-3-acetic acid-induced protein ARG7 (BraA02g009130), auxin-responsive protein SAUR41 (BraA09g058230), serine/threonine-protein kinase BSK11 (BraA07g032960), auxin-induced protein 15A (BraA10g019860), and abscisic acid receptor PYR1 (BraA08g012630 and BraA01g009450), were upregulated in both late bolting Chinese cabbage lines (Y410-1 and SY2004) and were identified as putative candidates for the trait. These results improve our understanding of the molecular mechanisms underlying flowering in Chinese cabbage and provide a foundation for studies of this key trait in related species.
PMID: 33747036
J Plant Physiol , IF:3.013 , 2021 Mar , V260 : P153405 doi: 10.1016/j.jplph.2021.153405
Auxin and cytokinin mediated regulation involved in vitro organogenesis of papaya.
Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address: zxb1344@126.com.; Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Electronic address: jinjins2@illinois.edu.; Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address: qxzeng0914@163.com.; Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address: Yaying123@yeah.net.; Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address: 1853706201@qq.com.; Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address: 1315971490@qq.com.; Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address: dengban0707@163.com.; Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China. Electronic address: relaxljliu@sina.com.; College of Life Science, Fujian Normal University, Fuzhou 350117, Fujian, China. Electronic address: jinphia@163.com.; Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address: lipingzuo@126.com.; Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address: jingjingyue11@126.com.
In vitro organogenesis is a multistep process which is largely controlled by the balance between auxin and cytokinin. Previous studies revealed a complex network regulating in vitro organogenesis in Arabidopsis thaliana; however, our knowledge of the molecular mechanisms underlying de novo shoot formation in papaya (Carica papaya) remains limited. Here, we optimized multiple factors to achieve an efficient and reproducible protocol for the induction of papaya callus formation and shoot regeneration. Subsequently, we analyzed the dynamic transcriptome profiles of samples undergoing this process, identified 5381, 642, 4047, and 2386 differentially expressed genes (DEGs), including 447, 66, 350, and 263 encoding transcription factors (TFs), in four stage comparisons. The DEGs were mainly involved in phytohormone modulation and transduction processes, particularly for auxin and cytokinin. Of these, 21 and 7 candidate genes involved in the auxin and cytokinin pathways, respectively, had distinct expression patterns throughout in vitro organogenesis. Furthermore, we found two genes encoding key TFs, CpLBD19 and CpESR1, were sharply induced on callus induction medium and shoot induction medium, indicating these two TFs may serve as proxies for callus induction and shoot formation in papaya. We therefore report a regulatory network of auxin and cytokinin signaling in papaya according to the one previously modeled for Arabidopsis. Our comprehensive analyses provide insight into the early molecular regulation of callus initiation and shoot formation in papaya, and are useful for the further identification of the regulators governing in vitro organogenesis.
PMID: 33743435
Biochem Biophys Res Commun , IF:2.985 , 2021 Mar , V553 : P44-50 doi: 10.1016/j.bbrc.2021.03.006
Arabidopsis SMAX1 overaccumulation suppresses rosette shoot branching and promotes leaf and petiole elongation.
Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. Electronic address: xinlisun@fafu.edu.cn.
ARABIDOPSIS: SMAX1/SMXL (SUPPRESSOR OF MAX2 1/SMAX1-LIKE) proteins function as transcriptional repressors in karrikin and strigolactone (SL) signaling pathways and regulate plant architecture. MAX2 is a common factor in the two signaling pathways and a component of the SCF complex that modulates the proteasome-mediated degradation of SMAX1/SMXLs. SMXL6, 7, and 8 proteins promote shoot branching and inhibit petiole elongation. Our study found that the accumulation of SMAX1 suppresses rosette shoot branching and increases cauline branches on the primary inflorescence stem, plant height, petiole length, and leaf length/width ratio. The SMAX1 accumulation enhances the expression of BRC1, HB53, HB40, and HB21 that modulate shoot branching. SMAX1 also regulates the expression of the genes involved in auxin transport, cytokinin signaling pathway, and SL biosynthesis. The expression analyses of these genes suggest that excessive SMAX1 should accelerate the transport of auxin and the biosynthesis of SL in plants. High SL concentration suppresses the bud development in smax1D mutant that accumulates SMAX1 protein in plant. However, the effects of cytokinin and auxin on shoot branching remain elusive in the mutant with excessive SMAX1. SMAX1 regulates leaf shape and petiole length via modulating TCP1 expression. Our findings reveal a novel function of SMAX1 and new mechanism of shoot branching.
PMID: 33756344
Gene , IF:2.984 , 2021 Mar , V774 : P145424 doi: 10.1016/j.gene.2021.145424
Relative expression of putative genes involved in galanthamine and other Amaryllidaceae alkaloids biosynthesis in Narcissus field and in vitro tissues.
Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom. Electronic address: aferdausi.gpb@bau.edu.bd.; Associate Pro-Vice Chancellor and Senior Lecturer, Crop Production Technology, Royal Agricultural University, Cirencester Gloucestershire, GL7 6JS, United Kingdom. Electronic address: Xianmin.Chang@rau.ac.uk.; Head of Plant Genomics, Anthony Hall Group, Earlham Institute, Norwich Research Park, Norwich NR4 7UG, United Kingdom. Electronic address: anthony.hall@earlham.ac.uk.; Honorary Senior Lecturer, Functional and Comparative Genomics, Institute of Integrative Biology, The Biosciences Building, Crown Street, The University of Liverpool, Liverpool L69 7ZB, United Kingdom. Electronic address: m.g.jones@liverpool.ac.uk.
The Narcissus pseudonarcissus cv. Carlton contains Amaryllidaceae alkaloids namely galanthamine, lycorine, homolycorine, narciclasine, which are noted for their pharmaceutical properties such as for the treatment of early to mid-stage Alzheimer's diseases, cancer, tumor etc. Alkaloid biosynthesis using plant in vitro systems has been considered as a tool for drug discovery and the pathways are starting to be understood but still far from complete. Therefore, the study was emphasized to observe the relative expressions of putative genes involved in the biosynthetic pathway leading to the Amaryllidaceae alkaloids in field grown bulbs and developing cell culture systems in Narcissus. MS media fortified with growth regulators were used for the development of tissue culture from Carlton twin-scale explants. MS medium with high auxin, 20 mg/l NAA was the best medium for callus growth and maintenance while media with low auxin, 4 mg/l NAA and MS basal media gave the maximum bulblets. Field tissues showed a higher amount of galanthamine content; i.e. basal plate (1050-1310 microg Gal/g FW) and bulb (980-1150 microg Gal/g FW) than the culture derived samples; callus (1.0-7.0 microg Gal/g FW) and bulblets (12-215 microg Gal/g FW) on a fresh weight (FW) basis. GC-MS chromatograms of samples under study also showed the presence of other important alkaloids i.e. lycorine, homolycorine, lycorenine, haemanthamine, crinamine, lycoramine and tazettine. RNA extracted from in vitro callus, bulblets and field grown bulb, basal plate were used for PCR to detect the relative expression of putative genes; P450, PAL, TYDC and NpO4OMT normalized to actin. The selected transcripts for P450s and TYDC were expressed in both field and in vitro tissues. Higher expressions of PAL were observed in calli than field samples. The expression of NpN4OMT was notably higher in field samples than in vitro tissues. Therefore, in vitro tissues could be a good source for the reproducible and easy extraction of alkaloids from plants.
PMID: 33434626
Gene , IF:2.984 , 2021 Mar , V772 : P145355 doi: 10.1016/j.gene.2020.145355
Transcriptome sequencing and differential gene expression analysis reveal the mechanisms involved in seed germination and protocorm development of Calanthe tsoongiana.
Research Institution of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, Zhejiang, China.; Research Institution of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, Zhejiang, China. Electronic address: tmin115@126.com.
Calanthe tsoongiana is a rare orchid species native to China. Asymbiotic seed germination is of great importance in the ex situ conservation of this species. Based on morphological characteristics and anatomical structures, the C. tsoongiana developmental process from seeds to seedlings was divided into four stages (SA, PB, PC and PD), and subsequently, changes in endogenous hormone contents and gene expression were assessed using RNA-seq analysis. K-means analysis divided the DEGs into eight clusters. The gene expression decreased markedly between the imbibed seed and globular protocorm stages, with this being the most notably enriched cluster. During the seed germination period, DEGs were dominated by ATP metabolic processes, respiration and photosynthesis. A small change in gene expression was found in the globular protocorm versus the finger-like protocorm stages. During the last developmental stage, DEGs were significantly enriched in lignin catabolic processes and plant-type secondary cell wall biogenesis. DEG homologs, such as TSA1, DAO, NCED1, STM, and CUC2, were related to phytohormones and the morphogenesis of shoots, leaves and roots. Particularly, interactions between CUC2 and STM as well as AS1 and STM were likely involved in protocorm formation and development. Furthermore, TSA1 and DAO were distinctly validated and implicated in the synthesis and metabolism of auxin, which has a pivotal role in plant development. Our study is the first to combine morphological and transcriptome analysis to examine the process of protocorm formation and development. The results provide a foundation for understanding the mechanisms of seed germination and protocorm development of C. tsoongiana.
PMID: 33340562
Gene , IF:2.984 , 2021 Mar , V772 : P145349 doi: 10.1016/j.gene.2020.145349
Genome-wide identification of polar auxin transporter gene families reveals a possible new polar auxin flow in inverted cuttings of Populus yunnanensis.
Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming 650224, China; Institute of Jiangxi Oil-tea Camellia, Jiujiang University, Jiujiang 332005, China. Electronic address: 6090078@jju.edu.cn.; Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming 650224, China; Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming 650224, China.; Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming 650224, China; Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming 650224, China; Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming 650224, China. Electronic address: hecz@swfu.edu.cn.
Inverted cuttings of Populus yunnanensis are characterized by enlarged stems and dwarfed new shoots, and phytohormones play a crucial role in the response to inversion. The polar auxin transport (PAT) system is distinct from the transport systems of other hormones and is controlled by three major transporter gene families: pin-formed (PIN), auxin-resistant/like aux (AUX/LAX) and ATP-binding cassette transporters of the B class (ABCB). Here, we identified these three families in P. trichocarpa, P. euphratica and P. yunnanensis through a genome-wide analysis. The Populus PIN, AUX/LAX and ABCB gene families comprised 15, 8 and 31 members, respectively. Most PAT genes in Populus and Arabidopsis were identified as clear sister pairs, and some had unique motifs. Transcriptome profiling revealed that the expression of most PAT genes was unrelated to cutting inversion and that only several genes showed altered expression when cuttings were inverted. The auxin content difference at positions was opposite in upright and inverted cutting bodies during rooting, which obeyed the original plant polarity. However, during plant growth, the two direction types exhibited similar auxin movements in the cutting bodies, and the opposite auxin changes were observed in new shoots. Four PAT genes with a positive response to cutting inversion, PyuPIN10, PyuPIN11, PyuLAX6 and PyuABCB27, showed diverse expression patterns between upright and inverted cuttings during rooting and plant growth. Furthermore, PAT gene expression retained its polarity, which differs from the results found for auxin flow during plant growth. The inconformity indicated that a new downward auxin flow in addition to the old upward flow might be established during the growth of inverted cuttings. Some highly polar PAT genes were involved in the maintenance of original auxin polarity, which might cause the enlarged stems of inverted cuttings. This work lays a foundation for understanding the roles of auxin transport in plant responses to inversion.
PMID: 33338511
Virus Res , IF:2.934 , 2021 Mar : P198400 doi: 10.1016/j.virusres.2021.198400
Differential miRNA profiles in South African cassava mosaic virus-infected cassava landraces reveal clues to susceptibility and tolerance to cassava mosaic disease.
School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa.; School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa. Electronic address: Chrissie.Rey@wits.ac.za.
Specific miRNA families are involved in susceptibility or antiviral immunity in plants. Manihot esculenta Crantz (cassava) is a perennial plant that is an important food security crop in sub-Saharan Africa. Cassava is susceptible to several begomoviruses that cause cassava mosaic disease (CMD). In this study, we investigated the leaf miRNAome response in a tolerant (TME3) and susceptible (T200) cassava landrace challenged with South African cassava mosaic virus. RNAseq was performed on leaf samples at 12, 32 and 67 days post infection (dpi), representing early, symptomatic and late persistent stages of CMD infection. Significantly, distinct profiles of conserved miRNA family expression between the T200 and TME3 landraces at the three infection stages were observed. Notably at 12 days post SACMV infection, TME3 exhibited significant downregulation (log2fold<2.0) of 42 %, compared to 9% in T200, of the conserved miRNA families. This demonstrates an overall early response to SACMV in TME3 prior to symptom appearance not observed in T200, and expression of a large cohort of miRNA-regulated genes. Notably, at early infection, downregulation of mes-miR162 and 168 that target antiviral posttransriptional gene silencing (PTGS) regulators DCL1 and AGO1, respectively, was observed in TME3, and AGO1 and DCL1 expression was higher compared to T200 post infection. Early rapid responses prior to symptom development, including RNA silencing, may be key to establishing the tolerance/recovery phenotype exhibited by TME3 landrace later on at 67 dpi. At recovery, TME3 was hallmarked by a highly significant down-regulation of mes-miR167. MiR167 targets an auxin responsive factor which plays a role in auxin signaling and adaptive responses to stress, suggesting the importance of the auxin signaling in recovery of SACMV-induced symptoms. The gene targets of these miRNAs and their associated networks may provide clues to the molecular basis of CMD tolerance in perennial hosts such as cassava.
PMID: 33753179
PLoS One , IF:2.74 , 2021 , V16 (3) : Pe0248274 doi: 10.1371/journal.pone.0248274
De novo genome assembly of Bacillus altitudinis 19RS3 and Bacillus altitudinis T5S-T4, two plant growth-promoting bacteria isolated from Ilex paraguariensis St. Hil. (yerba mate).
Laboratorio de Biotecnologia Molecular, Instituto de Biotecnologia Misiones "Dra. Maria Ebe Reca" (InBioMis), CONICET, Facultad de Ciencias Exactas, Quimicas y Naturales/FCEQyN, Universidad Nacional de Misiones/UNaM, Posadas, Misiones, Argentina.; Catedra de Bacteriologia, Dpto. de Microbiologia, Facultad de Ciencias Exactas, Quimicas y Naturales/FCEQyN, Universidad Nacional de Misiones/UNaM, Posadas, Misiones, Argentina.
Plant growth-promoting bacteria (PGPB) are a heterogeneous group of bacteria that can exert beneficial effects on plant growth directly or indirectly by different mechanisms. PGPB-based inoculant formulation has been used to replace chemical fertilizers and pesticides. In our previous studies, two endophytic endospore-forming bacteria identified as Bacillus altitudinis were isolated from roots of Ilex paraguariensis St. Hil. seedlings and selected for their plant growth-promoting (PGP) properties shown in vitro and in vivo. The purposes of this work were to assemble the genomes of B. altitudinis 19RS3 and T5S-T4, using different assemblers available for Windows and Linux and to select the best assembly for each strain. Both genomes were also automatically annotated to detect PGP genes and compare sequences with other genomes reported. Library construction and draft genome sequencing were performed by Macrogen services. Raw reads were filtered using the Trimmomatic tool. Genomes were assembled using SPAdes, ABySS, Velvet, and SOAPdenovo2 assemblers for Linux, and Geneious and CLC Genomics Workbench assemblers for Windows. Assembly evaluation was done by the QUAST tool. The parameters evaluated were the number of contigs >/= 500 bp and >/= 1000 bp, the length of the longest contig, and the N50 value. For genome annotation PROKKA, RAST, and KAAS tools were used. The best assembly for both genomes was obtained using Velvet. The B. altitudinis 19RS3 genome was assembled into 15 contigs with an N50 value of 1,943,801 bp. The B. altitudinis T5S-T4 genome was assembled into 24 contigs with an N50 of 344,151 bp. Both genomes comprise several genes related to PGP mechanisms, such as those for nitrogen fixation, iron metabolism, phosphate metabolism, and auxin biosynthesis. The results obtained offer the basis for a better understanding of B. altitudinis 19RS3 and T5S-T4 and make them promissory for bioinoculant development.
PMID: 33705487
Funct Plant Biol , IF:2.617 , 2021 Mar doi: 10.1071/FP20319
Expression of key auxin biosynthesis genes correlates with auxin and starch content of developing wheat (Triticum aestivum) grains.
The effect of auxin on wheat (Triticum aestivum L.) grain size is contentious. Additionally, the contributions to the IAA pool from de novo synthesis versus hydrolysis of IAA-glucose are unclear. Here, we describe the first comprehensive study of tryptophan aminotransferase and indole-3-pyruvate mono-oxygenase expression from 5 to 20 days after anthesis. A comparison of expression data with measurements of endogenous IAA via combined liquid chromatography-tandem mass spectrometry using heavy isotope labelled internal standards indicates that TaTAR2-B3, TaYUC9-A1, TaYUC9-B, TaYUC9-D1, TaYUC10-A and TaYUC10-D are primarily responsible for IAA production in developing grains. Furthermore, these genes are expressed specifically in developing grains, like those found in rice (Oryza sativa L.) and maize (Zea mays L.). Our results cast doubt on the proposed role of THOUSAND-GRAIN WEIGHT gene, TaTGW6, in promoting larger grain size via negative effects on grain IAA content. Work on this gene overlooked the contribution of IAA biosynthesis from tryptophan. Although IAA synthesis occurs primarily in the endosperm, we show the TaYUC9-1 group is also strongly expressed in the embryo. Within the endosperm, TaYUC9-1 expression is highest in aleurone and transfer cells, suggesting that IAA has a key role in differentiation of these tissues as has been proposed for other cereals.
PMID: 33715766
Funct Plant Biol , IF:2.617 , 2021 Mar doi: 10.1071/FP20381
Advances in the role of auxin for transcriptional regulation of lignin biosynthesis.
Lignin is a natural polymer interlaced with cellulose and hemicellulose in secondary cell walls (SCWs). Auxin acts via its signalling transduction to regulate most of plant physiological processes. Lignification responds to auxin signals likewise and affects the development of anther and secondary xylem in plants. In this review, the research advances of AUXIN RESPONSE FACTOR (ARF)-dependent signalling pathways regulating lignin formation are discussed in detail. In an effort to facilitate the understanding of several key regulators in this process, we present a regulatory framework that comprises protein-protein interactions at the top and protein-gene regulation divided into five tiers. This characterises the regulatory roles of auxin in lignin biosynthesis and links auxin signalling transduction to transcriptional cascade of lignin biosynthesis. Our works further point to several of significant problems that need to be resolved in the future to gain a better understanding of the underlying mechanisms through which auxin regulates lignin biosynthesis.
PMID: 33663680
J Sci Food Agric , IF:2.614 , 2021 Mar , V101 (5) : P2027-2041 doi: 10.1002/jsfa.10822
Seed priming and foliar application with jasmonic acid enhance salinity stress tolerance of soybean (Glycine max L.) seedlings.
Salt-Soil Agricultural Center, Institute of Agriculture Resources and Environment, Jiangsu Academy of Agricultural Sciences (JAAS), Nanjing, China.; Department of Agronomy, Faculty of Agriculture, Mansoura University, Mansoura, Egypt.; College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, China.; Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Yancheng Teachers University, Yancheng, China.; Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, People's Republic of China.; State Key Laboratory of Silviculture, Zhejiang A&F University, Hangzhou, China.; College of Chemical Engineering, Nanjing Forestry University, Nanjing, China.; College of Agricultural Science and Engineering, Hohai University, Nanjing, China.; Botany Department, Faculty of Science, Tanta University, Tanta, Egypt.; Seed Science Center, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
BACKGROUND: Jasmonic acid (JA) is an important molecule that has a regulatory effect on many physiological processes in plant growth and development under abiotic stress. This study investigated the effect of 60 mumol L(-1) of JA in seed priming (P) at 15 degrees C in darkness for 24 h, foliar application (F), and/or their combination effect (P + F) on two soybean cultivars - 'Nannong 99-6' (salt tolerant) and 'Lee 68' (salt sensitive) - under salinity stress (100 mmol L(-1) sodium chloride (NaCl)). RESULTS: Salinity stress reduced seedling growth and biomass compared with that in the control condition. Priming and foliar application with JA and/or their combination significantly improved water potential, osmotic potential, water use efficiency, and relative water content of both cultivars under salinity stress. Similarly, seed priming with JA, foliar application of JA, and/or their combination significantly improved the following properties under salinity stress compared with the untreated seedlings: net photosynthetic rate by 68.03%, 59.85%, and 76.67% respectively; transpiration rate by 74.85%, 55.10%, and 80.26% respectively; stomatal conductance by 69.88%, 78.25%, and 26.24% respectively; intercellular carbon dioxide concentration by 61.64%, 40.06%, and 65.79% respectively; and total chlorophyll content by 47.41%, 41.02%, and 55.73% respectively. Soybean plants primed, sprayed with JA, or treated with their combination enhanced the chlorophyll fluorescence, which was damaged by salinity stress. JA treatments improved abscisic acid, gibberellic acid, and JA levels by 60.57%, 62.50% and 52.25% respectively under salt stress compared with those in the control condition. The transcriptional levels of the FeSOD, POD, CAT, and APX genes increased significantly in the NaCl-stressed seedlings irrespective of JA treatments. Moreover, JA treatment resulted in a reduction of sodium ion concentration and an increase of potassium ion concentrations in the leaf and root of both cultivars regardless of salinity stress. Monodehydroascorbate reductase, dehydroascorbate reductase, and proline contents decreased in the seedlings treated with JA under salinity stress, whereas the ascorbate content increased with JA treatment combined with NaCl stress. CONCLUSION: The application of 60 mumol L(-1) JA improved plant growth by regulating the interaction between plant hormones and hydrogen peroxide, which may be involved in auxin signaling and stomatal closure under salt stress. These methods could efficiently protect early seedlings and alleviate salt stress damage and provide possibilities for use in improving soybean growth and inducing tolerance against excessive soil salinity. (c) 2020 Society of Chemical Industry.
PMID: 32949013
J Plant Res , IF:2.185 , 2021 Mar doi: 10.1007/s10265-021-01280-w
Overexpression of KcNHX1 gene confers tolerance to multiple abiotic stresses in Arabidopsis thaliana.
Xinjiang Production and Construction Crops Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, Tarim University, Alaer, 843300, Xinjiang, China. wyqwxf@126.com.; College of Life Sciences, Tarim University, Alaer, 843300, Xinjiang, China. wyqwxf@126.com.; College of Life Sciences, Tarim University, Alaer, 843300, Xinjiang, China.; Xinjiang Production and Construction Crops Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, Tarim University, Alaer, 843300, Xinjiang, China.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
Abiotic stresses such as drought, salinity, and heat affect plant growth and development. Karelinia caspica is a unique perennial herb that grows in desert area for a long time and has strong tolerance to environmental stresses. In order to explore the functions of the Na(+)/H(+) antiporter gene from eremophyte K. caspica (KcNHX1) in the abiotic stress response of K. caspica and the underlying regulatory mechanisms, we constructed a vector overexpressing KcNHX1 and transformed it into Arabidopsis thaliana. The physiological results showed that the overexpression of KcNHX1 in A. thaliana not only enhanced the plant's tolerance to salt stress, but also enhanced its tolerance to drought and heat stress at the seedling stage. In addition, KcNHX1-overexpressing plants exhibited enhanced reproductive growth under high temperature, which was mediated by increased auxin accumulation. Taken together, our results indicate that KcNHX1 from an eremophyte can be used as a candidate gene to improve multiple stress tolerance in other plants.
PMID: 33723703
Plant Biol (Stuttg) , IF:2.167 , 2021 Mar doi: 10.1111/plb.13253
Characterizing the impact of high temperature during the grain filling on phytohormone levels, enzyme activities and metabolic profiles of the early indica-rice variety.
Soil and Fertilizer & Resources and Environment Institute, Jiangxi Academy of Agricultural Sciences, Nanchang, 330200.; Ganzhou Institute of Agricultural Sciences, Ganzhou, 341000.; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Global warming results in high temperature stress (HTS), which presents severe challenges for the worldwide modern agricultural production and will have significant impacts on the yield and quality of crops. Accumulation of photosynthetic products, activities of the sucrose-starch metabolism related enzymes, phytohormone levels and metabolic profiling using LC-MS were analysed in the flag leaves and/or the in the developing grains treated with HTS during the grain filling stage of an indica-rice. HTS induced significant yield loss, and caused grain quality reduction with less amylose contents. HTS reduced photosynthetic product accumulation in flag leaves and less starch accumulation in the developing grains, compared to that under normal temperatures. The activities of sucrose-starch metabolism related enzymes were dis-regulated in developing grains grown under HT. Moreover, phytohormone homeostasis in the flag leaves and developing grains was also dramatically disturbed by HT. Metabolic profiling detected many metabolites had remarkably different relative fold abundances at different timepoints in the developing grains under HT versus those under normal temperatures, these metabolites enriched in different HTS-responding pathways. The changed phytohormone ratio and auxin levels might associate with the reduced photosynthetic product and its translocation, and ultimately reduced starch accumulation in the developing grains. The detected metabolites might play different roles in responding to the influence of HTS in developing grains at different development stages. These results provide theoretical reference and the basis for regulation of rice production with higher quality and yields when grown under HT.
PMID: 33721388
Plant Biol (Stuttg) , IF:2.167 , 2021 Mar doi: 10.1111/plb.13252
ABA crosstalk with auxin and ethylene in biosynthesis and degradation of inulin-type fructans.
Division of Biotechnology, Agronomy and Plant Breeding Dept, Agricultural and Natural Resources College, University of Tehran, Karaj, Iran.; Evidence-based Phytotherapy & Complementary Medicine Research Center, Alborz University of Medical Sciences, Karaj, Iran.; Department of Pharmacognosy, School of Pharmacy, Alborz University of Medical Sciences, Karaj, Iran.; University of Perugia, Department of Agricultural, Food and Environmental Science, via San Costanzo s.n.c, 06126, Perugia, Italy.
The effect of different hormones on fructan accumulation and the regulation of biosynthesis and degradation genes has been confirmed; however, information of hormonal interaction mechanisms on fructan content and mean degree of polymerization (mDP) is limited. Cell suspension cultures of chicory were prepared and treated using abscisic acid (ABA), auxin (AUX), Ethylene (ETH), ABA+AUX, and ABA+ETH, then inulin concentration, mDP of inulin and expression of FAZY genes were determined. Low concentration of AUX and ETH increased fructan content and high concentration of AUX and ETH decreased it. Exogenous ABA increased mDP of inulin and it coincided with the low expression of 1-FEHII. In hormonal interaction, ABA changed and adjusted the effect of both AUX and ETH. ABA with a low level of both hormones resulted in a decrease in inulin content and increasing mDP and it coincided with low expression of FEHII. ABA with a high level of both hormones caused increasing in inulin content with lower mDP and it coincided with high expression of biosynthesis (1-FFT) and degradation (1-FEHII) genes. The effect of both AUX and ETH was almost the same although the effect of ETH was more severe. ABA had a modular role in both combinations with AUX and ETH. Among biosynthesis and degradation genes, the expression of 1-FEHII was more affected by hormones.
PMID: 33710751
Biol Open , IF:2.029 , 2021 Mar , V10 (3) doi: 10.1242/bio.052142
Root system architecture analysis in Mesembryanthemum crystallinum (ice plant) seedlings reveals characteristic root halotropic response.
Faculty of Agriculture, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, Aichi 464-8601, Japan.; Faculty of Agriculture, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, Aichi 464-8601, Japan thiro@meijo-u.ac.jp.
One of the major environmental stress factors that affect root growth is salinity. Arabidopsis thaliana, a glycophyte, shows halotropism, whereby it alters the direction of root growth in a non-gravitropic pattern to evade high soil salinity. Asymmetric auxin distribution regulated by the relocation of auxin-efflux carrier proteins is a key cellular event in the halotropic response. However, there are no reports of halotropism in halophytes. Here, we investigated root growth traits in Mesembryanthemum crystallinu m (ice plant), under high salinity conditions. We hypothesized that ice plant roots would show halotropic responses different from those of Arabidopsis Notably, similar to halotropism observed in Arabidopsis, ice plant roots showed continuous root bending under salinity stress. However, the root elongation rate did not change in ice plants. Expression analyses of several genes revealed that auxin transport might be partially involved in ice plant halotropism. This study enhances our understanding of halophyte root adaptation to high salinity stress.
PMID: 32816696
J Mol Evol , IF:1.821 , 2021 Mar doi: 10.1007/s00239-021-10005-5
Molecular Evolution and Local Root Heterogeneous Expression of the Chenopodium quinoa ARF Genes Provide Insights into the Adaptive Domestication of Crops in Complex Environments.
College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.; State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Key Laboratory of Major Crop Diseases and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China.; Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture Rural Affairs, School of Pharmacy and Bioengineering, Chengdu University, Chengdu, 610106, China.; College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China. chenhui@sicau.edu.cn.
Auxin response factors (ARFs) influence plant growth and development via the coupling of basic biological processes. However, the evolution, expansion, and regulatory mechanisms of ARFs in the domesticated crop quinoa after artificial selection remain elusive. In this study, we systematically identified 30 Chenopodium quinoa ARFs (CqARFs). In this typical domesticated crop, ARFs divided into three subfamilies are subjected to strong purification selection and have a highly conserved evolutionary pattern. Polyploidy is the primary reason for the expansion of the ARF family after quinoa domestication. The expression patterns of CqARFs in different tissues have been differentiated, and CqARF2, 5, 9 and 10 from class A have the characteristics of local heterogeneous expression in different regions of roots, which may be the key factors for crops to respond in complex environments. Overall, we examined the evolution and expansion of ARFs in representative domesticated crops using the genome, transcriptome, and molecular biology and discovered a class A ARF-centered heterogeneous expression network that played an important role in auxin signaling and environmental responses. We provide new insights into how ARFs promote domesticated crop adaptation to artificial selection by polyploid expansion.
PMID: 33755734
Curr Microbiol , IF:1.746 , 2021 Mar doi: 10.1007/s00284-021-02453-5
Biostimulation of Vigna unguiculata subsp. sesquipedalis-Cultivar Sesquipedalis (Yardlong Bean)-by Brevibacillus sp. B65 in Organoponic Conditions.
Centro de Estudios de Biotecnologia Industrial, Facultad de Ciencias Naturales y Exactas, Universidad de Oriente, Ave. Patricio Lumumba S/N, PO Box 90500, Santiago de Cuba, Cuba. torbera@gmail.com.; Centro de Estudios de Biotecnologia Industrial, Facultad de Ciencias Naturales y Exactas, Universidad de Oriente, Ave. Patricio Lumumba S/N, PO Box 90500, Santiago de Cuba, Cuba.; Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590, Diepenbeek, Belgium.
In the current research, the effects of fluid inoculum of Brevibacillus sp. B65, a plant growth promoting microorganism (PGPM), on growth of V. unguiculata subsp. sesquipedalis cultivated in organoponic conditions were evaluated in comparison with traditional inorganic and organic fertilizers. Plant growth promotion of Yardlong bean was assessed through the effects of four different treatments on plant growth and development traits, as well as on crop yield. The four treatments were NPK-inorganic fertilizer (T1), organic matter alone (T2), fluid inoculum of B65 alone (T3) and inoculum supplemented with organic matter (T4). The inoculum of B65 supplemented with organic matter improved different traits of plant growth and development such as seed germination, root development, plant and leaves growth, flowering, as well as crop yield. The main impact of the inoculation mixture was on seed emergence. In the present research, it was demonstrated that biostimulation of Vigna unguiculata subsp. sesquipedalis through inoculation of PGPM Brevibacillus sp. B65 supplemented with organic matter, may replace traditional organic and inorganic fertilization strategies. The nature of the positive influence of strain B65 on the legume is not well understood yet; however, it could be attributed to bacterial phytostimulation through auxin and ethylene production, as well as P mobilization. Additionally, organic matter supplementation demonstrated a stimulating effect on B65 traits. This is of utmost importance and will have a main impact on the sustainable development of agronomical practices.
PMID: 33770214
Plant Signal Behav , IF:1.671 , 2021 Mar , V16 (3) : P1860386 doi: 10.1080/15592324.2020.1860386
The TARANI/ UBIQUITIN PROTEASE 14 protein is required for lateral root development in Arabidopsis.
Department of Microbiology and Cell Biology, Indian Institute of Science , Bengaluru, India.
In our article published in Plant Physiology, we had reported tarani (tni) mutant in Arabidopsis, in which poly-ubiquitin hydrolysis is adversely affected, shows pleiotropic phenotypic defects including fewer lateral roots due to the stabilization of several AUX/IAAs and reduced auxin response. TNI encodes UBIQUITIN-SPECIFIC PROTEASE14 that maintains normal auxin response through ubiquitin recycling. Fewer lateral roots observed in tni could be due to defects in their primordia initiation or subsequent elongation post-initiation. Here we have tested this by marking the lateral root primordia with pCycB1;1::CycB1;1(DB):GUS reporter and counting the number of lateral root at various stages development of as a marker of lateral root primordium. The results suggest that TNI/UBP14 is required for LRP development, and a reduction in TNI activity causes a delay in LRP initiation and consequently shorter lateral roots in the tni seedlings. ABBREVIATIONS: LRP, lateral root primordium; XPP, xylem pole pericycle; LRFC, lateral root founder cells.
PMID: 33380274
J Genet Eng Biotechnol , 2021 Mar , V19 (1) : P40 doi: 10.1186/s43141-021-00140-3
In vitro propagation and cytological analysis of Sophora mollis Royle: an endangered medicinal shrub.
Botanical Survey of India, Northern Regional Centre, Dehradun, Uttarakhand, 248195, India.; Botanical Survey of India, Eastern Regional Centre, Shillong, Meghalaya, 793003, India.; Botanical Survey of India, Northern Regional Centre, Dehradun, Uttarakhand, 248195, India. panwar_giriraj@rediffmail.com.; Botanical Survey of India, Kolkata, West Bengal, India.
BACKGROUND: Sophora mollis Royle (family Fabaceae, subfamily-Papilionaceae) is a multipurpose legume distributed in plains and foothills of the North-West Himalaya to Nepal and is facing high risk of extinction due to habitat loss and exploitation by the local people for its fuel and fodder values. Therefore, the present study was conducted to standardize a micropropagation protocol for Sophora mollis by using shoot tip explants and to study the meiotic chromosome count in the species. RESULTS: Multiple shoots were induced in shoot tip explants of Sophora mollis in Murashige and Skoog medium supplemented with different concentrations of cytokinins alone (BAP, TDZ, and Kinetin) and in combination with varying concentrations of NAA. MS medium supplemented with BAP (8.9 muM) was observed to be the optimal medium for multiple shoot induction and maximum 25.32 shoots per explant was obtained with average length of 4.5 +/- 0.8 cm. In vitro developed shoots were transferred onto rooting media supplemented with different concentrations of auxin (IAA, IBA, and NAA). Maximum 86% rooting was observed in half-strength MS medium supplemented with 21.20 muM NAA with an average of 21.26 roots per culture. In vitro raised plantlets were adapted to greenhouse for better acclimatization and 60% plants were successfully transferred to the open environment. Based on the chromosome counts available from the literature and the current study, the species tend to show a basic chromosome number of x = 9. CONCLUSION: The micropropagation protocol standardized can be helpful for the ex situ mass multiplication and germplasm conservation of the endangered species. Moreover, the ex situ conservation approach will be helpful in actively bridging the gap between ex situ and in situ approaches through the reintroduction of species in the wild. The cytological studies revealed the basic chromosome number x = 9 of the species.
PMID: 33721154