Nat Plants , IF:13.256 , 2020 Aug doi: 10.1038/s41477-020-0739-7
Genetic dissection of the auxin response network.
The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot, Israel.; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. jreed@email.unc.edu.; Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. jreed@email.unc.edu.; The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot, Israel. naomi.ori@mail.huji.ac.il.
The expansion of gene families during evolution, which can generate functional overlap or specialization among their members, is a characteristic feature of signalling pathways in complex organisms. For example, families of transcriptional activators and repressors mediate responses to the plant hormone auxin. Although these regulators were identified more than 20 years ago, their overlapping functions and compensating negative feedbacks have hampered their functional analyses. Studies using loss-of-function approaches in basal land plants and gain-of-function approaches in angiosperms have in part overcome these issues but have still left an incomplete understanding. Here, we propose that renewed emphasis on genetic analysis of multiple mutants and species will shed light on the role of gene families in auxin response. Combining loss-of-function mutations in auxin-response activators and repressors can unravel complex outputs enabled by expanded gene families, such as fine-tuned developmental outcomes and robustness. Similar approaches and concepts may help to analyse other regulatory pathways whose components are also encoded by large gene families.
PMID: 32807951
Nat Plants , IF:13.256 , 2020 Aug , V6 (8) : P1020-1030 doi: 10.1038/s41477-020-0737-9
Local auxin biosynthesis is required for root regeneration after wounding.
Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel.; Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.; Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.; California Institute of Technology, Pasadena, CA, USA.; Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel. idan.efroni@mail.huji.ac.il.
The root meristem can regenerate following removal of its stem-cell niche by recruitment of remnant cells from the stump. Regeneration is initiated by rapid accumulation of auxin near the injury site but the source of this auxin is unknown. Here, we show that auxin accumulation arises from the activity of multiple auxin biosynthetic sources that are newly specified near the cut site and that their continuous activity is required for the regeneration process. Auxin synthesis is highly localized while PIN-mediated transport is dispensable for auxin accumulation and tip regeneration. Roots lacking the activity of the regeneration competence factor ERF115, or that are dissected at a zone of low regeneration potential, fail to activate local auxin sources. Remarkably, restoring auxin supply is sufficient to confer regeneration capacity to these recalcitrant tissues. We suggest that regeneration competence relies on the ability to specify new local auxin sources in a precise temporal pattern.
PMID: 32747761
Nat Commun , IF:12.121 , 2020 Aug , V11 (1) : P3914 doi: 10.1038/s41467-020-17602-w
Auxin-induced signaling protein nanoclustering contributes to cell polarity formation.
FAFU-UCR Joint Center for Horticultural Biology and Metabolomics Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.; Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA.; Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, 10010 N Torrey Pines Road, La Jolla, CA, 92037, USA.; Department of Mathematics, University of California, Riverside, CA, 92521, USA.; Department of Mathematics, University of California, Riverside, CA, 92521, USA. weitaoc@ucr.edu.; Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA. yang@ucr.edu.
Cell polarity is fundamental to the development of both eukaryotes and prokaryotes, yet the mechanisms behind its formation are not well understood. Here we found that, phytohormone auxin-induced, sterol-dependent nanoclustering of cell surface transmembrane receptor kinase 1 (TMK1) is critical for the formation of polarized domains at the plasma membrane (PM) during the morphogenesis of cotyledon pavement cells (PC) in Arabidopsis. Auxin-induced TMK1 nanoclustering stabilizes flotillin1-associated ordered nanodomains, which in turn promote the nanoclustering of ROP6 GTPase that acts downstream of TMK1 to regulate cortical microtubule organization. In turn, cortical microtubules further stabilize TMK1- and flotillin1-containing nanoclusters at the PM. Hence, we propose a new paradigm for polarity formation: A diffusive signal triggers cell polarization by promoting cell surface receptor-mediated nanoclustering of signaling components and cytoskeleton-mediated positive feedback that reinforces these nanodomains into polarized domains.
PMID: 32764676
Plant Cell , IF:9.618 , 2020 Aug doi: 10.1105/tpc.19.00695
Auxin Regulates Sucrose Transport to Repress Petal Abscission in Rose (Rosa hybrida).
China Agricultural University CITY: Beijing China [CN].; Cornell University CITY: Ithaca STATE: New York POSTAL_CODE: 14853 United States Of America [US].; USDA ARS/UC Davis CITY: Davis STATE: CA POSTAL_CODE: 95616 United States Of America [US].; China Agricultural University CITY: Beijing China [CN] mac@cau.edu.cn.; China Agricultural University CITY: Beijing POSTAL_CODE: 100194 China [CN].
Developmental transitions in plants require adequate carbon resources, and organ abscission often occurs due to competition for carbohydrates/assimilates. Physiological studies have indicated that organ abscission may be activated by sucrose deprivation; however, an underlying regulatory mechanism that links sucrose transport to organ shedding has yet to be identified. Here, we report that transport of sucrose and the phytohormone auxin to petals through the phloem of the abscission zone (AZ) decreases during petal abscission in rose (Rosa hybrida), and that auxin regulates sucrose transport into the petals. Expression of the sucrose transporter RhSUC2 decreased in the AZ during rose petal abscission. Similarly, silencing of RhSUC2 reduced the sucrose content in the petals and promotes petal abscission. We established that the auxin signaling protein RhARF7 binds to the promoter of RhSUC2, and that silencing of RhARF7 reduces petal sucrose contents and promotes petal abscission. Overexpression of RhSUC2 in the petal AZ restored accelerated petal abscission caused by RhARF7 silencing. Moreover, treatment of rose petals with auxin and sucrose delayed ethylene-induced abscission, while silencing of RhARF7 and RhSUC2 accelerated ethylene-induced petal abscission. Our results demonstrate that auxin modulates sucrose transport during petal abscission, and that this process is regulated by a RhARF7-RhSUC2 module in the AZ.
PMID: 32843436
Curr Biol , IF:9.601 , 2020 Aug doi: 10.1016/j.cub.2020.07.055
HEARTBREAK Controls Post-translational Modification of INDEHISCENT to Regulate Fruit Morphology in Capsella.
Crop Genetics Department, John Innes Centre, Norwich NR4 7UH, UK.; Cell and Developmental Biology Department, John Innes Centre, Norwich NR4 7UH, UK.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umea, Sweden.; Department of Ecology, Environment and Plant Sciences, Science for Life Laboratory, Stockholm University, 106 91 Stockholm, Sweden.; Department of Biosciences, University of Durham, Durham DH1 3LE, UK.; Crop Genetics Department, John Innes Centre, Norwich NR4 7UH, UK. Electronic address: lars.ostergaard@jic.ac.uk.
Morphological variation is the basis of natural diversity and adaptation. For example, angiosperms (flowering plants) evolved during the Cretaceous period more than 100 mya and quickly colonized terrestrial habitats [1]. A major reason for their astonishing success was the formation of fruits, which exist in a myriad of different shapes and sizes [2]. Evolution of organ shape is fueled by variation in expression patterns of regulatory genes causing changes in anisotropic cell expansion and division patterns [3-5]. However, the molecular mechanisms that alter the polarity of growth to generate novel shapes are largely unknown. The heart-shaped fruits produced by members of the Capsella genus comprise an anatomical novelty, making it particularly well suited for studies on morphological diversification [6-8]. Here, we show that post-translational modification of regulatory proteins provides a critical step in organ-shape formation. Our data reveal that the SUMO protease, HEARTBREAK (HTB), from Capsella rubella controls the activity of the key regulator of fruit development, INDEHISCENT (CrIND in C. rubella), via de-SUMOylation. This post-translational modification initiates a transduction pathway required to ensure precisely localized auxin biosynthesis, thereby facilitating anisotropic cell expansion to ultimately form the heart-shaped Capsella fruit. Therefore, although variation in the expression of key regulatory genes is known to be a primary driver in morphological evolution, our work demonstrates how other processes-such as post-translational modification of one such regulator-affects organ morphology.
PMID: 32795439
Proc Natl Acad Sci U S A , IF:9.412 , 2020 Aug doi: 10.1073/pnas.2003733117
mRNA adenosine methylase (MTA) deposits m(6)A on pri-miRNAs to modulate miRNA biogenesis in Arabidopsis thaliana.
Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznan, Poland.; Centre For Modern Interdisciplinary Technologies, Nicolaus Copernicus University, 87-100 Torun, Poland.; School of Biosciences, Plant Science Division, University of Nottingham, Sutton Bonington, Loughborough LE12 5RD, United Kingdom.; Department of Biology, University of Pennsylvania, Philadelphia, PA 19104.; Department of Cellular and Molecular Biology, Nicolaus Copernicus University, 87-100 Torun, Poland.; Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznan, Poland; artjarmo@amu.edu.pl zofszwey@amu.edu.pl.
In Arabidopsis thaliana, the METTL3 homolog, mRNA adenosine methylase (MTA) introduces N (6)-methyladenosine (m(6)A) into various coding and noncoding RNAs of the plant transcriptome. Here, we show that an MTA-deficient mutant (mta) has decreased levels of microRNAs (miRNAs) but accumulates primary miRNA transcripts (pri-miRNAs). Moreover, pri-miRNAs are methylated by MTA, and RNA structure probing analysis reveals a decrease in secondary structure within stem-loop regions of these transcripts in mta mutant plants. We demonstrate interaction between MTA and both RNA Polymerase II and TOUGH (TGH), a plant protein needed for early steps of miRNA biogenesis. Both MTA and TGH are necessary for efficient colocalization of the Microprocessor components Dicer-like 1 (DCL1) and Hyponastic Leaves 1 (HYL1) with RNA Polymerase II. We propose that secondary structure of miRNA precursors induced by their MTA-dependent m(6)A methylation status, together with direct interactions between MTA and TGH, influence the recruitment of Microprocessor to plant pri-miRNAs. Therefore, the lack of MTA in mta mutant plants disturbs pri-miRNA processing and leads to the decrease in miRNA accumulation. Furthermore, our findings reveal that reduced miR393b levels likely contributes to the impaired auxin response phenotypes of mta mutant plants.
PMID: 32817553
Proc Natl Acad Sci U S A , IF:9.412 , 2020 Aug doi: 10.1073/pnas.2005911117
Root angle modifications by the DRO1 homolog improve rice yields in saline paddy fields.
Institute of Crop Science, National Agriculture and Food Research Organization (NARO), 305-8518 Tsukuba, Ibaraki, Japan.; Graduate School of Life Sciences, Tohoku University, 980-8577 Sendai, Miyagi, Japan.; Institute of Agrobiological Sciences, NARO, 305-8634 Tsukuba, Ibaraki, Japan.; PRESTO, Japan Science and Technology Agency (JST), 332-0012 Kawaguchi, Saitama, Japan.; Advanced Analysis Center, NARO, 305-8517 Tsukuba, Ibaraki, Japan.; Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 305-8566 Tsukuba, Ibaraki, Japan.; Graduate School of Agricultural Science, Tohoku University, 980-8572 Sendai, Miyagi, Japan.; Graduate School of Agricultural Science, Tohoku University, 980-8572 Sendai, Miyagi, Japan yuga@affrc.go.jp tadashi.sato.d1@tohoku.ac.jp.; Institute of Crop Science, National Agriculture and Food Research Organization (NARO), 305-8518 Tsukuba, Ibaraki, Japan; yuga@affrc.go.jp tadashi.sato.d1@tohoku.ac.jp.
The root system architecture (RSA) of crops can affect their production, particularly in abiotic stress conditions, such as with drought, waterlogging, and salinity. Salinity is a growing problem worldwide that negatively impacts on crop productivity, and it is believed that yields could be improved if RSAs that enabled plants to avoid saline conditions were identified. Here, we have demonstrated, through the cloning and characterization of qSOR1 (quantitative trait locus for SOIL SURFACE ROOTING 1), that a shallower root growth angle (RGA) could enhance rice yields in saline paddies. qSOR1 is negatively regulated by auxin, predominantly expressed in root columella cells, and involved in the gravitropic responses of roots. qSOR1 was found to be a homolog of DRO1 (DEEPER ROOTING 1), which is known to control RGA. CRISPR-Cas9 assays revealed that other DRO1 homologs were also involved in RGA. Introgression lines with combinations of gain-of-function and loss-of-function alleles in qSOR1 and DRO1 demonstrated four different RSAs (ultra-shallow, shallow, intermediate, and deep rooting), suggesting that natural alleles of the DRO1 homologs could be utilized to control RSA variations in rice. In saline paddies, near-isogenic lines carrying the qSOR1 loss-of-function allele had soil-surface roots (SOR) that enabled rice to avoid the reducing stresses of saline soils, resulting in increased yields compared to the parental cultivars without SOR. Our findings suggest that DRO1 homologs are valuable targets for RSA breeding and could lead to improved rice production in environments characterized by abiotic stress.
PMID: 32817523
Proc Natl Acad Sci U S A , IF:9.412 , 2020 Aug , V117 (34) : P20943-20949 doi: 10.1073/pnas.2006387117
From one cell to many: Morphogenetic field of lateral root founder cells in Arabidopsis thaliana is built by gradual recruitment.
Departamento de Biologia Molecular de Plantas, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico (UNAM), Cuernavaca 62250, Mexico.; Laboratorio de Analisis de Imagenes y Vision por Computadora, Instituto de Biotecnologia, UNAM, Cuernavaca 62250, Mexico.; Departamento de Biologia Molecular de Plantas, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico (UNAM), Cuernavaca 62250, Mexico; jdubrov@ibt.unam.mx.
The reiterative process of lateral root (LR) formation is widespread and underlies root system formation. However, early LR primordium (LRP) morphogenesis is not fully understood. In this study, we conducted both a clonal analysis and time-lapse experiments to decipher the pattern and sequence of pericycle founder cell (FC) participation in LR formation. Most commonly, LRP initiation starts with the specification of just one FC longitudinally. Clonal and anatomical analyses suggested that a single FC gradually recruits neighboring pericycle cells to become FCs. This conclusion was validated by long-term time-lapse live-imaging experiments. Once the first FC starts to divide, its immediate neighbors, both lengthwise and laterally, are recruited within the hour, after which they recruit their neighboring cells within a few hours. Therefore, LRP initiation is a gradual, multistep process. FC recruitment is auxin-dependent and is abolished by treatment with a polar auxin transport inhibitor. Furthermore, FC recruitment establishes a morphogenetic field where laterally peripheral cells have a lower auxin response, which is associated with a lower proliferation potential, compared to centrally located FCs. The lateral boundaries of the morphogenetic field are determined by phloem-adjacent pericycle cells, which are the last cells to be recruited as FCs. The proliferation potential of these cells is limited, but their recruitment is essential for root system formation, resulting in the formation of a new vascular connection between the nascent and parent root, which is crucial for establishing a continuous and efficient vascular system.
PMID: 32817465
New Phytol , IF:8.512 , 2020 Aug doi: 10.1111/nph.16887
Cellular requirements for PIN polar cargo clustering in Arabidopsis thaliana.
Institute of Science and Technology Austria (IST Austria), 3400, Klosterneuburg, Austria.; Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Gent, Belgium.; Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Loughborough, LE12 5RD, UK.; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences (BOKU), 1190, Vienna, Austria.; Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan.; Ghent University, Department of Plant Biotechnology and Bioinformatics, 9052 Ghent, Belgium and VIB Center for Plant Systems Biology, 9052, Ghent, Belgium, Gent.; Ghent University Expertise Centre for Transmission Electron Microscopy and VIB BioImaging Core, 9052, Ghent, Belgium.; Centro de Biologia Molecular Vegetal, Departamento de Biologia, Facultad de Ciencias, Universidad de Chile, 7800003, Santiago, Chile.; Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
Cell and tissue polarization is fundamental for plant growth and morphogenesis. The polar, cellular localization of Arabidopsis PIN-FORMED (PIN) proteins is crucial for their function in directional auxin transport. The clustering of PIN polar cargoes within the plasma membrane has been proposed to be important for the maintenance of their polar distribution. However, the more detailed features of PIN clusters and the cellular requirements of cargo clustering remain unclear. Here, we characterized PIN clusters in detail by means of multiple advanced microscopy and quantification methods, such as 3D quantitative imaging or freeze-fracture replica labeling. The size and aggregation types of PIN clusters were determined by electron microscopy at the nanometer level at different polar domains and at different developmental stages revealing a strong preference for clustering at the polar domains. Pharmacological and genetic studies revealed that PIN clusters depend on phosphoinositol pathways, cytoskeletal structures, and specific cell wall components as well as connections between the cell wall and the plasma membrane. Our work identifies the role of different cellular processes and structures in polar cargo clustering and provides an initial mechanistic insight into the polarity maintenance in plants and other systems.
PMID: 32810889
New Phytol , IF:8.512 , 2020 Aug doi: 10.1111/nph.16840
HBI1 acts downstream of ERECTA and SWR1 in regulating inflorescence architecture through the activation of the brassinosteroid and auxin signaling pathways.
Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Agriculture, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning, 530004, China.
Inflorescence architecture critically influences plant reproductive success and crop yield, and it reflects the activity of the inflorescence meristem and pedicel length. In Arabidopsis thaliana, the ERECTA (ER) signaling pathway and the SWR1 chromatin remodeling complex jointly regulate inflorescence architecture by promoting the expression of the PACLOBUTRAZOL RESISTANCE (PRE) gene family. However, how PREs regulate inflorescence architecture remains unclear. RNA-seq and chromatin immunoprecipitation coupled with quantitative PCR (ChIP-qPCR) analyses were performed. Genetic interactions between HOMOLOG OF BEE2 INTERACTING WITH IBH1 (HBI1) and SWR1-ER-MPK6 pathway in the control of Inflorescence architecture were further studied. The present findings support that HBI1 functions downstream of PREs in the SWR1 and ER pathways to regulate inflorescence architecture by promoting pedicel elongation. Specifically, it binds to the promoters of the brassinosteroid (BR) biosynthesis gene CYP85A2 and a series of auxin-related genes including auxin response factor ARF3 and promotes their expression. In turn, ARF3 can also bind to auxin signaling genes as well as CYP85A2 to activate their expression and promote pedicel elongation. Our study provides evidence that inflorescence architecture regulation by SWR1 and ER involves the HBI1 regulatory hub and its activation of both the BR and auxin hormone pathways.
PMID: 32746499
Cell Rep , IF:8.109 , 2020 Aug , V32 (8) : P108060 doi: 10.1016/j.celrep.2020.108060
Antagonistic Interaction between Auxin and SA Signaling Pathways Regulates Bacterial Infection through Lateral Root in Arabidopsis.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao 266237, Shandong, China. Electronic address: kongxiangpei@sdu.edu.cn.; The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao 266237, Shandong, China.; Department of Plant Pathology and the Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, China Agricultural University, Beijing 100193, China.; State Key Laboratory of Plant Genomics, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China.; Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China.; State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, China.; Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, Shandong, China.; The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao 266237, Shandong, China; State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, Shandong, China. Electronic address: dingzhaojun@sdu.edu.cn.
Pathogen entry into host tissues is a critical and first step in infections. In plants, the lateral roots (LRs) are a potential entry and colonization site for pathogens. Here, using a GFP-labeled pathogenic bacterium Pseudomonas syringae pv. tomato strain DC3000 (Pto DC3000), we observe that virulent Pto DC3000 invades plants through emerged LRs in Arabidopsis. Pto DC3000 strongly induced LR formation, a process that was dependent on the AUXIN RESPONSE FACTOR7 (ARF7)/ARF19-LATERAL ORGAN BOUNDARIES-DOMAIN (LBD) regulatory module. We show that salicylic acid (SA) represses LR formation, and several mutants defective in SA signaling are also involved in Pto DC3000-induced LR development. Significantly, ARF7, a well-documented positive regulator of LR development, directly represses the transcription of PR1 and PR2 to promote LR development. This study indicates that ARF7-mediated auxin signaling antagonizes with SA signaling to control bacterial infection through the regulation of LR development.
PMID: 32846118
PLoS Biol , IF:7.076 , 2020 Aug , V18 (8) : Pe3000830 doi: 10.1371/journal.pbio.3000830
Strigolactone signaling regulates specialized metabolism in tobacco stems and interactions with stem-feeding herbivores.
Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena, Germany.; Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, South Korea.; Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.; State Key Laboratory of Rice Biology, Institute of Insect Sciences, Zhejiang University, Hangzhou, China.; Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China.
Plants are attacked by herbivores, which often specialize on different tissues, and in response, have evolved sophisticated resistance strategies that involve different types of chemical defenses frequently targeted to different tissues. Most known phytohormones have been implicated in regulating these defenses, with jasmonates (JAs) playing a pivotal role in complex regulatory networks of signaling interactions, often generically referred to as "cross talk." The newly identified class of phytohormones, strigolactones (SLs), known to regulate the shoot architecture, remain unstudied with regard to plant-herbivore interactions. We explored the role of SL signaling in resistance to a specialist weevil (Trichobaris mucorea) herbivore of the native tobacco, Nicotiana attenuata, that attacks the root-shoot junction (RSJ), the part of the plant most strongly influenced by alterations in SL signaling (increased branching). As SL signaling shares molecular components, such as the core F-box protein more axillary growth 2 (MAX2), with another new class of phytohormones, the karrikins (KARs), which promote seed germination and seedling growth, we generated transformed lines, individually silenced in the expression of NaMAX2, dwarf 14 (NaD14: the receptor for SL) and carotenoid cleavage dioxygenase 7 (NaCCD7: a key enzyme in SL biosynthesis), and karrikin insensitive 2 (NaKAI2: the KAR receptor). The mature stems of all transgenic lines impaired in the SL, but not the KAR signaling pathway, overaccumulated anthocyanins, as did the stems of plants attacked by the larvae of weevil, which burrow into the RSJs to feed on the pith of N. attenuata stems. T. mucorea larvae grew larger in the plants silenced in the SL pathway, but again, not in the KAI2-silenced plants. These phenotypes were associated with elevated JA and auxin (indole-3-acetic acid [IAA]) levels and significant changes in the accumulation of defensive compounds, including phenolamides and nicotine. The overaccumulation of phenolamides and anthocyanins in the SL pathway-silenced plants likely resulted from antagonism between the SL and JA pathway in N. attenuata. We show that the repressors of SL signaling, suppressor of max2-like (NaSMXL6/7), and JA signaling, jasmonate zim-domain (NaJAZs), physically interact, promoting NaJAZb degradation and releasing jasmonate insensitive 1 (JIN1/MYC2) (NaMYC2), a critical transcription factor promoting JA responses. However, the increased performance of T. mucorea larvae resulted from lower pith nicotine levels, which were inhibited by increased IAA levels in SL pathway-silenced plants. This inference was confirmed by decapitation and auxin transport inhibitor treatments that decreased pith IAA and increased nicotine levels. In summary, SL signaling tunes specific sectors of specialized metabolism in stems, such as phenylpropanoid and nicotine biosynthesis, by tailoring the cross talk among phytohormones, including JA and IAA, to mediate herbivore resistance of stems. The metabolic consequences of the interplay of SL, JA, and IAA signaling revealed here could provide a mechanism for the commonly observed pattern of herbivore tolerance/resistance trade-offs.
PMID: 32810128
Plant Physiol , IF:6.902 , 2020 Aug doi: 10.1104/pp.20.00223
An ATP-binding cassette transporter, ABCB19, regulates leaf position and morphology during phototropin1-mediated blue light responses.
University of Maryland CITY: College Park STATE: Maryland POSTAL_CODE: 20742 United States Of America [US].; University of Maryland CITY: College Park STATE: Maryland United States Of America [US].; University of Maryland CITY: College Park STATE: Maryland POSTAL_CODE: 20742 United States Of America [US] asmurphy@umd.edu.
Blue light regulates multiple processes that optimize light capture and gas exchange in plants, including chloroplast movement, changes in stomatal conductance, and altered organ positioning. In Arabidopsis (Arabidopsis thaliana), these processes are primarily modulated by the blue light phototropin photoreceptors phot1 and phot2. Changes in leaf positioning and shape involve several signaling components that include NON-PHOTOTROPIC HYPOCOTYL3 (NPH3), PHYTOCHROME KINASE SUBSTRATE (PKS), ROOT PHOTOTROPISM2 (RPT2), and alterations in localized auxin streams. Direct phosphorylation of the auxin transporter ATP-BINDING CASSETTE subfamily B19 (ABCB19) by phot1 in phototropic seedlings suggests that phot1 may directly regulate ABCB19 to adjust auxin-dependent leaf responses. Here, abcb19 mutants were analyzed for fluence and blue light-dependent changes in leaf positioning and morphology. abcb19 displays upright petiole angles that remain unchanged in response to red and blue light. Similarly, abcb19 mutants develop irregularly wavy rosette leaves that are less sensitive to blue light-mediated leaf flattening. Visualization of auxin distribution, measurement of auxin transport in protoplasts, and direct quantification of free auxin levels suggest these irregularities are caused by misregulation of ABCB19-mediated auxin distribution in addition to light-dependent auxin biosynthesis.
PMID: 32855213
Plant Physiol , IF:6.902 , 2020 Aug doi: 10.1104/pp.20.00393
Melatonin is involved in citrus response to the pathogen Huanglongbing via modulation of phytohormonal biosynthesis.
University Of Florida, Citrus Research and Education Center CITY: Lake Alfred STATE: Florida United States Of America [US].; University Of Florida, Citrus Research and Education Center CITY: Lake Alfred STATE: Florida POSTAL_CODE: 33850 United States Of America [US] nabilkilliny@ufl.edu.
Huanglongbing (HLB) is a devastating citrus disease worldwide that is putatively caused by 'Candidatus Liberibacter asiaticus' and transmitted by Diaphorina citri. Melatonin is a ubiquitously distributed auxin-like metabolite found in both prokaryotes and eukaryotes. In this study, we used integrative metabolomic and transcriptomic approaches to investigate the potential role of melatonin in citrus response against HLB and to understand the relationships between melatonin and the stress-associated phytohormones at molecular and metabolic levels. Melatonin was detected in the leaves of 'Valencia' sweet orange (Citrus sinensis) after derivatization with N-methyl-N- trimethylsilyltrifluoroacetamide (MSTFA) using a targeted gas chromatography-mass spectrometry running in selective ion monitoring mode (GC-MS-SIM)-based method. 'Ca. L. asiaticus' infection and D. citri infestation significantly increased endogenous melatonin levels in citrus leaves and upregulated the expression of its biosynthetic genes (CsTDC, CsT5H, CsSNAT, CsASMT, and CsCOMT). However, infection with 'Ca. L. asiaticus' had a greater effect than did infestation with D. citri. Melatonin induction was positively correlated with salicylic acid content, but not that of trans-jasmonic acid. Moreover, melatonin supplementation enhanced the endogenous contents of the stress-associated phytohormones (salicylates, auxins, tJA, and abscisic acid) and the transcript levels of their biosynthetic genes. Furthermore, melatonin supplementation diminished the 'Ca. L. asiaticus' titer within the infected leaves, which suggests that melatonin might play an antibacterial role against this bacterium, and Gram-negative bacteria in general. These findings provide a better understanding of the melatonin-mediated defensive response against HLB via modulation of multiple hormonal pathways. Understanding the role of melatonin in citrus defense to HLB may provide a novel therapeutic strategy to mitigate the disease.
PMID: 32843523
Plant Physiol , IF:6.902 , 2020 Aug doi: 10.1104/pp.20.00799
PI4Kgamma2 interacts with E3 ligase MIEL1 to regulate auxin metabolism and root development.
Shanghai Jiao Tong University CITY: Shanghai China [CN].; Shanghai Jiao Tong University CITY: Shanghai POSTAL_CODE: 200240 China [CN] hwxue@sjtu.edu.cn.
Root development is important for normal plant growth and nutrient absorption. Studies have revealed the involvement of various factors in this complex process, improving our understanding of the relevant regulatory mechanisms. Here, we functionally characterize the role of Arabidopsis phosphatidylinositol 4-kinase gamma2 (PI4Kgamma2) in root elongation regulation, which functions to modulate stability of the RING-type E3 ligase MYB30-INTERACTING E3 LIGASE 1 (MIEL1) and auxin metabolism. Mutant plants deficient in PI4Kgamma2 (pi4kgamma2) exhibited a shortened root length and elongation zone due to reduced auxin level. PI4Kgamma2 was shown to interact with MIEL1, regulating its degradation and further the stability of transcription factor MYB30, which suppresses auxin metabolism by directly binding to promoter regions of GH3.2 and GH3.6. Interestingly, pi4kgamma2 plants presented altered hypersensitive response, indicating that PI4Kgamma2 regulates synergetic growth and defense of plants through modulating auxin metabolism. These results reveal the importance of protein interaction in regulating ubiquitin-mediated protein degradation in eukaryotic cells, and illustrate a mechanism coordinating plant growth and biotic stress response.
PMID: 32788299
J Exp Bot , IF:5.908 , 2020 Aug , V71 (16) : P4763-4777 doi: 10.1093/jxb/eraa256
The amino acid transporter AAP1 mediates growth and grain yield by regulating neutral amino acid uptake and reallocation in Oryza sativa.
State Key Laboratory of Genetic Engineering, Department of Genetics, School of Life Sciences, Fudan University, Shanghai, China.; Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Agricultural Sciences, Guizhou University, Guiyang, China.; National Key Laboratory of Crop Genetic Improvement, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
Nitrogen (N) is a major element necessary for crop yield. In most plants, organic N is primarily transported in the form of amino acids. Here, we show that amino acid permease 1 (AAP1) functions as a positive regulator of growth and grain yield in rice. We found that the OsAAP1 gene is highly expressed in rice axillary buds, leaves, and young panicles, and that the OsAAP1 protein is localized to both the plasma membrane and the nuclear membrane. Compared with the wild-type ZH11, OsAAP1 overexpression (OE) lines exhibited increased filled grain numbers as a result of enhanced tillering, while RNAi and CRISPR (clustered regularly interspaced short palindromic repeat; Osaap1) knockout lines showed the opposite phenotype. In addition, OsAAP1-OE lines had higher concentrations of neutral and acidic amino acids, but lower concentrations of basic amino acids in the straw. An exogenous treatment with neutral amino acids promoted axillary bud outgrowth more strongly in the OE lines than in the WT, RNAi, or Osaap1 lines. Transcriptome analysis of Osaap1 further demonstrated that OsAAP1 may affect N transport and metabolism, and auxin, cytokinin, and strigolactone signaling in regulating rice tillering. Taken together, these results support that increasing neutral amino acid uptake and reallocation via OsAAP1 could improve growth and grain yield in rice.
PMID: 32485736
J Exp Bot , IF:5.908 , 2020 Aug , V71 (16) : P4843-4857 doi: 10.1093/jxb/eraa195
A glutathione-dependent control of the indole butyric acid pathway supports Arabidopsis root system adaptation to phosphate deprivation.
Universite Perpignan Via Domitia, Laboratoire Genome et Developpement des Plantes, UMR, Perpignan, France.; CNRS, Laboratoire Genome et Developpement des Plantes, UMR, Perpignan, France.; NSF Science and Technology Center for Engineering Mechanobiology, Department of Biology, Washington University in St. Louis, St. Louis, MO, USA.
Root system architecture results from a highly plastic developmental process to adapt to environmental conditions. In particular, the development of lateral roots and root hair growth are constantly optimized to the rhizosphere properties, including biotic and abiotic constraints. The development of the root system is tightly controlled by auxin, the driving morphogenic hormone in plants. Glutathione, a major thiol redox regulator, is also critical for root development but its interplay with auxin is scarcely understood. Previous work showed that glutathione deficiency does not alter root responses to indole acetic acid (IAA), the main active auxin in plants. Because indole butyric acid (IBA), another endogenous auxinic compound, is an important source of IAA for the control of root development, we investigated the crosstalk between glutathione and IBA during root development. We show that glutathione deficiency alters lateral roots and root hair responses to exogenous IBA but not IAA. Detailed genetic analyses suggest that glutathione regulates IBA homeostasis or conversion to IAA in the root cap. Finally, we show that both glutathione and IBA are required to trigger the root hair response to phosphate deprivation, suggesting an important role for this glutathione-dependent regulation of the auxin pathway in plant developmental adaptation to its environment.
PMID: 32309856
Int J Mol Sci , IF:4.556 , 2020 Aug , V21 (17) doi: 10.3390/ijms21175955
The Plasticity of Root Systems in Response to External Phosphate.
Joint International Research Laboratory of Metabolic & Developmental Sciences, SJTU-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.; School of Agriculture, University of Adelaide-SJTU Joint Centre for Agriculture and Health, Food and Wine, University of Adelaide, Waite Campus, Urrbrae 5064, South Australia.
Phosphate is an essential macro-element for plant growth accumulated in the topsoil. The improvement of phosphate uptake efficiency via manually manipulating root system architecture is of vital agronomic importance. This review discusses the molecular mechanisms of root patterning in response to external phosphate availability, which could be applied on the alleviation of phosphate-starvation stress. During the long time evolution, plants have formed sophisticated mechanisms to adapt to environmental phosphate conditions. In terms of root systems, plants would adjust their root system architecture via the regulation of the length of primary root, the length/density of lateral root and root hair and crown root growth angle to cope with different phosphate conditions. Finally, plants develop shallow or deep root system in low or high phosphate conditions, respectively. The plasticity of root system architecture responds to the local phosphate concentrations and this response was regulated by actin filaments, post-translational modification and phytohormones such as auxin, ethylene and cytokinin. This review summarizes the recent progress of adaptive response to external phosphate with focus on integrated physiological, cellular and molecular signaling transduction in rice and Arabidopsis.
PMID: 32824996
Int J Mol Sci , IF:4.556 , 2020 Aug , V21 (16) doi: 10.3390/ijms21165914
Comparative Transcriptomic Analysis of the Development of Sepal Morphology in Tomato (Solanum Lycopersicum L.).
College of Horticulture, Northwest A&F University, Shaanxi 712100, China.; State Agriculture Ministry Laboratory of Northwest Horticultural Plant Germplasm Resources & Genetic Improvement, Northwest A&F University, Shaanxi 712100, China.; Genetics Department, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt.
Sepal is an important component of the tomato flower and fruit that typically protects the flower in bud and functions as a support for petals and fruits. Moreover, sepal appearance influences the commercial property of tomato nowadays. However, the phenotype information and development mechanism of the natural variation of sepal morphology in the tomato is still largely unexplored. To study the developmental mechanism and to determine key genes related to downward sepal in the tomato, we compared the transcriptomes of sepals between downward sepal (dsp) mutation and the wild-type by RNA sequencing and found that the differentially expressed genes were dominantly related to cell expansion, auxin, gibberellins and cytokinin. dsp mutation affected cell size and auxin, and gibberellins and cytokinin contents in sepals. The results showed that cell enlargement or abnormal cell expansion in the adaxial part of sepals in dsp. As reported, auxin, gibberellins and cytokinin were important factors for cell expansion. Hence, dsp mutation regulated cell expansion to control sepal morphology, and auxin, gibberellins and cytokinin may mediate this process. One ARF gene and nine SAUR genes were dramatically upregulated in the sepal of the dsp mutant, whereas seven AUX/IAA genes were significantly downregulated in the sepal of dsp mutant. Further bioinformatic analyses implied that seven AUX/IAA genes might function as negative regulators, while one ARF gene and nine SAUR genes might serve as positive regulators of auxin signal transduction, thereby contributing to cell expansion in dsp sepal. Thus, our data suggest that 17 auxin-responsive genes are involved in downward sepal formation in the tomato. This study provides valuable information for dissecting the molecular mechanism of sepal morphology control in the tomato.
PMID: 32824631
Int J Mol Sci , IF:4.556 , 2020 Aug , V21 (16) doi: 10.3390/ijms21165679
Phenylpropanoids Are Connected to Cell Wall Fortification and Stress Tolerance in Avocado Somatic Embryogenesis.
Red de Manejo Biotecnologico de Recursos, Instituto de Ecologia A. C., Cluster BioMimic(R), Carretera Antigua a Coatepec 351, Congregacion el Haya, Xalapa, Veracruz CP 91073, Mexico.; Tecnologico Nacional de Mexico, Instituto Tecnologico de Veracruz, Unidad de Investigacion y Desarrollo en Alimentos, Veracruz CP 91897, Mexico.; Instituto Politecnico Nacional, Centro Interdisciplinario de Investigacion para el Desarrollo Integral Regional-Unidad Sinaloa, Boulevard Juan de Dios Batiz Paredes # 250, Col. San Joachin, Guasave, Sinaloa 81101, Mexico.; European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire CB10 1SD, UK.; Department of Horticultural Science, University of Minnesota, Saint Paul, MN 55108, USA.; Unidad de Bioquimica y Biologia Molecular de Plantas, Centro de Investigacion Cientifica de Yucatan, Merida, Yucatan CP 97205, Mexico.; Red de Estudios Moleculares Avanzados, Instituto de Ecologia A. C., Cluster BioMimic(R), Carretera Antigua a Coatepec 351, Congregacion el Haya, Xalapa, Veracruz CP 91073, Mexico.
Somatic embryogenesis (SE) is a valuable model for understanding the mechanism of plant embryogenesis and a tool for the mass production of plants. However, establishing SE in avocado has been complicated due to the very low efficiency of embryo induction and plant regeneration. To understand the molecular foundation of the SE induction and development in avocado, we compared embryogenic (EC) and non-embryogenic (NEC) cultures of two avocado varieties using proteomic and metabolomic approaches. Although Criollo and Hass EC exhibited similarities in the proteome and metabolome profile, in general, we observed a more active phenylpropanoid pathway in EC than NEC. This pathway is associated with the tolerance of stress responses, probably through the reinforcement of the cell wall and flavonoid production. We could corroborate that particular polyphenolics compounds, including p-coumaric acid and t-ferulic acid, stimulated the production of somatic embryos in avocado. Exogen phenolic compounds were associated with the modification of the content of endogenous polyphenolic and the induction of the production of the putative auxin-a, adenosine, cellulose and 1,26-hexacosanediol-diferulate. We suggest that in EC of avocado, there is an enhanced phenylpropanoid metabolism for the production of the building blocks of lignin and flavonoid compounds having a role in cell wall reinforcement for tolerating stress response. Data are available at ProteomeXchange with the identifier PXD019705.
PMID: 32784357
Int J Mol Sci , IF:4.556 , 2020 Aug , V21 (15) doi: 10.3390/ijms21155554
Expression and Role of Biosynthetic, Transporter, Receptor, and Responsive Genes for Auxin Signaling during Clubroot Disease Development.
Department of Horticulture, Sunchon National University, Suncheon 57922, Korea.; Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh 02202, Bangladesh.; Department of Agronomy, Patuakhali Science and Technology University, Patuakhali 8602, Bangladesh.
Auxins play a pivotal role in clubroot development caused by the obligate biotroph Plasmodiophora brassicae. In this study, we investigated the pattern of expression of 23 genes related to auxin biosynthesis, reception, and transport in Chinese cabbage (Brassica rapa) after inoculation with P. brassicae. The predicted proteins identified, based on the 23 selected auxin-related genes, were from protein kinase, receptor kinase, auxin responsive, auxin efflux carrier, transcriptional regulator, and the auxin-repressed protein family. These proteins differed in amino acids residue, molecular weights, isoelectric points, chromosomal location, and subcellular localization. Leaf and root tissues showed dynamic and organ-specific variation in expression of auxin-related genes. The BrGH3.3 gene, involved in auxin signaling, exhibited 84.4-fold increase in expression in root tissues compared to leaf tissues as an average of all samples. This gene accounted for 4.8-, 2.6-, and 5.1-fold higher expression at 3, 14, and 28 days post inoculation (dpi) in the inoculated root tissues compared to mock-treated roots. BrNIT1, an auxin signaling gene, and BrPIN1, an auxin transporter, were remarkably induced during both cortex infection at 14 dpi and gall formation at 28 dpi. BrDCK1, an auxin receptor, was upregulated during cortex infection at 14 dpi. The BrLAX1 gene, associated with root hair development, was induced at 1 dpi in infected roots, indicating its importance in primary infection. More interestingly, a significantly higher expression of BrARP1, an auxin-repressed gene, at both the primary and secondary phases of infection indicated a dynamic response of the host plant towards its resistance against P. brassicae. The results of this study improve our current understanding of the role of auxin-related genes in clubroot disease development.
PMID: 32756478
Theor Appl Genet , IF:4.439 , 2020 Aug doi: 10.1007/s00122-020-03667-0
Differential expression of transcription factor- and further growth-related genes correlates with contrasting cluster architecture in Vitis vinifera 'Pinot Noir' and Vitis spp. genotypes.
Federal Research Centre for Cultivated Plants, Institute for Grapevine Breeding Geilweilerhof, Julius Kuhn Institute, 76833, Siebeldingen, Germany.; Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding, Carl-von-Linne-Weg 10, 50829, Cologne, Germany.; Federal Research Centre for Cultivated Plants, Institute for Crop and Soil Science, Julius Kuhn Institute, Bundesallee 58, 38116, Brunswick, Germany.; Federal Research Centre for Cultivated Plants, Institute for Grapevine Breeding Geilweilerhof, Julius Kuhn Institute, 76833, Siebeldingen, Germany. eva.zyprian@julius-kuehn.de.
Grapevine (Vitis vinifera L.) is an economically important crop that needs to comply with high quality standards for fruit, juice and wine production. Intense plant protection is required to avoid fungal damage. Grapevine cultivars with loose cluster architecture enable reducing protective treatments due to their enhanced resilience against fungal infections, such as Botrytis cinerea-induced gray mold. A recent study identified transcription factor gene VvGRF4 as determinant of pedicel length, an important component of cluster architecture, in samples of two loose and two compact quasi-isogenic 'Pinot Noir' clones. Here, we extended the analysis to 12 differently clustered 'Pinot Noir' clones from five diverse clonal selection programs. Differential gene expression of these clones was studied in three different locations over three seasons. Two phenotypically opposite clones were grown at all three locations and served for standardization. Data were correlated with the phenotypic variation of cluster architecture sub-traits. A set of 14 genes with consistent expression differences between loosely and compactly clustered clones-independent from season and location-was newly identified. These genes have annotations related to cellular growth, cell division and auxin metabolism and include two more transcription factor genes, PRE6 and SEP1-like. The differential expression of VvGRF4 in relation to loose clusters was exclusively found in 'Pinot Noir' clones. Gene expression studies were further broadened to phenotypically contrasting F1 individuals of an interspecific cross and OIV reference varieties of loose cluster architecture. This investigation confirmed PRE6 and six growth-related genes to show differential expression related to cluster architecture over genetically divergent backgrounds.
PMID: 32812062
Front Plant Sci , IF:4.402 , 2020 , V11 : P1182 doi: 10.3389/fpls.2020.01182
Nitric Oxide Cooperates With Auxin to Mitigate the Alterations in the Root System Caused by Cadmium and Arsenic.
Department of Environmental Biology, "Sapienza" University of Rome, Rome, Italy.; Department of European and Mediterranean Cultures: Architecture, Environment, and Cultural Heritage (DICEM), University of Basilicata, Matera, Italy.
Oryza sativa L. is a worldwide food-crop frequently growing in cadmium (Cd)/arsenic (As) polluted soils, with its root-system as the first target of the pollutants. Root-system development involves the establishment of optimal indole-3-acetic acid (IAA) levels, also requiring the conversion of the IAA natural precursor indole-3-butyric acid (IBA) into IAA, causing nitric oxide (NO) formation. Nitric oxide is a stress-signaling molecule. In rice, a negative interaction of Cd or As with endogenous auxin has been demonstrated, as some NO protective effects. However, a synergism between the natural auxins (IAA and/or IBA) and NO was not yet determined and might be important for ameliorating rice metal(oid)-tolerance. With this aim, the stress caused by Cd/As toxicity in the root cells and the possible recovery by either NO or auxins (IAA/IBA) were evaluated after Cd or As (arsenate) exposure, combined or not with the NO-donor compound sodium-nitroprusside (SNP). Root fresh weight, membrane electrolyte leakage, and H2O2 production were also measured. Moreover, endogenous IAA/IBA contents, transcription-levels of OsYUCCA1 and OsASA2 IAA-biosynthetic-genes, and expression of the IAA-influx-carrier OsAUX1 and the IAA-responsive DR5::GUS construct were analyzed, and NO-epifluorescence levels were measured. Results showed that membrane injury by enhanced electrolyte leakage occurred under both pollutants and was reduced by the treatment with SNP only in Cd-presence. By contrast, no membrane injury was caused by either exogenous NO or IAA or IBA. Cd- and As-toxicity also resulted into a decreased root fresh weight, mitigated by the combination of each pollutant with either IAA or IBA. Cd and As decreased the endogenous NO-content, increased H2O2 formation, and altered auxin biosynthesis, levels and distribution in both adventitious (ARs) and mainly lateral roots (LRs). The SNP-formed NO counteracted the pollutants' effects on auxin distribution/levels, reduced H2O2 formation in Cd-presence, and enhanced AUX1-expression, mainly in As-presence. Each exogenous auxin, but mainly IBA, combined with Cd or As at 10 microM, mitigated the pollutants' effects by increasing LR-production and by increasing NO-content in the case of Cd. Altogether, results demonstrate that NO and auxin(s) work together in the rice root system to counteract the specific toxic-effects of each pollutant.
PMID: 32849732
Mol Plant Pathol , IF:4.326 , 2020 Aug doi: 10.1111/mpp.12978
Cytokinin response induces immunity and fungal pathogen resistance, and modulates trafficking of the PRR LeEIX2 in tomato.
Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization, Rishon LeZion, Israel.; School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel.
Plant immunity is often defined by the immunity hormones: salicylic acid (SA), jasmonic acid (JA), and ethylene (ET). These hormones are well known for differentially regulating defence responses against pathogens. In recent years, the involvement of other plant growth hormones such as auxin, gibberellic acid, abscisic acid, and cytokinins (CKs) in biotic stresses has been recognized. Previous reports have indicated that endogenous and exogenous CK treatment can result in pathogen resistance. We show here that CK induces systemic immunity in tomato (Solanum lycopersicum), modulating cellular trafficking of the pattern recognition receptor (PRR) LeEIX2, which mediates immune responses to Xyn11 family xylanases, and promoting resistance to Botrytis cinerea and Oidium neolycopersici in an SA- and ET-dependent mechanism. CK perception within the host underlies its protective effect. Our results support the notion that CK promotes pathogen resistance by inducing immunity in the host.
PMID: 32841497
Biomolecules , IF:4.082 , 2020 Aug , V10 (9) doi: 10.3390/biom10091231
Rhizobacteria Inoculation Effects on Phytohormone Status of Potato Microclones Cultivated In Vitro under Osmotic Stress.
Ufa Institute of Biology, Ufa Federal Research Centre, Russian Academy of Sciences, Prospekt Oktyabrya, 69, 450054 Ufa, Russia.; Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Prospekt Entuziastov, 13, 410049 Saratov, Russia.; Vavilov Saratov State Agrarian University, Teatralnaya Square, 1, 410012 Saratov, Russia.
Water deficits inhibit plant growth and decrease crop productivity. Remedies are needed to counter this increasingly urgent problem in practical farming. One possible approach is to utilize rhizobacteria known to increase plant resistance to abiotic and other stresses. We therefore studied the effects of inoculating the culture medium of potato microplants grown in vitro with Azospirillum brasilense Sp245 or Ochrobactrum cytisi IPA7.2. Growth and hormone content of the plants were evaluated under stress-free conditions and under a water deficit imposed with polyethylene glycol (PEG 6000). Inoculation with either bacterium promoted the growth in terms of leaf mass accumulation. The effects were associated with increased concentrations of auxin and cytokinin hormones in the leaves and stems and with suppression of an increase in the leaf abscisic acid that PEG treatment otherwise promoted in the potato microplants. O. cytisi IPA7.2 had a greater growth-stimulating effect than A. brasilense Sp245 on stressed plants, while A. brasilense Sp245 was more effective in unstressed plants. The effects were likely to be the result of changes to the plant's hormonal balance brought about by the bacteria.
PMID: 32847137
Ann Bot , IF:4.005 , 2020 Aug , V126 (3) : P481-497 doi: 10.1093/aob/mcaa099
Differential regulatory pathways associated with drought-inhibition and post-drought recuperation of rhizome development in perennial grass.
College of Grassland Science and Technology, China Agricultural University, Beijing, PR China.; Department of Plant Biology and Pathology Rutgers, the State University of New Jersey, New Brunswick, NJ, USA.; College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, PR China.; College of Grassland Science, Gansu Agricultural University, Lanzhou, PR China.
BACKGROUND AND AIMS: Rhizomes are key organs for the establishment of perennial grass stands and adaptation to environmental stress. However, mechanisms regulating rhizome initiation and elongation under drought stress and during post-drought recovery remain unclear. The objective of this study is to investigate molecular factors and metabolic processes involved in drought effects and post-drought recovery in rhizome growth in perennial grass species by comparative transcriptomic and proteomic profiling. METHODS: Tall fescue (Festuca arundinacea) (B-type rhizome genotype, 'BR') plants were exposed to drought stress and re-watering in growth chambers. The number and length of rhizomes were measured following drought stress and re-watering. Hormone and sugar contents were analysed, and transcriptomic and proteomic analyses were performed to identify metabolic factors, genes and proteins associated with rhizome development. KEY RESULTS: Rhizome initiation and elongation were inhibited by drought stress, and were associated with increases in the contents of abscisic acid (ABA) and soluble sugars, but declines in the contents of indoleacetic acid (IAA), zeatin riboside (ZR) and gibberellin (GA4). Genes involved in multiple metabolic processes and stress defence systems related to rhizome initiation exhibited different responses to drought stress, including ABA signalling, energy metabolism and stress protection. Drought-inhibition of rhizome elongation could be mainly associated with the alteration of GA4 and antioxidants contents, energy metabolism and stress response proteins. Upon re-watering, new rhizomes were regenerated from rhizome nodes previously exposed to drought stress, which was accompanied by the decline in ABA content and increases in IAA, ZR and GA4, as well as genes and proteins for auxin, lipids, lignin and nitrogen metabolism. CONCLUSIONS: Drought-inhibition of rhizome initiation and elongation in tall fescue was mainly associated with adjustments in hormone metabolism, carbohydrate metabolism and stress-defence systems. Rhizome regeneration in response to re-watering involved reactivation of hormone and lipid metabolism, secondary cell-wall development, and nitrogen remobilization and cycling.
PMID: 32445476
Sci Rep , IF:3.998 , 2020 Aug , V10 (1) : P13934 doi: 10.1038/s41598-020-70882-6
Molecular insights into biochar-mediated plant growth promotion and systemic resistance in tomato against Fusarium crown and root rot disease.
Department of Plant Pathology and Weed Research, Institute of Plant Protection, The Volcani Center (ARO), 7505101, Rishon Lezion, Israel.; Department of Soil Chemistry, Plant Nutrition and Microbiology, Institute of Soil, Water and Environmental Sciences, The Volcani Center (ARO), 7505101, Rishon Lezion, Israel.; Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 761001, Rehovot, Israel.; Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN, USA.; Department of Postharvest Science of Fresh Produce, Institute of Plant Harvest and Food Sciences, The Volcani Center (ARO), 7505101, Rishon Lezion, Israel.; Department of Plant Pathology and Weed Research, Institute of Plant Protection, The Volcani Center (ARO), 7505101, Rishon Lezion, Israel. omerf@volcani.agri.gov.il.
Molecular mechanisms associated with biochar-elicited suppression of soilborne plant diseases and improved plant performance are not well understood. A stem base inoculation approach was used to explore the ability of biochar to induce systemic resistance in tomato plants against crown rot caused by a soilborne pathogen, Fusarium oxysporum f. sp. radicis lycopersici. RNA-seq transcriptome profiling of tomato, and experiments with jasmonic and salycilic acid deficient tomato mutants, were performed to elucidate the in planta molecular mechanisms involved in induced resistance. Biochar (produced from greenhouse plant wastes) was found to mediate systemic resistance against Fusarium crown rot and to simultaneously improve tomato plant growth and physiological parameters by up to 63%. Transcriptomic analysis (RNA-seq) of tomato demonstrated that biochar had a priming effect on gene expression and upregulated the pathways and genes associated with plant defense and growth such as jasmonic acid, brassinosteroids, cytokinins, auxin and synthesis of flavonoid, phenylpropanoids and cell wall. In contrast, biosynthesis and signaling of the salicylic acid pathway was downregulated. Upregulation of genes and pathways involved in plant defense and plant growth may partially explain the significant disease suppression and improvement in plant performance observed in the presence of biochar.
PMID: 32811849
Analyst , IF:3.978 , 2020 Aug , V145 (17) : P5925-5932 doi: 10.1039/d0an00269k
A fish scale-like magnetic nanomaterial as a highly efficient sorbent for monitoring the changes in auxin levels under cadmium stress.
Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China. 196419@fzu.edu.cn zlan@fzu.edu.cn.
Sorbents with high surface utilization and good dispersibility are of great importance for the extraction performance of magnetic solid-phase extraction (MSPE). In this study, a fish scale-like magnetic nanomaterial (Co@Co3O4/OCN) was synthesized, which can be used as a highly efficient MSPE sorbent due to its strong magnetism, special morphology, doping of N element, numerous micro-mesopore cavities and organic functional groups (hydroxyl and carboxyl). Furthermore, a Co@Co3O4/OCN-based MSPE method for monitoring the changes in the levels of three auxins (indole-3-acetic acid, indole-3-propionic acid and 3-indole butyric acid) was successfully established. Wide linear ranges (1.0-1000.0 pg mL-1) with good correlation coefficients (R > 0.9992), low limits of detection (LODs, 0.2-4.0 pg mL-1) and satisfactory repeatability (RSD
PMID: 32692339
Genes (Basel) , IF:3.759 , 2020 Aug , V11 (8) doi: 10.3390/genes11080919
Brassinosteroid Priming Improves Peanut Drought Tolerance via Eliminating Inhibition on Genes in Photosynthesis and Hormone Signaling.
Guangdong Key Laboratory of Plant Molecular Breeding, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture, South China Agricultural University, Guangzhou 510642, China.; Department of Genetics, University of Georgia, Athens, GA 30602, USA.
Drought negatively affects the growth and yield of terrestrial crops. Seed priming, pre-exposing seed to a compound, could induce improved tolerance and adaptation to stress in germinated plants. To understand the effects and regulatory mechanism of seed priming with brassinosteroid (BR) on peanut plants, we treated seeds with five BR concentrations and examined dozens of physiological and biochemical features, and transcriptomic changes in leaves under well-watered and drought conditions. We found optimal 0.15 ppm BR priming could reduce inhibitions from drought and increase the yield of peanut, and priming effects are dependent on stage of plant development and duration of drought. BR priming induced fewer differentially expressed genes (DEGs) than no BR priming under well-watered condition. Drought with BR priming reduced the number of DEGs than drought only. These DEGs were enriched in varied gene ontologies and metabolism pathways. Downregulation of DEGs involved in both light perceiving and photosynthesis in leaves is consistent with low parameters of photosynthesis. Optimal BR priming partially rescued the levels of growth promoting auxin and gibberellin which were largely reduced by drought, and increased levels of defense associated abscisic acid and salicylic acid after long-term drought. BR priming induced many DEGs which function as kinase or transcription factor for signal cascade under drought. We proposed BR priming-induced regulatory responses will be memorized and recalled for fast adaptation in later drought stress. These results provide physiological and regulatory bases of effects of seed priming with BR, which can help to guide the framing improvement under drought stress.
PMID: 32796553
Plant Physiol Biochem , IF:3.72 , 2020 Aug , V155 : P512-522 doi: 10.1016/j.plaphy.2020.08.001
Transcriptional analysis reveals potential genes and regulatory networks involved in salicylic acid-induced flowering in duckweed (Lemna gibba).
Institute of Tropical Bioscience and Biotechnology, MOA Key Laboratory of Tropical Crops Biology and Genetic Resources, Hainan Bioenergy Center, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China; Hainan Key Laboratory for Protection and Utilization of Tropical Bioresources, Hainan Institute for Tropical Agricultural Resources, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China. Electronic address: fulili@itbb.org.cn.; Institute of Tropical Bioscience and Biotechnology, MOA Key Laboratory of Tropical Crops Biology and Genetic Resources, Hainan Bioenergy Center, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China; Hainan Key Laboratory for Protection and Utilization of Tropical Bioresources, Hainan Institute for Tropical Agricultural Resources, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China. Electronic address: tandeguan@itbb.org.cn.; Institute of Tropical Bioscience and Biotechnology, MOA Key Laboratory of Tropical Crops Biology and Genetic Resources, Hainan Bioenergy Center, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China; Hainan Key Laboratory for Protection and Utilization of Tropical Bioresources, Hainan Institute for Tropical Agricultural Resources, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China. Electronic address: sunxuepiao@itbb.org.cn.; Institute of Tropical Bioscience and Biotechnology, MOA Key Laboratory of Tropical Crops Biology and Genetic Resources, Hainan Bioenergy Center, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China; Hainan Key Laboratory for Protection and Utilization of Tropical Bioresources, Hainan Institute for Tropical Agricultural Resources, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China. Electronic address: dingzehong@itbb.org.cn.; Institute of Tropical Bioscience and Biotechnology, MOA Key Laboratory of Tropical Crops Biology and Genetic Resources, Hainan Bioenergy Center, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China; Hainan Key Laboratory for Protection and Utilization of Tropical Bioresources, Hainan Institute for Tropical Agricultural Resources, Chinese Academy of Tropical Agricultural Sciences, Xueyuan Road 4, Haikou, 571101, China. Electronic address: zhangjiaming@itbb.org.cn.
Duckweed is a simple aquatic floating plant having great potential in sewage treatment and bioenergy production. Duckweed rarely flowers in nature, which greatly limits its germplasm collection, conservation, and heterosis usage. Salicylic acid (SA) can efficiently induce flowering of duckweed (e.g., Lemna gibba); however, the related genes and regulatory networks remain unclear. In this work, we demonstrated that L. gibba flowering induced by SA was photoperiod-dependent, stress-involved, and abscisic acid (ABA)-disrupted. Totally 202, 78, and 413 differentially expressed (DE) genes were up-regulated, while 429, 72, and 307 were down-regulated at flower induction, flower initiation, and flowering stages, respectively. At the flower induction stage, the down-regulated genes were mainly involved in cell wall, auxin and ABA, light reaction, and abiotic stress, while the up-regulated genes were involved in development, brassinosteroid, major CHO metabolism, and redox. At the flower initiation stage, the down-regulated genes were enriched in light reaction and lipid metabolism, whereas the up-regulated genes were enriched in starch degradation and Ca(2+) signaling. At the flowering stage, the down-regulated genes were significantly enriched in photosynthesis, gibberellic acid, starch synthesis, nitrogen metabolism, and redox, while the up-regulated genes were enriched in cell wall, jasmonic acid, secondary metabolism, and Ca(2+) signaling. Besides, 46 transcription factors and 13 flowering-related DE genes were identified. Finally, a possible floral pathway, where LgTEM1, LgSVP, and LgFT1 might play critical roles in SA-induced flowering in L. gibba, was discussed. These findings provide a useful foundation for further investigation of genes and regulatory networks of SA-induced flowering in duckweed.
PMID: 32836197
Plant Physiol Biochem , IF:3.72 , 2020 Aug , V155 : P502-511 doi: 10.1016/j.plaphy.2020.08.003
Paclobutrazol elevates auxin and abscisic acid, reduces gibberellins and zeatin and modulates their transporter genes in Marubakaido apple (Malus prunifolia Borkh. var. ringo Asami) rootstocks.
Graduate School of Horticulture, Chiba University, Matsudo, 271-8510, Japan.; Center for Environment, Health and Field Sciences, Chiba University, Kashiwa, 277-0882, Japan.; Graduate School of Horticulture, Chiba University, Matsudo, 271-8510, Japan. Electronic address: s-kondo@faculty.chiba-u.jp.
To examine the dwarfing mechanism in apples, one-year-old Marubakaido (Malus prunifolia Borkh.) (invigorating) apple rootstock stools were foliar-sprayed with 860 mg L(-1) of paclobutrazol (PBZ) as a single application or without. M.9 apple rootstock (dwarf) was used as a positive control. The phytohormones were estimated in the shoot bark and sub-apical shoot and gene expression in the apices of terminal shoots. Evident responses to PBZ were observed a fortnight after treatment, as the shoot and internode lengths were suppressed significantly. Endogenous indole-3-acetic acid increased in the PBZ treatment, and the polar auxin transporter genes MdPIN1 and MdLAX1 and the biosynthesis gene MdYUCCA10a were upregulated along with the MdARF2 gene. Additionally, PBZ increased the abscisic acid (ABA) concentration and the biosynthesis-related gene MdNCED1 but repressed the degradation gene MdCYP707A1. The ABA transporter gene MdAITb-like was upregulated by PBZ. The concentrations of the gibberellins (GAs) GA1 and GA4 decreased in the PBZ-treated rootstocks. The GA transporter gene MdNFP3.1-like and the signaling gene MdGID1b-like were strongly downregulated by PBZ, whereas the catabolic gene MdGA2OX2 was upregulated. PBZ treatment significantly reduced trans-zeatin (tZ) levels and downregulated the cytokinin biosynthesis gene MdIPT6 but upregulated the MdCKX7 degradation gene. Additionally, PBZ upregulated the cytokinin-related transporter genes MdPUP7-like and MdPUP9-like. Collectively, our results show that the physiological and molecular effect of PBZ was observed within two weeks, and this was indicated by the modulation of phytohormonal levels as well as transporter and other gene expression in Marubakaido apple rootstocks.
PMID: 32836196
Plant Physiol Biochem , IF:3.72 , 2020 Aug , V155 : P444-454 doi: 10.1016/j.plaphy.2020.07.014
Auxinic herbicide conjugates with an alpha-amino acid function: Structural requirements for biological activity on motor cells.
Laboratoire EBI (Ecologie et Biologie des Interactions), UMR CNRS EBI 6267, Equipe SEVE (Sucres, Echanges Vegetaux, Environnement) du Transport, Universite de Poitiers, 3 rue Jacques Fort, TSA 51106, F-86073, Poitiers, Cedex 9, France.; IC2MP (Institut de Chimie des Milieux et des Materiaux de Poitiers), UMR CNRS 7285, Universite de Poitiers, 4 rue Michel Brunet, TSA 51106, F-86073, Poitiers, Cedex 9, France. Electronic address: jean.francois.chollet@univ-poitiers.fr.
Two Fabaceae exhibiting rapid osmocontractile pulvinar movements were used in this study because this activity is modified by natural auxin and dramatically by 2,4D. A short chain with a carboxylic group being required for auxinic properties, a critical point to analyze is whether the recently synthesized proherbicide epsilon-(2,4-dichlorophenoxyacetyl)-L-Lys (2-4D-L-Lys) maintains some biological activity despite the increase in length of the chain and the substitution of the carboxyl group by an alpha-amino acid function. No trace of 2,4D could be detected in the pulvinar tissues treated for 1 h with 2,4D-L-Lys. Complementary approaches (electrophysiology, pH measurements, use of plasma membrane vesicles) suggest that it was less efficient than 2,4D to activate the plasma membrane H(+)-ATPase (PM-H(+)-ATPase). However, it modified the various ion-driven reactions of Mimosa pudica and Cassia fasciculata pulvini in a similar way as 2,4D. Additionally, it was much more effective than fusicoccin to inhibit seismonastic movements of M. pudica leaves and, at low concentrations, to promote leaflet opening in dark, indicating that its mode of action is more complex than the only activation of the PM-H(+)-ATPase. Various substitutions on 2,4D-L-Lys affected its activity in correlation with the molecular descriptor "halogen ratio" of these derivatives. Conjugation with D-Lys also led to a decrease of pulvinar reaction, suggesting that 2,4D-Lys maintains the main signaling properties of 2,4D involved in pulvinar movements providing that the terminal zwitterion is in a suitable orientation. Our data guide future investigations on the effect of 2,4D and 2,4D-L-Lys on the vacuolar pump activity of motor cells.
PMID: 32818792
Mol Plant Microbe Interact , IF:3.696 , 2020 Aug doi: 10.1094/MPMI-08-20-0211-R
Validamycin A induces broad-spectrum resistance involving in salicylic acid, and jasmonic acid/ ethylene signaling pathways.
college of plant protection, Nanjing agricultural university, No.1 weigang, Nanjing, Nanjing, Jiangsu, China, 210095; 2016202042@njau.edu.cn.; Nanjing Agricultural University, 70578, Plant Protection, Weigang No.1, Nanjing, Jiangsu, China, 210095; dyb@njau.edu.cn.; Nanjing Agricultural University, 70578, Plant Protection, Nanjing, Jiangsu, China; 2018802235@njau.edu.cn.; Nanjing Agricultural University, 70578, Plant Protection, Nanjing, Jiangsu, China; 2018102140@njau.edu.cn.; Nanjing Agricultural University, 70578, Plant Protection, Nanjing, Jiangsu, China; jlz489@163.com.; Weigang No.1NanjingNanjing, China, 210095; houyiping@njau.edu.cn.; Nanjing Agricultural University, 70578, Plant Protection, Nanjing, Jiangsu, China; songxs@njau.edu.cn.; College of Plant Protection, Nanjing Agricultural University, College of Plant protection, Nanjing, Jiangsu, China; mgzhou@njau.edu.cn.
Validamycin A (VMA) is an aminoglycoside antibiotic used to control rice sheath blight. Although it has been reported that VMA can induce the plant defense responses, the mechanism remains poorly understood. Here we found that reactive oxygen species (ROS) bursts and callose deposition in Arabidopsis thaliana, rice (Oryza sativa L.) and wheat (Triticum aestivum L.) were induced by VMA and were most intense with 10 mug mL-1 of VMA at 24 h. Moreover, we showed that VMA induced resistance against Pseudomonas syringae, Botrytis cinerea, and Fusarium graminearum in Arabidopsis leaves, indicating that VMA induces broad-spectrum disease resistance in both dicots and monocots. Furtherly, VMA-mediated resistance against P. syringae was not induced in NahG transgenic plants, partially decreased in npr1 mutants, and VMA-mediated resistance to B. cinerea was not induced in npr1, jar1, and ein2 mutants. These results strongly indicated that VMA triggers plant defense responses to both biotrophic and necrotrophic pathogens involving in salicylic acid (SA), jasmonic acid/ ethylene (JA/ET) signaling pathway and dependent on NPR1. In addition, transcriptome analysis further revealed that VMA regulated the expressions of genes involved in SA, JA/ET, abscisic acid (ABA) and Auxin signal pathways. Taken together, VMA induces systemic resistance involving in SA, and JA/ET signaling pathways, and also exerts a positive influence on ABA and Auxin signaling pathways. Our study highlighted the creative application of VMA in triggering plant defense responses against plant pathogens, providing a valuable insight into applying VMA to enhance plant resistance and reduce the use of chemical pesticides.
PMID: 32815479
BMC Genomics , IF:3.594 , 2020 Aug , V21 (1) : P553 doi: 10.1186/s12864-020-06951-x
To bloom once or more times: the reblooming mechanisms of Iris germanica revealed by transcriptome profiling.
Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing, China.; Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing, China. gaoyk@bjfu.edu.cn.
BACKGROUND: The reblooming bearded iris (Iris germanica) can bloom twice a year, in spring and autumn. The extended ornamental period makes it more popular and brings additional commercial values. However, little is known about the reblooming mechanisms, making the breeding programs time-consuming and labor-wasting. Therefore, a comparative transcriptome profiling was conducted on once-bloomers and rebloomers from the same F1 generation on six development stages, and the candidate genes associated with reblooming were identified. RESULTS: A total of 100,391 unigenes were generated, the mean length being 785 bp. In the three comparisons (the floral initiation stage of spring flowering in once-bloomers (OB-T1) vs the floral initiation stage of spring flowering in rebloomers (RB-T1); RB-T1 vs the floral initiation stage of autumn flowering in rebloomers (RB-T5); OB-T1 vs RB-T5), a total of 690, 3515 and 2941 differentially expressed genes (DEGs) were annotated against the public databases, respectively. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis focused on the photoperiod response, the temperature insensitivity and the growth speed, to remove the redundant DEGs and figure out the candidate key genes. As a result, the following four genes, PHYTOCHROME A (PHYA), GIGANTEA (GI), SHORT VEGETATIVE PERIOD (SVP) and AUXIN RESPONSE FACTOR (ARF), were considered to be involved in the second floral initiation of the rebloomers. CONCLUSION: This research provides valuable information for the discovery of the reblooming-related genes. The insights into the molecular mechanisms of reblooming may accelerate the breeding of bearded iris and other perennials.
PMID: 32787785
BMC Plant Biol , IF:3.497 , 2020 Aug , V20 (1) : P384 doi: 10.1186/s12870-020-02591-1
Genome-wide identification and characterization of gibberellin metabolic and signal transduction (GA MST) pathway mediating seed and berry development (SBD) in grape (Vitis vinifera L.).
Nanjing Agricultural University, College of Horticulture, Nanjing, 210095, PR China.; China Agricultural University, College of Horticulture, Beijing, 100193, China.; Division of Crop Sciences, ICAR-Central Research Institute for Dryland Agriculture, Santoshnagar, Hyderabad, Telangana, 500059, India.; Institute of Pomology, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.; Nanjing Agricultural University, College of Horticulture, Nanjing, 210095, PR China. wangchen@njau.edu.cn.; Nanjing Agricultural University, College of Horticulture, Nanjing, 210095, PR China. 826507957@qq.com.
BACKGROUND: Grape is highly sensitive to gibberellin (GA), which is crucial during seed and berry development (SBD) either by itself or by interacting with other hormones, such as auxin, Abscisic acid (ABA), and Cytokinin (CK). However, no systematic analysis of GA metabolic and signal transduction (MST) pathway has been undertaken in grapevine. RESULTS: In this study, total endogenous GA3 content significantly decreased during SBD, and a total of 48 known genes in GA metabolic (GAM; 31) and signal transduction (ST; 17) pathways were identified in this process. In the GAM pathway, out of 31 genes, VvGA20ox1-1, VvGA3ox4-1, and VvGA2ox1-1 may be the major factors interacting at the green-berry stage (GBS) accompanied with higher accumulation rate. GA biosynthesis was greater than GA inactivation at GBS, confirming the importance of seeds in GA synthesis. The visible correlation between endogenous GA3 content and gene expression profiles suggested that the transcriptional regulation of GA biosynthesis pathway genes was a key mechanism of GA accumulation at the stone-hardening stage (SHS). Interestingly, we observed a negative feedback regulation between VvGA3oxs-VvGAI1-4, VvGA2oxs-VvGAI1-4, and VvGID1B-VvGAI1-4 in maintaining the balance of GA3 content in berries. Moreover, 11 miRNAs may be involved in the modulation of GA MST pathway by mediating their target genes, such as VvGA3ox, VvGID1B, and VvGAMYB. Many genes in auxin, ABA, and CK MST pathways were further identified and found to have a special pattern in the berry, and the crosstalk between GA and these hormones may modulate the complex process during SBD through the interaction gene network of the multihormone pathway. Lastly, based on the expression characterization of multihormone MST pathway genes, a proposed model of the GA-mediated multihormone regulatory network during SBD was proposed. CONCLUSIONS: Our results provided novel insights into GA-mediated regulatory networks during SBD in grape. The complexity of GA-mediated multihormone ST in SBD was also elucidated, thereby providing valuable information for future functional characterizations of specific genes in grape.
PMID: 32825825
Plant Mol Biol , IF:3.302 , 2020 Aug doi: 10.1007/s11103-020-01033-8
Integrative omics approaches revealed a crosstalk among phytohormones during tuberous root development in cassava.
RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan. yoshinori.utsumi@riken.jp.; RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.; RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.; Faculty of Agriculture, Yamagata University, Tsuruoka, Japan.; Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.; Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Chiba, 260-8675, Japan.; Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601, Japan.; Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand.; RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan. motoaki.seki@riken.jp.; RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. motoaki.seki@riken.jp.; Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama, Kanagawa, 244-0813, Japan. motoaki.seki@riken.jp.
KEY MESSAGE: Integrative omics approaches revealed a crosstalk among phytohormones during tuberous root development in cassava. Tuberous root formation is a complex process consisting of phase changes as well as cell division and elongation for radial growth. We performed an integrated analysis to clarify the relationships among metabolites, phytohormones, and gene transcription during tuberous root formation in cassava (Manihot esculenta Crantz). We also confirmed the effects of the auxin (AUX), cytokinin (CK), abscisic acid (ABA), jasmonic acid (JA), gibberellin (GA), brassinosteroid (BR), salicylic acid, and indole-3-acetic acid conjugated with aspartic acid on tuberous root development. An integrated analysis of metabolites and gene expression indicated the expression levels of several genes encoding enzymes involved in starch biosynthesis and sucrose metabolism are up-regulated during tuberous root development, which is consistent with the accumulation of starch, sugar phosphates, and nucleotides. An integrated analysis of phytohormones and gene transcripts revealed a relationship among AUX signaling, CK signaling, and BR signaling, with AUX, CK, and BR inducing tuberous root development. In contrast, ABA and JA inhibited tuberous root development. These phenomena might represent the differences between stem tubers (e.g., potato) and root tubers (e.g., cassava). On the basis of these results, a phytohormonal regulatory model for tuberous root development was constructed. This model may be useful for future phytohormonal studies involving cassava.
PMID: 32757126
Front Genet , IF:3.258 , 2020 , V11 : P881 doi: 10.3389/fgene.2020.00881
SlGID1a Is a Putative Candidate Gene for qtph1.1, a Major-Effect Quantitative Trait Locus Controlling Tomato Plant Height.
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China.; Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing, China.; Key Laboratory of Horticultural Crop Biology and Germplasm Innovation in South China, Ministry of Agriculture, College of Horticulture, South China Agricultural University, Guangzhou, China.
Plant height is an important agronomic trait in crops. Several genes underlying tomato (Solanum lycopersicum) plant height mutants have been cloned. However, few quantitative trait genes for plant height have been identified in tomato. In this study, seven quantitative trait loci (QTLs) controlling plant height were identified in tomato. Of which, qtph1.1 (QTL for tomato plant height 1.1), qtph3.1 and qtph12.1 were major QTLs and explained 15, 16, and 12% of phenotypic variation (R(2)), respectively. The qtph1.1 was further mapped to an 18.9-kb interval on chromosome 1. Based on the annotated tomato genome (version SL2.50, annotation ITAG2.40), Solyc01g098390 encoding GA receptor SlGID1a was the putative candidate gene. The SlGID1a gene underlying the qtph1.1 locus contained a single nucleotide polymorphism (SNP) that resulted in an amino acid alteration in protein sequence. The near-isogenic line containing the qtph1.1 locus (NIL-qtph1.1) exhibited shorter internode length and cell length than the wild type (NIL-WT). The dwarf phenotype of NIL-qtph1.1 could not be rescued by exogenous GA3 treatment. Transcriptome analysis and real-time quantitative reverse transcription PCR (qPCR) showed that several genes related to biosynthesis and signaling of GA and auxin were differentially expressed in stems between NIL-qtph1.1 and NIL-WT. These findings might pave the road for understanding the molecular regulation mechanism of tomato plant height.
PMID: 32849843
Environ Sci Pollut Res Int , IF:3.056 , 2020 Aug doi: 10.1007/s11356-020-10370-6
Herbicides based on 2,4-D: its behavior in agricultural environments and microbial biodegradation aspects. A review.
Instituto de Investigacion en Micologia y Micotoxicologia (IMICO-CONICET). Departamento de Microbiologia e Inmunologia, Facultad de Ciencias Exactas, Fisico, Quimicas y Naturales, Universidad Nacional de Rio Cuarto, Ruta Nacional N degrees 36 Km 601, 5800, Rio Cuarto, Cordoba, Argentina.; Instituto de Investigacion en Micologia y Micotoxicologia (IMICO-CONICET). Departamento de Microbiologia e Inmunologia, Facultad de Ciencias Exactas, Fisico, Quimicas y Naturales, Universidad Nacional de Rio Cuarto, Ruta Nacional N degrees 36 Km 601, 5800, Rio Cuarto, Cordoba, Argentina. cbarberis@exa.unrc.edu.ar.
One of the main herbicides used in the agricultural environments is 2,4-dichlorophenoxyacetic acid (2,4-D). It is a synthetic plant hormone auxin employed in many crops including rice, wheat, sorghum, sugar cane, and corn to control wide leaf weeds. The indiscriminate use of pesticides can produce numerous damages to the environment. Therefore, this review has the objective to provide an overview on the main characteristics of the herbicides based on 2,4-D, mostly on the role of microorganisms in its degradation and its main degradation metabolite, 2,4- dichlorophenol (2,4-DCP). The remediation processes carried out by microorganisms are advantageous to avoid the pollution of the environment as well as to safeguard the population health.
PMID: 32770339
J Plant Physiol , IF:3.013 , 2020 Aug , V253 : P153267 doi: 10.1016/j.jplph.2020.153267
Adventitious root formation is dynamically regulated by various hormones in leaf-vegetable sweetpotato cuttings.
Engineering Research Centre of Ecology and Agricultural Use of Wetland, Ministry of Education/ Hubei Collaborative Innovation Center for Grain Industry, Yangtze University, Jingzhou, 434025, China.; Engineering Research Centre of Ecology and Agricultural Use of Wetland, Ministry of Education/ Hubei Collaborative Innovation Center for Grain Industry, Yangtze University, Jingzhou, 434025, China; Hubei Key Laboratory of Food Crops Germplasm and Genetic Improvement, Institute of Food Corps/ Hubei Sweetpotato Engineering and Technology Research Centre, Hubei Academy of Agricultural Sciences, Wuhan, 430064, China.; College of Horticulture & Gardening, Yangtze University, Jingzhou, 434025, China.; Engineering Research Centre of Ecology and Agricultural Use of Wetland, Ministry of Education/ Hubei Collaborative Innovation Center for Grain Industry, Yangtze University, Jingzhou, 434025, China. Electronic address: wyzhang@yangtzeu.edu.cn.; Hubei Key Laboratory of Food Crops Germplasm and Genetic Improvement, Institute of Food Corps/ Hubei Sweetpotato Engineering and Technology Research Centre, Hubei Academy of Agricultural Sciences, Wuhan, 430064, China. Electronic address: yangxins013@163.com.
Leaf-vegetable sweetpotato is an important cash crop that is of high nutritional value. Cuttage is the most convenient method for large-scale propagation. However, the rate and number of adventitious roots (ARs) formation vary significantly among different cultivar cuttings. In this study, two varieties, NC1 and FC13-14, were used to compare the rate of ARs formation. The cumulative results of root morphology showed that in NC1 total root length, total root surface area, total root volume, and root tips were 3.7, 3.5, 3.2, and 2.4 times greater, respectively, than those of FC13-14 at 7 d, indicating that the ARs formation and growth were faster in NC1. In addition, the biomass of aboveground and underground parts in NC1 was 3.6 and 1.3 times more, respectively, than that of FC13-14 at 7 d after cutting, suggesting that the rapid ARs formation rate contributed to the growth and yield of stems and leaves. The analysis of plant water potential showed that NC1 exhibiting higher water potential prevented leaf wilting. Gene expression levels of 22 root-related genes revealed differential expression during different developmental periods. Interestingly, YUCCA family genes had elevated transcript abundance at 0, 12, 24, and 36 h. Moreover, analysis of hormones including indole-3-acetic acid (IAA), ethylene (ETH), abscisic acid (ABA), brassinolide (BR), jasmonic acid (JA), gibberellin (GA), and cytokinin (CTK) revealed varied contents during different developmental stages. Cumulative evidence demonstrated that gene expression profiles and hormone content of IAA, ETH, and BR were significantly higher in NC1 roots than in FC13-14 roots following all time periods, while the amount of JA increased and was higher in FC13-14 than in NC1 from 0 to 72 h. This indicates that IAA, BR, and ETH play positive roles and JA has a negative effect on ARs formation. Moreover, ETH takes effect earlier than BR, while IAA and JA have functions throughout the whole process. The findings above were validated by the application of exogenous hormones and hormone synthesis inhibitors. This study reveals the preliminary regulation of ARs formation in leaf-vegetable sweetpotato cuttings and thus contributes to further clarification of the molecular mechanism of multiple hormone interactions.
PMID: 32858442
Gene , IF:2.984 , 2020 Aug , V753 : P144803 doi: 10.1016/j.gene.2020.144803
Characterization of the soybean R2R3-MYB transcription factor GmMYB81 and its functional roles under abiotic stresses.
College of Plant Science, Jilin University, Changchun 130062, Jilin, China.; National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450001, Henan, China.; College of Plant Science, Jilin University, Changchun 130062, Jilin, China. Electronic address: xuyanli@jlu.edu.cn.
R2R3-type MYBs are a key group of regulatory factors that control diverse developmental processes and stress tolerance in plants. Soybean is a major legume crop with the richness of seed protein and edible vegetable oil, and 244 R2R3-type MYBs have been identified in soybean. However, the knowledge regarding their functional roles has been greatly limited as yet. In this study, a novel R2R3-type MYB (GmMYB81) was functionally characterized in soybean, and it is closely related to two abiotic stress-associated regulators (AtMYB44 and AtMYB77). GmMYB81 transcripts not only differentially accumulated in soybean tissues and during embryo development, but also were significantly enhanced by drought, salt and cold stress. Histochemical GUS assay in Arabidopsis indicated that GmMYB81 promoter showed high activity in seedlings, rosette leaves, inflorescences, silique wall, mature anthers, roots, and germinating seeds. Further investigation indicated that over-expression of GmMYB81 in Arabidopsis caused auxin-associated phenotypes, including small flower and silique, more branch, and weakened apical dominance. Moreover, over-expression of GmMYB81 significantly elevated the rates of seed germination and green seedling under salt and drought stress, indicating that GmMYB81 might confer plant tolerance to salt and drought stress during seed germination. Additionally, protein interaction analysis showed that GmMYB81 interacts with the abiotic stress regulator GmSGF14l. Further observation indicated that they displayed similar expression patterns under drought and salt stress, suggesting GmMYB81 and GmSGF14l might cooperatively affect stress tolerance. These findings will facilitate future investigations of the regulatory mechanisms of GmMYB81 in response to plant stress tolerance, especially seed germination under abiotic stresses.
PMID: 32446917
Gene , IF:2.984 , 2020 Aug , V750 : P144725 doi: 10.1016/j.gene.2020.144725
Identification and expression analysis of the small auxin-up RNA (SAUR) gene family in apple by inducing of auxin.
College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China.; College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China. Electronic address: bhch@gsau.edu.cn.
The small auxin-up RNA (SAUR) family plays a vital role in the regulation of plant growth and development. We identified 80 MdSAUR genes in this study. Phylogenetic analysis indicated that the SAUR proteins from Arabidopsis, rice, and apple were divided into six groups. Of the 80 MdSAURs, 71 were randomly distributed along the 17 chromosomes, while the remaining genes were located along unassigned scafoolds. Among them, a comprehensive overview of SAUR gene family is presented, including gene structures, chromosome locations, duplication and selection pressure analyses, synteny and promoter analyses, and protein interaction. The expression profiles based on microarray data found that 80 genes showed increased expression levels in at least one tissue including seed, seedling, root, stem, leaf, flower, fruit 100daa, and harvested fruit. MdSAUR7 possibly regulate the development of flower organs, and MdSAUR15, MdSAUR24, and MdSAUR80 promote the growth of fruits by regulating cell division. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated the expression levels of 79 MdSAUR genes in leaves under exogenous IAA treatment. MdSAUR4, MdSAUR22, MdSAUR37, MdSAUR38, MdSAUR49, and MdSAUR54 were up-regulated after IAA treatment compared with the control, indicating that they may play specific roles in the IAA signaling transduction pathway. This work provided a foundation for further investigations for the functional analyses of SAURs in apple.
PMID: 32360839
Plants (Basel) , IF:2.762 , 2020 Aug , V9 (9) doi: 10.3390/plants9091092
The Phylogeny of Class B Flavoprotein Monooxygenases and the Origin of the YUCCA Protein Family.
Institute of Cytology and Genetics, SB RAS, 630090 Novosibirsk, Russia.; Biosoft.ru, 630058 Novosibirsk, Russia.; Faculty of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia.; Kurchatov Genomics Center, Institute of Cytology and Genetics, SB RAS, 630090 Novosibirsk, Russia.
YUCCA (YUCCA flavin-dependent monooxygenase) is one of the two enzymes of the main auxin biosynthesis pathway (tryptophan aminotransferase enzyme (TAA)/YUCCA) in land plants. The evolutionary origin of the YUCCA family is currently controversial: YUCCAs are assumed to have emerged via a horizontal gene transfer (HGT) from bacteria to the most recent common ancestor (MRCA) of land plants or to have inherited it from their ancestor, the charophyte algae. To refine YUCCA origin, we performed a phylogenetic analysis of the class B flavoprotein monooxygenases and comparative analysis of the sequences belonging to different families of this protein class. We distinguished a new protein family, named type IIb flavin-containing monooxygenases (FMOs), which comprises homologs of YUCCA from Rhodophyta, Chlorophyta, and Charophyta, land plant proteins, and FMO-E, -F, and -G of the bacterium Rhodococcus jostii RHA1. The type IIb FMOs differ considerably in the sites and domain composition from the other families of class B flavoprotein monooxygenases, YUCCAs included. The phylogenetic analysis also demonstrated that the type IIb FMO clade is not a sibling clade of YUCCAs. We have also identified the bacterial protein group named YUC-like FMOs as the closest to YUCCA homologs. Our results support the hypothesis of the emergence of YUCCA via HGT from bacteria to MRCA of land plants.
PMID: 32854417
Plants (Basel) , IF:2.762 , 2020 Aug , V9 (9) doi: 10.3390/plants9091061
Genome-Wide Analysis of the PIN Auxin Efflux Carrier Gene Family in Coffee.
Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.; Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Haikou 571101, China.; Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou 571101, China.; Dehong Tropical Agriculture Research Institute of Yunnan, Ruili 678600, China.; School of Life Sciences, Peking University, Beijing 100871, China.; Plant Biotechnology Unit, Department of Biotechnology, BOKU-VIBT, University of Natural Resources and Life Sciences, Vienna 1190, Austria.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.; College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.; Coffee Engineering Research Center of China, Mangshi 678400, China.
Coffee is one of the most popular beverages around the world, which is mainly produced from the allopolyploid Coffea arabica. The genomes of C. arabica and its two ancestors C. canephora and C. eugenioides have been released due to the development of next generation sequencing. However, few studies on C. arabica are related to the PIN-FORMED (PIN) auxin efflux transporter despite its importance in auxin-mediated plant growth and development. In the present study, we conducted a genome-wide analysis of the PIN gene family in the three coffee species. Totals of 17, 9 and 10 of the PIN members were characterized in C. Arabica, C. canephora and C. eugenioides, respectively. Phylogenetic analysis revealed gene loss of PIN1 and PIN2 homologs in C. arabica, as well as gene duplication of PIN5 homologs during the fractionation process after tetraploidy. Furthermore, we conducted expression analysis of PIN genes in C. arabica by in silico and qRT-PCR. The results revealed the existence of gene expression dominance in allopolyploid coffee and illustrated several PIN candidates in regulating auxin transport and homeostasis under leaf rust fungus inoculation and the tissue-specific expression pattern of C. arabica. Together, this study provides the basis and guideline for future functional characterization of the PIN gene family.
PMID: 32825074
Plants (Basel) , IF:2.762 , 2020 Aug , V9 (9) doi: 10.3390/plants9091059
Gaining Insight into Exclusive and Common Transcriptomic Features Linked to Drought and Salinity Responses across Fruit Tree Crops.
Department of Agricultural, Food and Forest Sciences, University of Palermo, Viale delle Scienze-Ed. 4, 90128 Palermo, Italy.; Council for Agricultural Research and Economics (CREA), Research Centre for Plant Protection and Certification (CREA-DC), 90011 Bagheria, Italy.; Department of Architecture (DARCH), University of Palermo, Viale delle Scienze-Ed. 8, 90128 Palermo, Italy.; Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, 90128 Palermo, Italy.; Department of Biology, University of Florence, Sesto Fiorentino, 50019 Florence, Italy.
The present study aimed at identifying and mapping key genes expressed in root tissues involved in drought and salinity tolerance/resistance conserved among different fruit tree species. Twenty-six RNA-Seq samples were analyzed from six published studies in five plant species (Olea europaea, Vitis riparia Michx, Prunus mahaleb, Prunus persica, Phoenix dactylifera). This meta-analysis used a bioinformatic pipeline identifying 750 genes that were commonly modulated in three salinity studies and 683 genes that were commonly regulated among three drought studies, implying their conserved role in resistance/tolerance/response to these environmental stresses. A comparison was done on the genes that were in common among both salinity and drought resulted in 82 genes, of which 39 were commonly regulated with the same trend of expression (23 were upregulated and 16 were downregulated). Gene set enrichment and pathway analysis pointed out that pathways encoding regulation of defense response, drug transmembrane transport, and metal ion binding are general key molecular responses to these two abiotic stress responses. Furthermore, hormonal molecular crosstalk plays an essential role in the fine-tuning of plant responses to drought and salinity. Drought and salinity induced a different molecular "hormonal fingerprint". Dehydration stress specifically enhanced multiple genes responsive to abscisic acid, gibberellin, brassinosteroids, and the ethylene-activated signaling pathway. Salt stress mostly repressed genes encoding for key enzymes in signaling proteins in auxin-, gibberellin-(gibberellin 2 oxidase 8), and abscisic acid-related pathways (aldehyde oxidase 4, abscisic acid-responsive element-binding protein 3). Abiotic stress-related genes were mapped into the chromosome to identify molecular markers usable for the improvement of these complex quantitative traits. This meta-analysis identified genes that serve as potential targets to develop cultivars with enhanced drought and salinity resistance and/or tolerance across different fruit tree crops in a biotechnological sustainable way.
PMID: 32825043
Plants (Basel) , IF:2.762 , 2020 Aug , V9 (8) doi: 10.3390/plants9081037
Molecular Mechanisms Supporting Rice Germination and Coleoptile Elongation under Low Oxygen.
PlantLab, Institute of Life Sciences, Scuola Superiore Sant'Anna, 56124 Pisa, Italy.
Rice germinates under submergence by exploiting the starch available in the endosperm and translocating sugars from source to sink organs. The availability of fermentable sugar under water allows germination with the protrusion of the coleoptile, which elongates rapidly and functions as a snorkel toward the air above. Depending on the variety, rice can produce a short or a long coleoptile. Longer length entails the involvement of a functional transport of auxin along the coleoptile. This paper is an overview of rice coleoptiles and the studies undertaken to understand its functioning and role under submergence.
PMID: 32824201
Plants (Basel) , IF:2.762 , 2020 Aug , V9 (8) doi: 10.3390/plants9081030
In Vitro Responses of Plant Growth Factors on Growth, Yield, Phenolics Content and Antioxidant Activities of Clinacanthus nutans (Sabah Snake Grass).
Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, UPM, Serdang 43400, Selangor, Malaysia.
Clinacanthus nutans, commonly known as Sabah snake grass, is one of the more important medicinal plants in Malaysia's herbal industry. C. nutans has gained the attention of medical practitioners due to its wide range of bioactive compounds responsible for various biological activities, such as anti-cancer, anti-venom and anti-viral activities. Due to its high pharmacological properties, the species has been overexploited to meet the demands of the pharmaceutical industry. The present study was conducted to establish a suitable in vitro culture procedure for the mass propagation of C. nutans. Murashige and Skoog (MS) basal medium, supplemented with different types of cytokinins, auxins, basal medium strength and sucrose concentrations, were tested. Based on the results, a full-strength MS basal medium supplemented with 12 microM 6-benzylaminopurine (BAP) and 30 g/L sucrose was recorded as the best outcome for all the parameters measured including the regeneration percentage, number of shoots, length of shoots, number of leaves and fresh weight of leaves. In the analysis of the phenolics content and antioxidant activities, tissue-cultured leaf extracts assayed at 100 degrees C exhibited the highest phenolic content and antioxidant activities. The propagation of C. nutans via a plant tissue culture technique was recorded to be able to produce high phenolic contents as well as exhibit high antioxidant activities.
PMID: 32823824
PLoS One , IF:2.74 , 2020 , V15 (8) : Pe0235962 doi: 10.1371/journal.pone.0235962
Comparative transcriptome analysis provides insights into the molecular mechanism underlying double fertilization between self-crossed Solanum melongena and that hybridized with Solanum aethiopicum.
College of Horticulture, South China Agricultural University, Guangzhou, China.; Institute of Vegetable Research, Guangxi Academy of Agricultural Sciences, Nanning, China.; Guangxi Key Laboratory of Vegetable Breeding and New Technology Development, Nanning, China.
Wild relatives represent a source of variation for many traits of interest for eggplant (Solanum melongena) breeding, as well as for broadening its genetic base. However, interspecific hybridization with wild relatives has been barely used in eggplant breeding programs, and reproductive barriers have resulted in reduced seed numbers in interspecific combinations. The mechanism underlying this phenomenon remains unclear. We hybridized females of cultivated eggplant 177 (Solanum melongena) with males of wild relatives 53 and Y11 (Solanum aethiopicum). Self-crossed 177 was the control. The seed number per control fruit was significantly higher than that of the hybrids. Paraffin sections showed no significant difference between control and 177x53 and 177xY11. Double fertilization began 4 days post-pollination. Sperm cells were fused with egg cells 6 days post-pollination. To understand the differences in molecular mechanisms underlying this process, transcriptomes of ovaries at 0, 4, and 6 days after self-crossing and hybridization were analyzed. We screened 22,311 differentially expressed genes (DEGs) between the control and hybrids 4 and 6 days post-pollination. A total of 497 DEGs were shared among all pollination combinations. These DEGs were enriched in plant hormone transduction, cell senescence, metabolism, and biosynthesis pathways. DEG clustering analysis indicated distinct expression patterns between the control and hybrids but not between the hybrids. The DEGs in hybrids involved secondary metabolic process, phenylpropanoid metabolic process, and carboxypeptidase activity, while those in the control involved xyloglucan metabolic process, auxin-activated signaling pathway, cell wall polysaccharide metabolic process, and xyloglucosyl transferase activity. Additionally, 1683 transcription factors, including members of the AP2-ERF, MYB, bHLH, and B3 families may play important roles in self-crossing and hybridization. Our results provide insights into the regulatory mechanisms underlying variations between ovaries of self-crossed and hybrid eggplants and a basis for future studies on crossbreeding Solanum and genetic mechanisms underlying double fertilization.
PMID: 32760091
Biol Open , IF:2.029 , 2020 Aug 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 crystallinum, 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
Plant Signal Behav , IF:1.671 , 2020 Aug : P1809847 doi: 10.1080/15592324.2020.1809847
Indeterminate domain 3 negatively regulates plant erectness and the resistance of rice to sheath blight by controlling PIN-FORMED gene expressions.
College of Plant Protection, Shenyang Agricultural University , Shenyang, China.; School of Life Science and Technology, Hubei Engineering University , Xiaogan, China.; Citrus Research Institute, Southwest University , Chongqing, China.
Plant architecture and disease resistance are the key factors that control the production of yield. However, the mechanism behind these factors is largely unknown. In this study, we identified that indeterminate domain 3 (IDD3) was obviously induced by inoculation of Rhizoctonia solani AG1-IA. Plants that overexpressed IDD3 (IDD3 OX) were more susceptible, while idd3 mutants showed a similar response to sheath blight disease compared with wild-type plants. Interestingly, IDD3 OX plants developed a wider tiller angle and exhibited altered shoot gravitropism, while idd3 knock-out mutants showed no visible morphological differences compared with the wild-type plants. IDD3 is ubiquitously expressed in different tissues and stages, and the IDD3 transcript was induced by exogenously applied auxin. Expression of the PIN-FORMED (PIN) and Aux/IAA genes was altered in IDD3 OX compared with wild-type plants. Furthermore, IDD3 OX plants are sensitive to auxin and the polar auxin transporter inhibitor N-1-naphthylphalamic acid (NPA). Further yeast-one hybrid, chromatin immunoprecipitation (ChIP) and transient assays revealed that IDD3 directly represses PIN1b via promoter binding. Inoculation with R. solani indicated that PIN1b RNAi plants are more susceptible to sheath blight disease (ShB) compared with the wild-type. Taken together, our analyses suggest that IDD3 controls plant architecture and the resistance of rice to ShB via the regulation of PIN auxin transporter genes.
PMID: 32842845
Plant Signal Behav , IF:1.671 , 2020 Aug : P1805232 doi: 10.1080/15592324.2020.1805232
Strigolactone elevates ethylene biosynthesis in etiolated Arabidopsis seedlings.
Department of Botany and Plant Pathology and Center for Plant Biology, Purdue University , West Lafayette, IN, USA.
The gaseous phytohormone ethylene influences many aspects of plant life, including germination, fruit ripening, senescence, and stress responses. These diverse roles of ethylene occur in part through crosstalk with other phytohormones, which affects ethylene biosynthesis and signaling pathways. We have recently shown that the phytohormones, including gibberellic acid, abscisic acid, auxin, methyl jasmonate, and salicylic acid, regulate the stability of ACC synthases (ACSs), the rate-limiting enzymes in ethylene biosynthesis. Here, we report that treatment of etiolated Arabidopsis seedlings with strigolactone (SL) increases ethylene biosynthesis. SL does not influence ACS stability or ACS gene expression, but it increases the transcript levels of a subset of ACC oxidase (ACO) genes, thereby enhancing ethylene biosynthesis. Taken together with the results of our previous study, these findings demonstrate that most phytohormones differentially regulate ethylene biosynthesis in dark-grown Arabidopsis seedlings by affecting ACS stability and/or the transcript levels of ethylene biosynthesis genes.
PMID: 32835599
Plant Signal Behav , IF:1.671 , 2020 Aug , V15 (8) : P1777377 doi: 10.1080/15592324.2020.1777377
Glycosyltransferase UGT76F1 is involved in the temperature-mediated petiole elongation and the BR-mediated hypocotyl growth in Arabidopsis.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education; School of Life Sciences, Shandong University , Qingdao, PR. China.
The signaling network formed by external environmental signals and endogenous hormone signals is an important basis for the adaptive growth of plants. We recently identified a UDP-glucosyltransferase gene, UGT76F1, which controls the glucosylation of auxin precursor IPyA and mediates light-temperature signaling to regulate auxin-dependent hypocotyl elongation in Arabidopsis. However, it is unclear whether UGT76F1 is involved in the adaptive growth of other tissues and whether it is related to the signaling of other hormones besides auxin. Here we investigated the petiole elongation of UGT76F1 overexpression lines and knockout mutant lines, and also studied the effects of UGT76F1 on BR signaling. Experimental results indicated that UGT76F1 is involved in the PIF4-mediated petiole growth under high temperature and that UGT76F1 is also related to the BR signaling in controlling hypocotyl growth. These results suggest that UGT76F1 may have a wider significance in the plant adaptations to surrounding environments.
PMID: 32491966
Microbiol Resour Announc , 2020 Aug , V9 (33) doi: 10.1128/MRA.00768-20
Draft Genome Sequences of Pseudomonas koreensis Strain UASWS1668, Bacillus megaterium Strain UASWS1667, and Paenibacillus sp. Strain UASWS1643, Considered Potential Plant Growth-Promoting Rhizobacteria.
Plants and Pathogens Group, Research Institute Land Nature and Environment, Geneva School of Engineering, Landscape and Architecture (HEPIA), HES-SO University of Applied Sciences and Arts Western Switzerland, Jussy, Geneva, Switzerland.; Plants and Pathogens Group, Research Institute Land Nature and Environment, Geneva School of Engineering, Landscape and Architecture (HEPIA), HES-SO University of Applied Sciences and Arts Western Switzerland, Jussy, Geneva, Switzerland francois.lefort@hesge.ch.
Plant growth-promoting rhizobacteria (PGPR) include species in the genera Bacillus, Paenibacillus, and Pseudomonas We report here the draft genome sequences of the strains Pseudomonas koreensis UASWS1668 and Bacillus megaterium UASWS1667, isolated from a horse chestnut tree, and Paenibacillus sp. strain UASWS1643, isolated from a tomato stem. Auxin production and phosphate solubilization were biochemically confirmed.
PMID: 32817155