Mol Plant , IF:13.164 , 2021 Aug doi: 10.1016/j.molp.2021.08.011
The BZR1-EDS1 module regulates plant growth-defense coordination.
State Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, and Center for Crop Genome Engineering, Henan Agricultural University, Zhengzhou 450002, China; Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.; Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA; Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.; College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China.; State Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, and Center for Crop Genome Engineering, Henan Agricultural University, Zhengzhou 450002, China.; Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266109, China.; Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, 266237 Qingdao, China.; Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.; State Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, and Center for Crop Genome Engineering, Henan Agricultural University, Zhengzhou 450002, China. Electronic address: dwwang@henau.edu.cn.; Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA. Electronic address: dwwang@henau.edu.cn.
Plants have developed sophisticated strategies to coordinate growth and immunity, but our understanding of the underlying mechanism remains limited. Here we identified a novel molecular module that regulates plant growth and defense in both compatible and incompatible infections. This module consisted of BZR1, a key transcription factor in brassinosteroid (BR) signaling, and EDS1, an essential positive regulator of plant innate immunity. EDS1 interacted with BZR1 and suppressed its transcriptional activities. Consistently, upregulation of EDS1 function by virulent Pseudomonas syringae strain or salicylic acid treatment inhibited BZR1-regulated expression of BR-responsive genes and BR-promoted growth. Furthermore, we showed that the cytoplasmic fraction of BZR1 positively regulated effector-triggered immunity (ETI) controlled by the TIR-NB-LRR protein RPS4, which was attenuated by BZR1's nuclear translocation. Mechanistically, cytoplasmic BZR1 facilitated AvrRps4-triggered dissociation between EDS1 and RPS4 by binding to EDS1, thus leading to efficient activation of RPS4-controlled ETI. Notably, transgenic expression of a mutant BZR1 that accumulated exclusively in the cytoplasm improved pathogen resistance without compromising plant growth. Our results shed new light on plant growth-defense coordination, and reveal a previously unknown function for the cytoplasmic fraction of BZR1. The BZR1-EDS1 module may be harnessed for simultaneously improving crop productivity and pathogen resistance.
PMID: 34416351
Mol Plant , IF:13.164 , 2021 Aug doi: 10.1016/j.molp.2021.07.021
A single-cell morpho-transcriptomic map of brassinosteroid action in the Arabidopsis root.
Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland.; Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9000 Ghent, Belgium; VIB Center for Plant Systems Biology, Technologiepark 71, 9000 Ghent, Belgium.; Bioinformatics Competence Center, University of Lausanne, Genopode Building, 1015 Lausanne, Switzerland.; School of Life Sciences, The University of Warwick, Coventry, CV4 7AL, UK.; Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland. Electronic address: christian.hardtke@unil.ch.
The effects of brassinosteroid signaling on shoot and root development have been characterized in great detail but a simple consistent positive or negative impact on a basic cellular parameter was not identified. In this study, we combined digital 3D single-cell shape analysis and single-cell mRNA sequencing to characterize root meristems and mature root segments of brassinosteroid-blind mutants and wild type. The resultant datasets demonstrate that brassinosteroid signaling affects neither cell volume nor cell proliferation capacity. Instead, brassinosteroid signaling is essential for the precise orientation of cell division planes and the extent and timing of anisotropic cell expansion. Moreover, we found that the cell-aligning effects of brassinosteroid signaling can propagate to normalize the anatomy of both adjacent and distant brassinosteroid-blind cells through non-cell-autonomous functions, which are sufficient to restore growth vigor. Finally, single-cell transcriptome data discern directly brassinosteroid-responsive genes from genes that can react non-cell-autonomously and highlight arabinogalactans as sentinels of brassinosteroid-dependent anisotropic cell expansion.
PMID: 34358681
Mol Plant , IF:13.164 , 2021 Aug , V14 (8) : P1379-1390 doi: 10.1016/j.molp.2021.05.006
Chemical control of receptor kinase signaling by rapamycin-induced dimerization.
Department of Life Sciences, Korea University, Seoul, Korea.; Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, Korea; Kumho Life Science Laboratory, Chonnam National University, Gwangju, Korea.; Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, Korea.; Department of Life Sciences, Korea University, Seoul, Korea. Electronic address: ekoh@korea.ac.kr.; Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, Korea; Kumho Life Science Laboratory, Chonnam National University, Gwangju, Korea; Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju, Korea. Electronic address: jungmkim@jnu.ac.kr.
Membrane-localized leucine-rich repeat receptor kinases (LRR-RKs) sense diverse extracellular signals, and coordinate and specify cellular functions in plants. However, functional understanding and identification of the cellular signaling of most LRR-RKs remain a major challenge owing to their genetic redundancy, the lack of ligand information, and subtle phenotypes of LRR-RK overexpression. Here, we report an engineered rapamycin-inducible dimerization (RiD) receptor system that triggers a receptor-specific LRR-RK signaling independent of their cognate ligands or endogenous receptors. Using the RiD-receptors, we demonstrated that the rapamycin-mediated association of chimeric cytosolic kinase domains from the BRI1/BAK1 receptor/co-receptor, but not the BRI1/BRI1 or BAK1/BAK1 homodimer, is sufficient to activate downstream brassinosteroid signaling and physiological responses. Furthermore, we showed that the engineered RiD-FLS2/BAK1 could activate flagellin-22-mediated immune signaling and responses. Using the RiD system, we also identified the potential function of an unknown orphan receptor in immune signaling and revealed the differential activities of SERK co-receptors of LRR-RKs. Our results indicate that the RiD method can serve as a synthetic biology tool for precise temporal manipulation of LRR-RK signaling and for understanding LRR-RK biology.
PMID: 33964457
Plant Cell , IF:11.277 , 2021 Aug doi: 10.1093/plcell/koab210
The F-box E3 ubiquitin ligase BAF1 mediates the degradation of the brassinosteroid-activated transcription factor BES1 through selective autophagy in Arabidopsis.
Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA.; Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA.; Plant Sciences Institutes, Iowa State University, Ames, IA 50011, USA.
Brassinosteroids (BRs) regulate plant growth, development and stress responses by activating the core transcription factor BRI1-EMS-SUPPRESSOR1 (BES1), whose degradation occurs through the proteasome and autophagy pathways. The E3 ubiquitin ligase(s) that modify BES1 for autophagy-mediated degradation remain to be fully defined. Here, we identified an F-box family E3 ubiquitin ligase named BES1-ASSOCIATED F-BOX1 (BAF1) in Arabidopsis thaliana. BAF1 interacts with BES1 and mediates its ubiquitination and degradation. Our genetic data demonstrated that BAF1 inhibits BR signaling in a BES1-dependent manner. Moreover, BAF1 targets BES1 for autophagic degradation in a selective manner. BAF1-triggered selective autophagy of BES1 depends on the ubiquitin binding receptor DOMINANT SUPPRESSOR OF KAR2 (DSK2). Sucrose starvation-induced selective autophagy of BES1, but not bulk autophagy, was significantly compromised in baf1 mutant and BAF1-DeltaF (BAF1 F-box decoy) overexpression plants, but clearly increased by BAF1 overexpression. The baf1 and BAF1-DeltaF overexpression plants had increased BR-regulated growth but were sensitive to long-term sucrose starvation, while BAF1 overexpression plants had decreased BR-regulated growth but were highly tolerant of sucrose starvation. Our results not only established BAF1 as an E3 ubiquitin ligase that targets BES1 for degradation through selective autophagy pathway, but also revealed a mechanism for plants to reduce growth during sucrose starvation.
PMID: 34436598
Plant Cell , IF:11.277 , 2021 Aug , V33 (7) : P2360-2374 doi: 10.1093/plcell/koab112
Arabidopsis NF-YCs play dual roles in repressing brassinosteroid biosynthesis and signaling during light-regulated hypocotyl elongation.
Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Innovative Academy of Seed Design, Chinese Academy of Sciences, Guangzhou, China.; University of the Chinese Academy of Sciences, Beijing, China.; School of Life Sciences, Guangzhou University, Guangzhou, China.
Light functions as the primary environmental stimulus and brassinosteroids (BRs) as important endogenous growth regulators throughout the plant lifecycle. Photomorphogenesis involves a series of vital developmental processes that require the suppression of BR-mediated seedling growth, but the mechanism underlying the light-controlled regulation of the BR pathway remains unclear. Here, we reveal that nuclear factor YC proteins (NF-YCs) function as essential repressors of the BR pathway during light-controlled hypocotyl growth in Arabidopsis thaliana. In the light, NF-YCs inhibit BR biosynthesis by directly targeting the promoter of the BR biosynthesis gene BR6ox2 and repressing its transcription. NF-YCs also interact with BIN2, a critical repressor of BR signaling, and facilitate its stabilization by promoting its Tyr200 autophosphorylation, thus inhibiting the BR signaling pathway. Consistently, loss-of-function mutants of NF-YCs show etiolated growth and constitutive BR responses, even in the light. Our findings uncover a dual role of NF-YCs in repressing BR biosynthesis and signaling, providing mechanistic insights into how light antagonizes the BR pathway to ensure photomorphogenic growth in Arabidopsis.
PMID: 33871651
Proc Natl Acad Sci U S A , IF:11.205 , 2021 Aug , V118 (34) doi: 10.1073/pnas.2011900118
Reciprocal antagonistic regulation of E3 ligases controls ACC synthase stability and responses to stress.
Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47906.; The Center for Plant Biology, Purdue University, West Lafayette, IN 47906.; Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47906; yoong@purdue.edu.
Ethylene influences plant growth, development, and stress responses via crosstalk with other phytohormones; however, the underlying molecular mechanisms are still unclear. Here, we describe a mechanistic link between the brassinosteroid (BR) and ethylene biosynthesis, which regulates cellular protein homeostasis and stress responses. We demonstrate that as a scaffold, 1-aminocyclopropane-1-carboxylic acid (ACC) synthases (ACS), a rate-limiting enzyme in ethylene biosynthesis, promote the interaction between Seven-in-Absentia of Arabidopsis (SINAT), a RING-domain containing E3 ligase involved in stress response, and ETHYLENE OVERPRODUCER 1 (ETO1) and ETO1-like (EOL) proteins, the E3 ligase adaptors that target a subset of ACS isoforms. Each E3 ligase promotes the degradation of the other, and this reciprocally antagonistic interaction affects the protein stability of ACS. Furthermore, 14-3-3, a phosphoprotein-binding protein, interacts with SINAT in a BR-dependent manner, thus activating reciprocal degradation. Disrupted reciprocal degradation between the E3 ligases compromises the survival of plants in carbon-deficient conditions. Our study reveals a mechanism by which plants respond to stress by modulating the homeostasis of ACS and its cognate E3 ligases.
PMID: 34404725
Proc Natl Acad Sci U S A , IF:11.205 , 2021 Aug , V118 (33) doi: 10.1073/pnas.2101838118
Nucleocytoplasmic trafficking and turnover mechanisms of BRASSINAZOLE RESISTANT1 in Arabidopsis thaliana.
Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, 050024 Shijiazhuang, China.; Department of Bioscience and Bioengineering, Hebei University of Science and Technology, 050000 Shijiazhuang, China.; Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, 050024 Shijiazhuang, China; tangwq@mail.hebtu.edu.cn.
Regulation of the nucleocytoplasmic trafficking of signaling components, especially transcription factors, is a key step of signal transduction in response to extracellular stimuli. In the brassinosteroid (BR) signal transduction pathway, transcription factors from the BRASSINAZOLE RESISTANT1 (BZR1) family are essential in mediating BR-regulated gene expression. The subcellular localization and transcriptional activity of BZR1 are tightly regulated by reversible protein phosphorylation; however, the underlying mechanism is not well understood. Here, we provide evidence that both BZR1 phosphorylation and dephosphorylation occur in the nucleus and that BR-regulated nuclear localization of BZR1 is independent from its interaction with, or dephosphorylation by, protein phosphatase 2A. Using a photoconvertible fluorescent protein, Kaede, as a living tag to distinguish newly synthesized BZR1 from existing BZR1, we demonstrated that BR treatment recruits cytosolic BZR1 to the nucleus, which could explain the fast responses of plants to BR. Additionally, we obtained evidence for two types of protein turnover mechanisms that regulate BZR1 abundance in plant cells: a BR- and 26S proteosome-independent constitutive degradation mechanism and a BR-activated 26S proteosome-dependent proteolytic mechanism. Finally, treating plant cells with inhibitors of 26S proteosome induces the nuclear localization and dephosphorylation of BZR1, even in the absence of BR signaling. Based on these results, we propose a model to explain how BR signaling regulates the nucleocytoplasmic trafficking and reversible phosphorylation of BZR1.
PMID: 34385302
Curr Biol , IF:10.834 , 2021 Aug doi: 10.1016/j.cub.2021.07.075
Auxin requirements for a meristematic state in roots depend on a dual brassinosteroid function.
Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel.; Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel.; Lorey I. Lokey Interdisciplinary Center for Life Sciences and Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel.; Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Olomouc, Czech Republic.; Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel. Electronic address: sigal@technion.ac.il.
Root meristem organization is maintained by an interplay between hormone signaling pathways that both interpret and determine their accumulation and distribution. The interacting hormones Brassinosteroids (BR) and auxin control the number of meristematic cells in the Arabidopsis root. BR was reported both to promote auxin signaling input and to repress auxin signaling output. Whether these contradicting molecular outcomes co-occur and what their significance in meristem function is remain unclear. Here, we established a dual effect of BR on auxin, with BR simultaneously promoting auxin biosynthesis and repressing auxin transcriptional output, which is essential for meristem maintenance. Blocking BR-induced auxin synthesis resulted in rapid BR-mediated meristem loss. Conversely, plants with reduced BR levels were resistant to a critical loss of auxin biosynthesis, maintaining their meristem morphology. In agreement, injured root meristems, which rely solely on local auxin synthesis, regenerated when both auxin and BR synthesis were inhibited. Use of BIN2 as a tool to selectively inhibit BR signaling yielded meristems with distinct phenotypes depending on the perturbed tissue: meristem reminiscent either of BR-deficient mutants or of high BR exposure. This enabled mapping of the BR-auxin interaction that maintains the meristem to the outer epidermis and lateral root cap tissues and demonstrated the essentiality of BR signaling in these tissues for meristem response to BR. BR activity in internal tissues however, proved necessary to control BR levels. Together, we demonstrate a basis for inter-tissue coordination and how a critical ratio between these hormones determines the meristematic state.
PMID: 34418341
Plant Biotechnol J , IF:9.803 , 2021 Aug doi: 10.1111/pbi.13677
Separable regulation of POW1 in grain size and leaf angle development in rice.
State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China.; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China.; College of Life Science, Henan Agricultural University, Zhengzhou, China.
Leaf angle is one of the key factors that determines rice plant architecture. However, the improvement of leaf angle erectness is often accompanied by unfavourable changes in other traits, especially grain size reduction. In this study, we identified the pow1 (put on weight 1) mutant that leads to increased grain size and leaf angle, typical brassinosteroid (BR)-related phenotypes caused by excessive cell proliferation and cell expansion. We show that modulation of the BR biosynthesis genes OsDWARF4 (D4) and D11 and the BR signalling gene D61 could rescue the phenotype of leaf angle but not grain size in the pow1 mutant. We further demonstrated that POW1 functions in grain size regulation by repressing the transactivation activity of the interacting protein TAF2, a highly conserved member of the TFIID transcription initiation complex. Down-regulation of TAF2 rescued the enlarged grain size of pow1 but had little effect on the increased leaf angle phenotype of the mutant. The separable functions of the POW1-TAF2 and POW1-BR modules in grain size and leaf angle control provide a promising strategy for designing varieties with compact plant architecture and increased grain size, thus promoting high-yield breeding in rice.
PMID: 34343399
J Exp Bot , IF:6.992 , 2021 Aug doi: 10.1093/jxb/erab365
Small molecule inhibitors of mammalian GSK-3beta promote in vitro plant cell reprogramming and somatic embryogenesis in crop and forest species.
Pollen Biotechnology of Crop Plants group, Center of Biological Research Margarita Salas, CIB-CSIC, Ramiro de Maeztu, Madrid, Spain.; Translational Medicinal and Biological Chemistry group, Center of Biological Research Margarita Salas, CIB-CSIC, Ramiro de Maeztu, Madrid, Spain.
Plant in vitro regeneration systems, like somatic embryogenesis, are essential in breeding; they permit to propagate elite genotypes, to produce doubled-haploids, and to convert gene editing or transformation events into plants. However, in many crop and forest species somatic embryogenesis is highly inefficient. We report a new strategy to improve in vitro embryogenesis using synthetic small molecule inhibitors of mammalian glycogen synthase kinase 3beta (GSK-3beta), never used in plants. These inhibitors increased in vitro embryo production in three different systems and species, microspore embryogenesis of Brassica napus and Hordeum vulgare, and somatic embryogenesis of Quercus suber. TDZD-8, representative compound of the molecules tested, inhibited GSK-3 activity in microspore cultures, and increased expression of embryogenesis- genes FUS3, LEC2 and AGL15. Plant GSK-3 kinase BIN2 is master regulator of brassinosteroid (BR) signalling. During microspore embryogenesis, BR biosynthesis and signalling genes CPD, GSK-3-BIN2, BES1 and BZR1 were upregulated and BAS1 catabolic gene was repressed, indicating activation of BR pathway. TDZD-8 increased expression of BR signalling elements, mimicking BR effects. The findings support that the small molecule inhibitors promoted somatic embryogenesis by activating the BR pathway, opening the way for new strategies using GSK-3beta inhibitors that could be extended to other species.
PMID: 34338766
Plant J , IF:6.417 , 2021 Aug doi: 10.1111/tpj.15425
Phytophthora infection signals-induced translocation of NAC089 is required for endoplasmic reticulum stress response-mediated plant immunity.
The Key Laboratory of Plant Immunity, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
Plants deploy various immune receptors to recognize pathogen-derived extracellular signals and subsequently activate the downstream defense response. Recently, increasing evidence indicates that the endoplasmic reticulum (ER) plays a part in the plant defense response, known as ER stress-mediated immunity (ERSI), that halts pathogen infection. However, the mechanism for the ER stress response to signals of pathogen infection remains unclear. Here, we characterized the ER stress response regulator NAC089, which was previously reported to positively regulate programed cell death (PCD), functioning as an ERSI regulator. NAC089 translocated from the ER to the nucleus via the Golgi in response to Phytophthora capsici culture filtrate (CF), which is a mixture of pathogen-associated molecular patterns (PAMPs). Plasma membrane localized co-receptor BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1 (BAK1) was required for the CF-mediated translocation of NAC089. The nuclear localization of NAC089, determined by the NAC domain, was essential for immune activation and PCD. Furthermore, NAC089 positively contributed to host resistance against the oomycete pathogen P. capsici and the bacteria pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. We also proved that NAC089-mediated immunity is conserved in Nicotiana benthamiana. Together, we found that PAMP signaling induces the activation of ER stress in plants, and that NAC089 is required for ERSI and plant resistance against pathogens.
PMID: 34374485
Int J Mol Sci , IF:5.923 , 2021 Aug , V22 (16) doi: 10.3390/ijms22168743
Genome-Wide Identification and Characterization of the Brassinazole-resistant (BZR) Gene Family and Its Expression in the Various Developmental Stage and Stress Conditions in Wheat (Triticum aestivum L.).
Institute for Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 08826, Korea.; Faculty of Agriculture, Sri Sri University, Cuttack 754-006, India.; Krishi Vigyan Kendra, Bikaner II, Swami Keshwanand Rajasthan Agricultural University, Bikaner 334603, India.; Department of Biotechnology, Centurion University of Technology and Management, Bhubaneshwar 752050, India.; Department of Dairy Microbiology, College of Dairy Science and Food Technology, Raipur 49200, India.; Department of Agriculture and Fisheries, Mareeba, QLD 4880, Australia.; Department of Medical Biotechnology, Biomedical Campus, Dongguk University, Seoul 10326, Korea.; Department of Botany, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi 110062, India.; Research Institute of Biotechnology and Medical Converged Science, Dongguk University-Seoul, 32 Dongguk-ro, Ilsandong-gu, Goyang 10326, Korea.; Department of Bioindustry and Bioresource Engineering, Plant Engineering Research Institute, Sejong University, Seoul 05006, Korea.; Department of Life Science, College of Life Science and Biotechnology, Dongguk University, Goyang 10326, Korea.
Brassinosteroids (BRs) play crucial roles in various biological processes, including plant developmental processes and response to diverse biotic and abiotic stresses. However, no information is currently available about this gene family in wheat (Triticum aestivum L.). In the present investigation, we identified the BZR gene family in wheat to understand the evolution and their role in diverse developmental processes and under different stress conditions. In this study, we performed the genome-wide analysis of the BZR gene family in the bread wheat and identified 20 TaBZR genes through a homology search and further characterized them to understand their structure, function, and distribution across various tissues. Phylogenetic analyses lead to the classification of TaBZR genes into five different groups or subfamilies, providing evidence of evolutionary relationship with Arabidopsis thaliana, Zea mays, Glycine max, and Oryza sativa. A gene exon/intron structure analysis showed a distinct evolutionary path and predicted the possible gene duplication events. Further, the physical and biochemical properties, conserved motifs, chromosomal, subcellular localization, and cis-acting regulatory elements were also examined using various computational approaches. In addition, an analysis of public RNA-seq data also shows that TaBZR genes may be involved in diverse developmental processes and stress tolerance mechanisms. Moreover, qRT-PCR results also showed similar expression with slight variation. Collectively, these results suggest that TaBZR genes might play an important role in plant developmental processes and various stress conditions. Therefore, this work provides valuable information for further elucidate the precise role of BZR family members in wheat.
PMID: 34445448
Int J Mol Sci , IF:5.923 , 2021 Aug , V22 (16) doi: 10.3390/ijms22168568
Function and Mechanism of Jasmonic Acid in Plant Responses to Abiotic and Biotic Stresses.
College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.
As sessile organisms, plants must tolerate various environmental stresses. Plant hormones play vital roles in plant responses to biotic and abiotic stresses. Among these hormones, jasmonic acid (JA) and its precursors and derivatives (jasmonates, JAs) play important roles in the mediation of plant responses and defenses to biotic and abiotic stresses and have received extensive research attention. Although some reviews of JAs are available, this review focuses on JAs in the regulation of plant stress responses, as well as JA synthesis, metabolism, and signaling pathways. We summarize recent progress in clarifying the functions and mechanisms of JAs in plant responses to abiotic stresses (drought, cold, salt, heat, and heavy metal toxicity) and biotic stresses (pathogen, insect, and herbivore). Meanwhile, the crosstalk of JA with various other plant hormones regulates the balance between plant growth and defense. Therefore, we review the crosstalk of JAs with other phytohormones, including auxin, gibberellic acid, salicylic acid, brassinosteroid, ethylene, and abscisic acid. Finally, we discuss current issues and future opportunities in research into JAs in plant stress responses.
PMID: 34445272
Int J Mol Sci , IF:5.923 , 2021 Aug , V22 (16) doi: 10.3390/ijms22168400
Optimal Brassinosteroid Levels Are Required for Soybean Growth and Mineral Nutrient Homeostasis.
College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.; College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Brassinosteroids (BRs) are steroid phytohormones that are known to regulate plant growth and nutrient uptake and distribution. However, how BRs regulate nutrient uptake and balance in legume species is not fully understood. Here, we show that optimal BR levels are required for soybean (Glycine max L.) seedling growth, as treatments with both 24-epicastasterone (24-epiCS) and the BR biosynthesis inhibitor propiconazole (PPZ) inhibit root growth, including primary root elongation and lateral root formation and elongation. Specifically, 24-epiCS and PPZ reduced the total phosphorus and potassium levels in the shoot and affected several minor nutrients, such as magnesium, iron, manganese, and molybdenum. A genome-wide transcriptome analysis identified 3774 and 4273 differentially expressed genes in the root tip after brassinolide and PPZ treatments, respectively. The gene ontology (GO) analysis suggested that genes related to "DNA-replication", "microtubule-based movement", and "plant-type cell wall organization" were highly responsive to the brassinolide and PPZ treatments. Furthermore, consistent with the effects on the nutrient concentrations, corresponding mineral transporters were found to be regulated by BR levels, including the GmPHT1s, GmKTs, GmVIT2, GmZIPs, and GmMOT1 genes. Our study demonstrates that optimal BR levels are important for growth and mineral nutrient homeostasis in soybean seedlings.
PMID: 34445112
Front Plant Sci , IF:5.753 , 2021 , V12 : P718091 doi: 10.3389/fpls.2021.718091
14-3-3 Proteins Are Involved in BR-Induced Ray Petal Elongation in Gerbera hybrida.
Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China.; College of Landscape Architecture and Art, Henan Agricultural University, Zhengzhou, China.
14-3-3 proteins play a major role in the regulation of primary metabolism, protein transport, ion channel activity, signal transduction and biotic/abiotic stress responses. However, their involvement in petal growth and development is largely unknown. Here, we identified and characterized the expression patterns of seven genes of the 14-3-3 family in gerbera. While none of the genes showed any tissue or developmental specificity of spatiotemporal expression, all seven predicted proteins have the nine alpha-helices typical of 14-3-3 proteins. Following treatment with brassinolide, an endogenous brassinosteroid, the Gh14-3-3 genes displayed various response patterns; for example, Gh14-3-3b and Gh14-3-3f reached their highest expression level at early (2 h) and late (24 h) timepoints, respectively. Further study revealed that overexpression of Gh14-3-3b or Gh14-3-3f promoted cell elongation, leading to an increase in ray petal length. By contrast, silencing of Gh14-3-3b or Gh14-3-3f inhibited petal elongation, which was eliminated partly by brassinolide. Correspondingly, the expression of petal elongation-related and brassinosteroid signaling-related genes was modified in transgenic petals. Taken together, our research suggests that Gh14-3-3b and Gh14-3-3f are positive regulators of brassinosteroid-induced ray petal elongation and thus provides novel insights into the molecular mechanism of petal growth and development.
PMID: 34421972
Front Plant Sci , IF:5.753 , 2021 , V12 : P671713 doi: 10.3389/fpls.2021.671713
Auxin Metabolism Is Involved in Fruit Set and Early Fruit Development in the Parthenocarpic Tomato "R35-P".
Key Laboratory of Molecular Module-Based Breeding of High Yield and Abiotic Resistant Plants in Universities of Shandong (Ludong University), College of Agriculture, Ludong University, Yantai, China.; Institute of Vegetable, Gansu Academy of Agricultural Science, Lanzhou, China.; College of Horticulture, China Agricultural University, Beijing, China.; Agricultural and Rural Bureau of Shouguang, Shouguang, China.
Parthenocarpic tomato can set fruit and develop without pollination and exogenous hormone treatments under unfavorable environmental conditions, which is beneficial to tomato production from late fall to early spring in greenhouses. In this study, the endogenous hormones in the ovaries of the parthenocarpic tomato line "R35-P" (stigma removed or self-pollination) and the non-parthenocarpic tomato line "R35-N" (self-pollination) at four stages between preanthesis and postanthesis investigated, using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). A nearly twofold IAA (indoleacetic acid) content was found in "R35-P" rather than in "R35-N" at -2 and 0 days after anthesis (DAA). Except at -2 DAA, a lower ABA (abscisic acid) content was observed in Pe (stigma removed in "R35-P") compared to that in Ps (self-pollination in "R35-P") or CK (self-pollination in "R35-N"). After pollination, although the content of GA1 (gibberellins acid 1) in CK increased, the levels of GAs (gibberellins acids) were notably low. At all four stages, a lower SA (salicylic acid) content was found in Ps and CK than in Pe, while the content and the change trend were similar in Ps and CK. The variation tendencies of JA (jasmonic acid) varied among Pe, Ps, and CK at the studied periods. Furthermore, KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses of transcriptomic data identified 175 differentially expressed genes (DEGs) related to plant hormone signal transduction, including 63 auxin-related genes, 27 abscisic acid-related genes, 22 ethylene-related genes, 16 cytokinin-related genes, 16 salicylic acid-related genes, 14 brassinosteroid-related genes, 13 jasmonic acid-related genes, and 4 gibberellin-related genes at -2 DAA and 0 DAA. Our results suggest that the fate of a fruit set or degeneration occurred before anthesis in tomato. Auxins, whose levels were independent of pollination and fertilization, play prominent roles in controlling a fruit set in "R35-P," and other hormones are integrated in a synergistic or antagonistic way.
PMID: 34408758
Theor Appl Genet , IF:5.699 , 2021 Aug doi: 10.1007/s00122-021-03939-3
GW10, a member of P450 subfamily regulates grain size and grain number in rice.
Guangdong Provincial Key Laboratory of Plant Molecular Breeding, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China.; Guangdong Provincial Key Laboratory of Plant Molecular Breeding, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China. gqzhang@scau.edu.cn.; Guangdong Provincial Key Laboratory of Plant Molecular Breeding, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, China. shaokuiwang@scau.edu.cn.
KEY MESSAGE: A quantitative trait locus GW10 is located on Chromosome 10 by map-based cloning, which encodes a P450 Subfamily protein. The GW10 regulates grain size and grain number in rice involved in the BR pathway. Grain size and grain number play extremely important roles in rice grain yield. Here, we identify GW10, which encodes a P450 subfamily protein and controls grain size and grain number by using Lemont (tropical japonica) as donor parent and HJX74 (indica) as recipient parent. The GW10 locus was mapped into a 14.6 kb region in HJX74 genomic on the long arm of chromosome 10. Lower expression of the gw10 in panicle is contributed to the shorter and narrower rice grain, and the increased number of grains per panicle. In contrast, overexpression of GW10 is contributed to longer and wider rice grain. Furthermore, the higher expression levels of some of the brassinosteroid (BR) biosynthesis and response genes are associated with the NIL-GW10. The sensitivity of the leaf angle to exogenous BR in NIL-GW10 is lower than that in NIL-gw10 and in the KO-GW10, which implied that the GW10 should involve in the brassinosteroid-mediated regulation of rice grain size and grain number.
PMID: 34420062
iScience , IF:5.458 , 2021 Aug , V24 (8) : P102926 doi: 10.1016/j.isci.2021.102926
SlBES1 promotes tomato fruit softening through transcriptional inhibition of PMEU1.
Key Laboratory of Horticultural Plant Growth and Development, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310058, PR China.; College of Plant Science, Jilin University, Changchun, Jilin 130062, PR China.; Key Laboratory of Protected Horticulture of Ministry of Education, College of Horticulture, Shenyang Agricultural University, Shenyang 110866, PR China.; Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.; State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100097, PR China.
Fruit softening indicated by firmness determines the texture, transportability, and shelf life of tomato products. However, the regulatory mechanism underlying firmness formation in tomato fruit is poorly understood. Here, we report the regulatory role of SlBES1, an essential component of brassinosteroid hormone signaling, in tomato fruit softening. We found that SlBES1 promotes fruit softening during tomato fruit ripening and postharvest storage. RNA-seq analysis suggested that PMEU1, which encodes a pectin methylesterase, might participate in SlBES1-mediated softening. Biochemical and immunofluorescence assays indicated that SlBES1 inhibited PMEU1-related pectin de-methylesterification. Further molecular and genetic evidence verified that SlBES1 directly binds to the E-box of PMEU1 to repress its expression, leading to fruits softening. Loss-of-function SlBES1 mutant generated by CRISPR-Cas9 showed firmer fruits and longer shelf life during postharvest storage without other quality alteration. Collectively, our results indicated the potential of manipulating SlBES1 to regulate firmness without negative consequence on visual and nutrition quality.
PMID: 34430815
Plant Cell Rep , IF:4.57 , 2021 Aug doi: 10.1007/s00299-021-02763-9
Exogenous brassinosteroid and jasmonic acid improve drought tolerance in Brassica rapa L. genotypes by modulating osmolytes, antioxidants and photosynthetic system.
Plant Molecular Biology Laboratory, Department of Botany, University of Kashmir, Srinagar, 190 006, Kashmir, India.; Plant Molecular Biology Laboratory, Department of Botany, University of Kashmir, Srinagar, 190 006, Kashmir, India. riffatminhaj@kashmiruniversity.ac.in.
KEY MESSAGE: Exogenously supplied BR and JA help KS101 and KBS3 genotypes of Brassica rapa to alleviate drought stress by modifying osmolyte concentration, levels of antioxidant enzymes and photosynthetic system. Oilseed plants are susceptible to drought stress and a significant loss in yield has been reported during recent decades. Thus, it is imperative to understand the various underlying drought response mechanisms in Brassica oilseed plants to formulate the sustainable strategies to protect the crop yield under water-limiting conditions. Phytohormones play a key role in fine-tuning various regulatory mechanisms for drought stress adaptation in plants, and the present study explores the response of several physiological stress markers by exogenous supplementation of 24-epibrassinolide (EBL) and jasmonic acid (JA) on two genotypes of Brassica rapa, KS101 and KBS3 under drought stress conditions. The exogenous application of BR and JA, separately or in combination, significantly alleviated the drought stress by improving photosynthetic rate, photosynthetic pigments, stomatal conductance, transpiration rate and antioxidant defence. We observed that concentration of different osmolytes increased and membrane damage significantly reduced by the application of BR and JA. The overall activity of antioxidant enzymes POD, CAT, GR, APX and CAT elevated during all the treatments, be it stress alone or in combination with BR and JA, compared to the control. However, we observed that the BR was much better in mitigating the drought stress compared to JA. Thus, the present study suggests that BR and JA supplementation improves the performance of B. rapa on exposure to drought stress, which hints at the critical role of BR and JA in improving crop productivity in drought-prone areas.
PMID: 34374791
BMC Plant Biol , IF:4.215 , 2021 Aug , V21 (1) : P375 doi: 10.1186/s12870-021-03066-7
RNA-Seq analysis reveals potential regulators of programmed cell death and leaf remodelling in lace plant (Aponogeton madagascariensis).
Department of Biology, Dalhousie University, Halifax, NS, Canada.; Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, Canada.; Department of Biology, University of Prince Edward Island, Charlottetown, PEI, Canada.; Department of Biology, Dalhousie University, Halifax, NS, Canada. Arunika.gunawardena@dal.ca.
BACKGROUND: The lace plant (Aponogeton madagascariensis) is an aquatic monocot that develops leaves with uniquely formed perforations through the use of a developmentally regulated process called programmed cell death (PCD). The process of perforation formation in lace plant leaves is subdivided into several developmental stages: pre-perforation, window, perforation formation, perforation expansion and mature. The first three emerging "imperforate leaves" do not form perforations, while all subsequent leaves form perforations via developmentally regulated PCD. PCD is active in cells called "PCD cells" that do not retain the antioxidant anthocyanin in spaces called areoles framed by the leaf veins of window stage leaves. Cells near the veins called "NPCD cells" retain a red pigmentation from anthocyanin and do not undergo PCD. While the cellular changes that occur during PCD are well studied, the gene expression patterns underlying these changes and driving PCD during leaf morphogenesis are mostly unknown. We sought to characterize differentially expressed genes (DEGs) that mediate lace plant leaf remodelling and PCD. This was achieved performing gene expression analysis using transcriptomics and comparing DEGs among different stages of leaf development, and between NPCD and PCD cells isolated by laser capture microdissection. RESULTS: Transcriptomes were sequenced from imperforate, pre-perforation, window, and mature leaf stages, as well as PCD and NPCD cells isolated from window stage leaves. Differential expression analysis of the data revealed distinct gene expression profiles: pre-perforation and window stage leaves were characterized by higher expression of genes involved in anthocyanin biosynthesis, plant proteases, expansins, and autophagy-related genes. Mature and imperforate leaves upregulated genes associated with chlorophyll development, photosynthesis, and negative regulators of PCD. PCD cells were found to have a higher expression of genes involved with ethylene biosynthesis, brassinosteroid biosynthesis, and hydrolase activity whereas NPCD cells possessed higher expression of auxin transport, auxin signalling, aspartyl proteases, cysteine protease, Bag5, and anthocyanin biosynthesis enzymes. CONCLUSIONS: RNA sequencing was used to generate a de novo transcriptome for A. madagascariensis leaves and revealed numerous DEGs potentially involved in PCD and leaf remodelling. The data generated from this investigation will be useful for future experiments on lace plant leaf development and PCD in planta.
PMID: 34388962
PeerJ , IF:2.984 , 2021 , V9 : Pe11755 doi: 10.7717/peerj.11755
Identification and expression profile of the soil moisture and Ralstonia solanacearum response CYPome in ginger (Zingiber officinale).
College of Pharmaceutical Science and Chinese Medicine, Southwest University, Chongqing, Chongqing, China.; Research Institute for Special Plants, Chongqing University of Arts and Sciences, Yongchuan, Chongqing, China.; Chongqing Key Laboratory of Economic Plant Biotechnology, Yongchuan, Chongqing, China.
Background: Cytochrome P450s play crucial roles in various biosynthetic reactions. Ginger (Zingiber officinale), which is often threatened by Ralstonia solanacearum, is the most economically important crop in the family Zingiberaceae. Whether the cytochrome P450 complement (CYPome) significantly responds to this pathogen has remained unclear. Methods: Transcriptomic responses to R. solanacearum and soil moisture were analyzed in ginger, and expression profiles of the CYPome were determined based on transcriptome data. Results: A total of 821 P450 unigenes with ORFs >/= 300 bp were identified. Forty percent soil moisture suppressed several key P450 unigenes involved in the biosynthesis of flavonoids, gingerols, and jasmonates, including unigenes encoding flavonoid 3'-hydroxylase, flavonoid 3',5'-hydroxylase, steroid 22-alpha-hydroxylase, cytochrome P450 family 724 subfamily B polypeptide 1, and allene oxide synthase. Conversely, the expression of P450 unigenes involved in gibberellin biosynthesis and abscisic acid catabolism, encoding ent-kaurene oxidase and abscisic acid 8'-hydroxylase, respectively, were promoted by 40% soil moisture. Under R. solanacearum infection, the expression of P450 unigenes involved in the biosynthesis of the above secondary metabolites were changed, but divergent expression patterns were observed under different soil moisture treatments. High moisture repressed expression of genes involved in flavonoid, brassinosteroid, gingerol, and jasmonate biosynthesis, but promoted expression of genes involved in GA anabolism and ABA catabolism. These results suggest possible mechanisms for how high moisture causes elevated susceptibility to R. solanacearum infection.
PMID: 34414026
Plant Signal Behav , IF:2.247 , 2021 Aug : P1963583 doi: 10.1080/15592324.2021.1963583
24-epibrassinolide confers tolerance against deep-seeding stress in Zea mays L. coleoptile development by phytohormones signaling transduction and their interaction network.
Gansu Provincial Key Laboratory of Aridland Crop Science/College of Agronomy, Gansu Agricultural University, Lanzhou, P.R. China.; Crop Research Institute, Gansu Academy of Agricultural Sciences, Lanzhou, P.R. China.
Coleoptile/mesocotyl elongation influence seedling emergence and establishment, is major causes of maize deep-seeding tolerance (DST). Detailed analyses on molecular basis underlying their elongation mediated by brassinosteroid under deep-seeding stress (DSS) could provide meaningful information for key factors controlling their elongation. Here we monitored transcriptome and phytohormones changes specifically in elongating coleoptile/mesocotyl in response to DSS and 24-epibrassinolide (EBR)-signaling. Phenotypically, contrasting maize evolved variant organs to positively respond to DST, longer coleoptile/mesocoty of K12/W64A was a desirable organ for seedling under DSS. Applied-EBR improved maize DST, and their coleoptiles/mesocotyls were further elongated. 15,607/20,491 differentially expressed genes (DEGs) were identified in W64A/K12 coleoptile, KEGG analysis showed plant hormone signal transduction, starch and sucrose metabolism, valine, leucine, and isoleucine degradation were critical processes of coleoptile elongation under DSS and EBR signaling, further highly interconnected network maps including 79/142 DEGs for phytohormones were generated. Consistent with these DEGs expression, interactions, and transport, IAA, GA3, ABA, and Cis-ZT were significantly reduced while EBR, Trans-ZT, JA, and SA were clearly increased in coleoptile under DSS and EBR-signaling. These results enrich our knowledge about the genes and phytohormones regulating coleoptile elongation in maize, and help improve future studies on corresponding genes and develop varieties with DST.
PMID: 34425064
Genes Genomics , IF:1.839 , 2021 Aug doi: 10.1007/s13258-021-01148-2
Phosphorylation of BIK1 is critical for interaction with downstream signaling components.
Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea.; Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea. manhooh@cnu.ac.kr.
BACKGROUND: Botrytis-induced Kinase 1 (BIK1) is a receptor-like cytoplasmic kinase (RLCK) involved in the defense, growth, and development of higher plants. It interacts with various receptor-like kinases (RLKs) such as Brassinosteroid Insensitive 1 (BRI1), Flagellin Sensitive 2 (FLS2), and Perception of the Arabidopsis Danger Signal Peptide 1 (PEPR1), but little is known about signaling downstream of BIK1. OBJECTIVE: In this study, we aimed to identify Arabidopsis thaliana BIK1 (AtBIK1) and Brassica rapa BIK1 (BrBIK1) interacting proteins, which is downstream signaling components in Arabidopsis. In addition, the effect of BIK1 phosphorylation on their interaction were examined. METHODS: For yeast two hybrid (Y2H) screening, a B. rapa cDNA activation domain (AD) library and an A. thaliana cDNA library were used. Reverse reaction (LR) recombinations of appropriate open reading frames (AtBIK1, BrBIK1, AtRGP2, AtPATL2, AtPP7) in either pDONR207 or pDONR/zeo were performed with the split-YFP destination vectors pDEST-GWVYNE and pDEST-GWVYCE to generate N- or C-terminal fusions with the N- and C-terminal yellow fluorescent protein (YFP) moieties, respectively. Recombined vectors were transformed into Agrobacterium strain GV3101. The described GST-AtBIK1, Flag-AtBIK1, and Flag-BrBIK1 constructs were used as templates for site-directed mutagenesis with a QuikChange XL Site-Directed Mutagenesis Kit (Stratagene). RESULTS: In results, A. thaliana BIK1 (AtBIK1) displays strong autophosphorylation kinase activity on tyrosine and threonine residues, whereas B. rapa BIK1 (BrBIK1) does not exhibit autophosphorylation kinase activity in vitro. Herein, we demonstrated that four proteins (RGP2, PATL2, PP7, and SULTR4.1) interact with BrBIK1 but not AtBIK1 in a Y2H system. To confirm interactions between BIK1 and protein candidates in Nicotiana benthamiana, BiFC analysis was performed and it was found that only BrBIK1 bound the three proteins tested. Three phosphosites, T90, T362, and T368, based on amino acid sequence alignment between AtBIK1 and BrBIK1, and performed site-directed mutagenesis (SDM) on AtBIK1 and BrBIK. S90T, P362T, and A369T mutations in BrBIK1 restored autophosphorylation kinase activity on threonine residues comparable to AtBIK1. However, T90A, T362P, and T368A mutations in AtBIK1 did not alter autophosphorylation kinase activity on threonine residues compared with wild-type AtBIK1. BiFC results showed that BIK1 mutations restored kinase activity led to the loss of the binding activity to RGP2, PATL2, or PP7 proteins. CONCLUSION: Phospho-BIK1 might be involved in plant innate immunity, while non-phospho BIK1 may regulate plant growth and development through interactions with RGP2, PATL2, and PP7.
PMID: 34449065