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Xu D, Tang W, Ma Y, Wang X, Yang Y, Wang X, Xie L, Huang S, Qin T, Tang W, Xu Z, Li L, Tang Y, Chen M, Ma Y. Arabidopsis G-protein β subunit AGB1 represses abscisic acid signaling via attenuation of the MPK3-VIP1 phosphorylation cascade. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1615-1632. [PMID: 37988280 DOI: 10.1093/jxb/erad464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 11/20/2023] [Indexed: 11/23/2023]
Abstract
Heterotrimeric G proteins play key roles in cellular processes. Although phenotypic analyses of Arabidopsis Gβ (AGB1) mutants have implicated G proteins in abscisic acid (ABA) signaling, the AGB1-mediated modules involved in ABA responses remain unclear. We found that a partial AGB1 protein was localized to the nucleus where it interacted with ABA-activated VirE2-interacting protein 1 (VIP1) and mitogen-activated protein kinase 3 (MPK3). AGB1 acts as an upstream negative regulator of VIP1 activity by initiating responses to ABA and drought stress, and VIP1 regulates the ABA signaling pathway in an MPK3-dependent manner in Arabidopsis. AGB1 outcompeted VIP1 for interaction with the C-terminus of MPK3, and prevented phosphorylation of VIP1 by MPK3. Importantly, ABA treatment reduced AGB1 expression in the wild type, but increased in vip1 and mpk3 mutants. VIP1 associates with ABA response elements present in the AGB1 promoter, forming a negative feedback regulatory loop. Thus, our study defines a new mechanism for fine-tuning ABA signaling through the interplay between AGB1 and MPK3-VIP1. Furthermore, it suggests a common G protein mechanism to receive and transduce signals from the external environment.
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Affiliation(s)
- Dongbei Xu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Wensi Tang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Yanan Ma
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Xia Wang
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Yanzhi Yang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Xiaoting Wang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Lina Xie
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Suo Huang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Tengfei Qin
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Weilin Tang
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Zhaoshi Xu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Lei Li
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yimiao Tang
- Institute of Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
| | - Ming Chen
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Youzhi Ma
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
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Zait Y, Joseph A, Assmann SM. Stomatal responses to VPD utilize guard cell intracellular signaling components. FRONTIERS IN PLANT SCIENCE 2024; 15:1351612. [PMID: 38375078 PMCID: PMC10875092 DOI: 10.3389/fpls.2024.1351612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 01/17/2024] [Indexed: 02/21/2024]
Abstract
Stomatal pores, vital for CO2 uptake and water loss regulation in plants, are formed by two specialized guard cells. Despite their importance, there is limited understanding of how guard cells sense and respond to changes in vapor pressure difference (VPD). This study leverages a selection of CO2 hyposensitive and abscisic acid (ABA) signaling mutants in Arabidopsis, including heterotrimeric G protein mutants and RLK (receptor-like kinase) mutants, along with a variety of canola cultivars to delve into the intracellular signaling mechanisms prompting stomatal closure in response to high VPD. Stomatal conductance response to step changes in VPD was measured using the LI-6800F gas exchange system. Our findings highlight that stomatal responses to VPD utilize intracellular signaling components. VPD hyposensitivity was particularly evident in mutants of the ht1 (HIGH LEAF TEMPERATURE1) gene, which encodes a protein kinase expressed mainly in guard cells, and in gpa1-3, a null mutant of the sole canonical heterotrimeric Gα subunit, previously implicated in stomatal signaling. Consequently, this research identifies a nexus in the intricate relationships between guard cell signal perception, stomatal conductance, environmental humidity, and CO2 levels.
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Affiliation(s)
- Yotam Zait
- Biology Department, Penn State University, Mueller Laboratory, University Park, PA, United States
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ariel Joseph
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Sarah M. Assmann
- Biology Department, Penn State University, Mueller Laboratory, University Park, PA, United States
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Kong J, Chen R, Liu R, Wang W, Wang S, Zhang J, Yang N. PLC1 mediated Cycloastragenol-induced stomatal movement by regulating the production of NO in Arabidopsis thaliana. BMC PLANT BIOLOGY 2023; 23:571. [PMID: 37978426 PMCID: PMC10655312 DOI: 10.1186/s12870-023-04555-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 10/23/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND Astragalus grows mainly in drought areas. Cycloastragenol (CAG) is a tetracyclic triterpenoid allelochemical extracted from traditional Chinese medicine Astragalus root. Phospholipase C (PLC) and Gα-submit of the heterotrimeric G-protein (GPA1) are involved in many biotic or abiotic stresses. Nitric oxide (NO) is a crucial gas signal molecule in plants. RESULTS In this study, using the seedlings of Arabidopsis thaliana (A. thaliana), the results showed that low concentrations of CAG induced stomatal closure, and high concentrations inhibited stomatal closure. 30 µmol·L-1 CAG significantly increased the relative expression levels of PLC1 and GPA1 and the activities of PLC and GTP hydrolysis. The stomatal aperture of plc1, gpa1, and plc1/gpa1 was higher than that of WT under CAG treatment. CAG increased the fluorescence intensity of NO in guard cells. Exogenous application of c-PTIO to WT significantly induced stomatal aperture under CAG treatment. CAG significantly increased the relative expression levels of NIA1 and NOA1. Mutants of noa1, nia1, and nia2 showed that NO production was mainly from NOA1 and NIA1 by CAG treatment. The fluorescence intensity of NO in guard cells of plc1, gpa1, and plc1/gpa1 was lower than WT, indicating that PLC1 and GPA1 were involved in the NO production in guard cells. There was no significant difference in the gene expression of PLC1 in WT, nia1, and noa1 under CAG treatment. The gene expression levels of NIA1 and NOA1 in plc1, gpa1, and plc1/gpa1 were significantly lower than WT, indicating that PLC1 and GPA1 were positively regulating NO production by regulating the expression of NIA1 and NOA1 under CAG treatment. CONCLUSIONS These results suggested that the NO accumulation was essential to induce stomatal closure under CAG treatment, and GPA1 and PLC1 acted upstream of NO.
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Affiliation(s)
- Juantao Kong
- College of Life Science, Northwest Normal University, Lanzhou, 730070, China
| | - Rongshan Chen
- College of Life Science, Northwest Normal University, Lanzhou, 730070, China
| | - Ruirui Liu
- College of Life Science, Northwest Normal University, Lanzhou, 730070, China
| | - Wei Wang
- College of Life Science, Northwest Normal University, Lanzhou, 730070, China
| | - Simin Wang
- College of Life Science, Northwest Normal University, Lanzhou, 730070, China
| | - Jinping Zhang
- College of Life Science, Northwest Normal University, Lanzhou, 730070, China
| | - Ning Yang
- College of Life Science, Northwest Normal University, Lanzhou, 730070, China.
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Afrin T, Costello CN, Monella AN, Kørner CJ, Pajerowska-Mukhtar KM. The interplay of GTP-binding protein AGB1 with ER stress sensors IRE1a and IRE1b modulates Arabidopsis unfolded protein response and bacterial immunity. PLANT SIGNALING & BEHAVIOR 2022; 17:2018857. [PMID: 34968413 PMCID: PMC8920210 DOI: 10.1080/15592324.2021.2018857] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/10/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
In eukaryotic cells, the accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) results in ER stress that induces a cascade of reactions called the unfolded protein response (UPR). In Arabidopsis, the most conserved UPR sensor, Inositol-requiring enzyme 1 (IRE1), responds to both abiotic- and biotic-induced ER stress. Guanine nucleotide-binding proteins (G proteins) constitute another universal and conserved family of signal transducers that have been extensively investigated due to their ubiquitous presence and diverse nature of action. Arabidopsis GTP-binding protein β1 (AGB1) is the only G-protein β-subunit encoded by the Arabidopsis genome that is involved in numerous signaling pathways. Mounting evidence suggests the existence of a crosstalk between IRE1 and G protein signaling during ER stress. AGB1 has previously been shown to control a distinct UPR pathway independently of IRE1 when treated with an ER stress inducer tunicamycin. Our results obtained with combinatorial knockout mutants support the hypothesis that both IRE1 and AGB1 synergistically contribute to ER stress responses chemically induced by dithiothreitol (DTT) as well as to the immune responses against a phytopathogenic bacterium Pseudomonas syringae pv. tomato strain DC3000. Our study highlights the crosstalk between the plant UPR transducers under abiotic and biotic stress.
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Affiliation(s)
- Taiaba Afrin
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd, Birmingham, AL, USA
| | - Caitlin N. Costello
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd, Birmingham, AL, USA
| | - Amber N. Monella
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd, Birmingham, AL, USA
| | - Camilla J. Kørner
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd, Birmingham, AL, USA
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5
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Brunetti SC, Arseneault MKM, Gulick PJ. The caleosin CLO7 and its role in the heterotrimeric G-protein signalling network. JOURNAL OF PLANT PHYSIOLOGY 2022; 279:153841. [PMID: 36334585 DOI: 10.1016/j.jplph.2022.153841] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 10/07/2022] [Accepted: 10/08/2022] [Indexed: 06/16/2023]
Abstract
The investigation of the caleosin CLO7 in relation to heterotrimeric G-protein signalling in Arabidopsis showed that the gene plays a role in seed germination and embryo viability. The caleosin CLO7 belongs to a multi-gene family of calcium-binding proteins which are characterized by single EF-hand motifs. Other members of the caleosin gene family have been shown to affect transpiration and seed germination as well as play a role in both abiotic and biotic stress responses. The proteins are associated with lipid droplets/oil bodies and some members of the gene family have been shown to have peroxygenase activity. Members of the gene family have also been shown to interact with the α subunit of the heterotrimeric G protein complex. In this study, we further expand on the diversity of physiological responses in which members of this gene family play regulatory roles. Utilizing BiFC and Y2H protein-protein interaction assays, CLO7 is identified as an interactor of the heterotrimeric G protein α subunit, GPA1. The full-length CLO7 is shown to interact with both the wild-type GPA1 and its constitutively active form, GPA1QL, at the plasma membrane. Point mutations to critical amino acids for calcium binding in the EF-hand of CLO7 indicate that the interaction with GPA1 is calcium-dependent and that the interaction with GPA1QL is enhanced by calcium. Protein-protein interaction assays also show that CLO7 interacts with Pirin1, a member of the cupin gene superfamily and a known downstream effector of GPA1, and this interaction is calcium-dependent. The N-terminal portion of CLO7 is responsible for these interactions. GFP-tagged CLO7 protein localizes to the endoplasmic reticulum (ER) and to lipid bodies. Characterization of the clo7 mutant line has shown that CLO7 is implicated in the abscisic acid (ABA) and mannitol-mediated inhibition of seed germination, with the clo7 mutant displaying higher germination rates in response to osmotic stress and ABA hormone treatment. These results provide insight into the role of CLO7 in seed germination in response to abiotic stress as well as its interaction with GPA1 and Pirin1. CLO7 also plays a role in embryo viability with the clo7gpa1 double mutant displaying embryo lethality, and therefore the double mutant cannot be recovered.
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Affiliation(s)
- Sabrina C Brunetti
- Biology Department, Concordia University, 7141 Sherbrooke W. Montreal (Quebec) H4B 1R6, Canada
| | - Michelle K M Arseneault
- Biology Department, Concordia University, 7141 Sherbrooke W. Montreal (Quebec) H4B 1R6, Canada
| | - Patrick J Gulick
- Biology Department, Concordia University, 7141 Sherbrooke W. Montreal (Quebec) H4B 1R6, Canada.
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Li X, Deng D, Cataltepe G, Román Á, Buckley CR, Cassano Monte‐Bello C, Skirycz A, Caldana C, Haydon MJ. A reactive oxygen species Ca 2+ signalling pathway identified from a chemical screen for modifiers of sugar-activated circadian gene expression. THE NEW PHYTOLOGIST 2022; 236:1027-1041. [PMID: 35842791 PMCID: PMC9804775 DOI: 10.1111/nph.18380] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 07/13/2022] [Indexed: 06/10/2023]
Abstract
Sugars are essential metabolites for energy and anabolism that can also act as signals to regulate plant physiology and development. Experimental tools to disrupt major sugar signalling pathways are limited. We performed a chemical screen for modifiers of activation of circadian gene expression by sugars to discover pharmacological tools to investigate and manipulate plant sugar signalling. Using a library of commercially available bioactive compounds, we identified 75 confident hits that modified the response of a circadian luciferase reporter to sucrose in dark-adapted Arabidopsis thaliana seedlings. We validated the transcriptional effect on a subset of the hits and measured their effects on a range of sugar-dependent phenotypes for 13 of these chemicals. Chemicals were identified that appear to influence known and unknown sugar signalling pathways. Pentamidine isethionate was identified as a modifier of a sugar-activated Ca2+ signal that acts as a calmodulin inhibitor downstream of superoxide in a metabolic signalling pathway affecting circadian rhythms, primary metabolism and plant growth. Our data provide a resource of new experimental tools to manipulate plant sugar signalling and identify novel components of these pathways.
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Affiliation(s)
- Xiang Li
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
| | - Dongjing Deng
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
| | - Gizem Cataltepe
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
- Max Planck Institute of Molecular Plant Physiology14476PotsdamGermany
| | - Ángela Román
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
| | | | | | | | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology14476PotsdamGermany
| | - Michael J. Haydon
- School of BioSciencesUniversity of MelbourneParkvilleVic.3010Australia
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7
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Chen Q, Hou S, Pu X, Li X, Li R, Yang Q, Wang X, Guan M, Rengel Z. Dark secrets of phytomelatonin. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:5828-5839. [PMID: 35522068 DOI: 10.1093/jxb/erac168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 04/19/2022] [Indexed: 06/14/2023]
Abstract
Phytomelatonin is a newly identified plant hormone, and its primary functions in plant growth and development remain relatively poorly appraised. Phytomelatonin is a master regulator of reactive oxygen species (ROS) signaling and acts as a darkness signal in circadian stomatal closure. Plants exhibit at least three interrelated patterns of interaction between phytomelatonin and ROS production. Exogenous melatonin can induce flavonoid biosynthesis, which might be required for maintenance of antioxidant capacity under stress, after harvest, and in leaf senescence conditions. However, several genetic studies have provided direct evidence that phytomelatonin plays a negative role in the biosynthesis of flavonoids under non-stress conditions. Phytomelatonin delays flowering time in both dicot and monocot plants, probably via its receptor PMTR1 and interactions with the gibberellin, strigolactone, and ROS signaling pathways. Furthermore, phytomelatonin signaling also functions in hypocotyl and shoot growth in skotomorphogenesis and ultraviolet B (UV-B) exposure; the G protein α-subunit (Arabidopsis GPA1 and rice RGA1) and constitutive photomorphogenic1 (COP1) are important signal components during this process. Taken together, these findings indicate that phytomelatonin acts as a darkness signal with important regulatory roles in circadian stomatal closure, flavonoid biosynthesis, flowering, and hypocotyl and shoot growth.
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Affiliation(s)
- Qi Chen
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Suying Hou
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Xiaojun Pu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Xiaomin Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Rongrong Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Qian Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Xinjia Wang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Miao Guan
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Zed Rengel
- UWA School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Perth WA, Australia
- Institute for Adriatic Crops and Karst Reclamation, Split, Croatia
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8
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Boonyaves K, Wu TY, Dong Y, Urano D. Interplay between ARABIDOPSIS Gβ and WRKY transcription factors differentiates environmental stress responses. PLANT PHYSIOLOGY 2022; 190:813-827. [PMID: 35748759 PMCID: PMC9434291 DOI: 10.1093/plphys/kiac305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Different environmental stresses often evoke similar physiological disorders such as growth retardation; however, specific consequences reported among individual stresses indicate potential mechanisms to distinguish different stress types in plants. Here, we examined mechanisms to differentiate between stress types in Arabidopsis (Arabidopsis thaliana). Gene expression patterns recapitulating several abiotic stress responses suggested abscisic acid (ABA) as a mediator of the common stress response, while stress type-specific responses were related to metabolic adaptations. Transcriptome and metabolome analyses identified Arabidopsis Gβ (AGB1) mediating the common stress-responsive genes and primary metabolisms under nitrogen excess. AGB1 regulated the expressions of multiple WRKY transcription factors. Gene Ontology and mutant analyses revealed different roles among WRKYs: WRKY40 is involved in ABA and common stress responses, while WRKY75 regulates metabolic processes. The AGB1-WRKY signaling module controlled developmental plasticity in roots under nitrogen excess. Signal transmission from AGB1 to a selective set of WRKYs would be essential to evoke unique responses to different types of stresses.
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Affiliation(s)
| | - Ting-Ying Wu
- Temasek Life Sciences Laboratory, Singapore 117604, Singapore
| | - Yating Dong
- Temasek Life Sciences Laboratory, Singapore 117604, Singapore
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9
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Petutschnig E, Anders J, Stolze M, Meusel C, Hacke R, Much L, Schwier M, Gippert AL, Kroll S, Fasshauer P, Wiermer M, Lipka V. EXTRA LARGE G-PROTEIN2 mediates cell death and hyperimmunity in the chitin elicitor receptor kinase 1-4 mutant. PLANT PHYSIOLOGY 2022; 189:2413-2431. [PMID: 35522044 PMCID: PMC9342992 DOI: 10.1093/plphys/kiac214] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/13/2022] [Indexed: 05/08/2023]
Abstract
Heterotrimeric G-proteins are signal transduction complexes that comprised three subunits, Gα, Gβ, and Gγ, and are involved in many aspects of plant life. The noncanonical Gα subunit EXTRA LARGE G-PROTEIN2 (XLG2) mediates pathogen-associated molecular pattern (PAMP)-induced reactive oxygen species (ROS) generation and immunity downstream of pattern recognition receptors. A mutant of the chitin receptor component CHITIN ELICITOR RECEPTOR KINASE1 (CERK1), cerk1-4, maintains normal chitin signaling capacity but shows excessive cell death upon infection with powdery mildew fungi. We identified XLG2 mutants as suppressors of the cerk1-4 phenotype. Mutations in XLG2 complex partners ARABIDOPSIS Gβ1 (AGB1) and Gγ1 (AGG1) have a partial cerk1-4 suppressor effect. Contrary to its role in PAMP-induced immunity, XLG2-mediated control of ROS production by RESPIRATORY BURST OXIDASE HOMOLOGUE D (RBOHD) is not critical for cerk1-4-associated cell death and hyperimmunity. The cerk1-4 phenotype is also independent of the co-receptor/adapter kinases BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1) and SUPPRESSOR OF BIR1 1 (SOBIR1), but requires the E3 ubiquitin ligase PLANT U-BOX 2 (PUB2). XLG2 localizes to both the cell periphery and nucleus, and the cerk1-4 cell death phenotype is mediated by the cell periphery pool of XLG2. Integrity of the XLG2 N-terminal domain, but not its phosphorylation, is essential for correct XLG2 localization and formation of the cerk1-4 phenotype. Our results support a model in which XLG2 acts downstream of an unknown cell surface receptor that activates an NADPH oxidase-independent cell death pathway in Arabidopsis (Arabidopsis thaliana).
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Affiliation(s)
| | - Julia Anders
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Marnie Stolze
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Christopher Meusel
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Ronja Hacke
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Laura Much
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Melina Schwier
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Anna-Lena Gippert
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Samuel Kroll
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
| | - Patrick Fasshauer
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen 37077, Germany
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10
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Lin F, Cao J, Yuan J, Liang Y, Li J. Integration of Light and Brassinosteroid Signaling during Seedling Establishment. Int J Mol Sci 2021; 22:12971. [PMID: 34884771 PMCID: PMC8657978 DOI: 10.3390/ijms222312971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 11/27/2021] [Accepted: 11/27/2021] [Indexed: 01/02/2023] Open
Abstract
Light and brassinosteroid (BR) are external stimuli and internal cue respectively, that both play critical roles in a wide range of developmental and physiological process. Seedlings grown in the light exhibit photomorphogenesis, while BR promotes seedling etiolation. Light and BR oppositely control the development switch from shotomorphogenesis in the dark to photomorphogenesis in the light. Recent progress report that substantial components have been identified as hubs to integrate light and BR signals. Photomorphogenic repressors including COP1, PIFs, and AGB1 have been reported to elevate BR response, while photomorphogenesis-promoting factors such as HY5, BZS1, and NF-YCs have been proven to repress BR signal. In addition, BR components also modulate light signal. Here, we review the current research on signaling network associated with light and brassinosteroids, with a focus on the integration of light and BR signals enabling plants to thrive in the changeable environment.
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Affiliation(s)
- Fang Lin
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China; (J.C.); (J.Y.); (Y.L.); (J.L.)
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11
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Brunetti SC, Arseneault MKM, Wright JA, Wang Z, Ehdaeivand MR, Lowden MJ, Rivoal J, Khalil HB, Garg G, Gulick PJ. The stress induced caleosin, RD20/CLO3, acts as a negative regulator of GPA1 in Arabidopsis. PLANT MOLECULAR BIOLOGY 2021; 107:159-175. [PMID: 34599731 DOI: 10.1007/s11103-021-01189-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/05/2021] [Indexed: 06/13/2023]
Abstract
KEY MESSAGE A stress induced calcium-binding protein, RD20/CLO3 interacts with the alpha subunit of the heterotrimeric G-protein complex in Arabidopsis and affects etiolation and leaf morphology. Heterotrimeric G proteins and calcium signaling have both been shown to play a role in the response to environmental abiotic stress in plants; however, the interaction between calcium-binding proteins and G-protein signaling molecules remains elusive. We investigated the interaction between the alpha subunit of the heterotrimeric G-protein complex, GPA1, of Arabidopsis thaliana with the calcium-binding protein, the caleosin RD20/CLO3, a gene strongly induced by drought, salt and abscisic acid. The proteins were found to interact in vivo by bimolecular fluorescent complementation (BiFC); the interaction was localized to the endoplasmic reticulum and to oil bodies within the cell. The constitutively GTP-bound GPA1 (GPA1QL) also interacts with RD20/CLO3 as well as its EF-hand mutant variations and these interactions are localized to the plasma membrane. The N-terminal portion of RD20/CLO3 was found to be responsible for the interaction with GPA1 and GPA1QL using both BiFC and yeast two-hybrid assays. RD20/CLO3 contains a single calcium-binding EF-hand in the N-terminal portion of the protein; disruption of the calcium-binding capacity of the protein obliterates interaction with GPA1 in in vivo assays and decreases the interaction between the caleosin and the constitutively active GPA1QL. Analysis of rd20/clo3 mutants shows that RD20/CLO3 plays a key role in the signaling pathway controlling hypocotyl length in dark grown seedlings and in leaf morphology. Our findings indicate a novel role for RD20/CLO3 as a negative regulator of GPA1.
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Affiliation(s)
- Sabrina C Brunetti
- Department of Biology, Concordia University, 7141 Sherbrooke W., Montreal, QC, H4B 1R6, Canada
| | - Michelle K M Arseneault
- Department of Biology, Concordia University, 7141 Sherbrooke W., Montreal, QC, H4B 1R6, Canada
| | - Justin A Wright
- Department of Biology, Concordia University, 7141 Sherbrooke W., Montreal, QC, H4B 1R6, Canada
| | - Zhejun Wang
- Department of Biology, Concordia University, 7141 Sherbrooke W., Montreal, QC, H4B 1R6, Canada
| | | | - Michael J Lowden
- Department of Biology, Concordia University, 7141 Sherbrooke W., Montreal, QC, H4B 1R6, Canada
| | - Jean Rivoal
- Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal, QC, H1X 2B2, Canada
| | - Hala B Khalil
- Department of Biology, Concordia University, 7141 Sherbrooke W., Montreal, QC, H4B 1R6, Canada
- Department of Genetics, Faculty of Agriculture, Ain-Shams University, Shoubra El-khema, Cairo, Egypt
| | - Gajra Garg
- Department of Biology, Concordia University, 7141 Sherbrooke W., Montreal, QC, H4B 1R6, Canada
- Department of Biotechnology & Microbiology, Mahatma Jyoti Rao Phoole University, Jaipur, Rajasthan, India
| | - Patrick J Gulick
- Department of Biology, Concordia University, 7141 Sherbrooke W., Montreal, QC, H4B 1R6, Canada.
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12
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van der Woude L, Piotrowski M, Klaasse G, Paulus JK, Krahn D, Ninck S, Kaschani F, Kaiser M, Novák O, Ljung K, Bulder S, van Verk M, Snoek BL, Fiers M, Martin NI, van der Hoorn RAL, Robert S, Smeekens S, van Zanten M. The chemical compound 'Heatin' stimulates hypocotyl elongation and interferes with the Arabidopsis NIT1-subfamily of nitrilases. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:1523-1540. [PMID: 33768644 PMCID: PMC8360157 DOI: 10.1111/tpj.15250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/22/2021] [Indexed: 05/17/2023]
Abstract
Temperature passively affects biological processes involved in plant growth. Therefore, it is challenging to study the dedicated temperature signalling pathways that orchestrate thermomorphogenesis, a suite of elongation growth-based adaptations that enhance leaf-cooling capacity. We screened a chemical library for compounds that restored hypocotyl elongation in the pif4-2-deficient mutant background at warm temperature conditions in Arabidopsis thaliana to identify modulators of thermomorphogenesis. The small aromatic compound 'Heatin', containing 1-iminomethyl-2-naphthol as a pharmacophore, was selected as an enhancer of elongation growth. We show that ARABIDOPSIS ALDEHYDE OXIDASES redundantly contribute to Heatin-mediated hypocotyl elongation. Following a chemical proteomics approach, the members of the NITRILASE1-subfamily of auxin biosynthesis enzymes were identified among the molecular targets of Heatin. Our data reveal that nitrilases are involved in promotion of hypocotyl elongation in response to high temperature and Heatin-mediated hypocotyl elongation requires the NITRILASE1-subfamily members, NIT1 and NIT2. Heatin inhibits NIT1-subfamily enzymatic activity in vitro and the application of Heatin accordingly results in the accumulation of NIT1-subfamily substrate indole-3-acetonitrile in vivo. However, levels of the NIT1-subfamily product, bioactive auxin (indole-3-acetic acid), were also significantly increased. It is likely that the stimulation of hypocotyl elongation by Heatin might be independent of its observed interaction with NITRILASE1-subfamily members. However, nitrilases may contribute to the Heatin response by stimulating indole-3-acetic acid biosynthesis in an indirect way. Heatin and its functional analogues present novel chemical entities for studying auxin biology.
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Affiliation(s)
- Lennard van der Woude
- Molecular Plant PhysiologyInstitute of Environmental BiologyUtrecht UniversityPadualaan 8Utrecht3584 CHthe Netherlands
| | - Markus Piotrowski
- Department of Molecular Genetics and Physiology of PlantsFaculty of Biology and BiotechnologyUniversitätsstraße 150Bochum44801Germany
| | - Gruson Klaasse
- Department of Chemical Biology & Drug DiscoveryUtrecht Institute for Pharmaceutical SciencesUniversity UtrechtUniversiteitsweg 99Utrecht3584 CGthe Netherlands
| | - Judith K. Paulus
- Plant Chemetics LaboratoryDepartment of Plant SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3RBUK
| | - Daniel Krahn
- Plant Chemetics LaboratoryDepartment of Plant SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3RBUK
| | - Sabrina Ninck
- Chemische BiologieZentrum für Medizinische BiotechnologieFakultät für BiologieUniversität Duisburg‐EssenUniversitätsstr. 2Essen45117Germany
| | - Farnusch Kaschani
- Chemische BiologieZentrum für Medizinische BiotechnologieFakultät für BiologieUniversität Duisburg‐EssenUniversitätsstr. 2Essen45117Germany
| | - Markus Kaiser
- Chemische BiologieZentrum für Medizinische BiotechnologieFakultät für BiologieUniversität Duisburg‐EssenUniversitätsstr. 2Essen45117Germany
| | - Ondřej Novák
- Umeå Plant Science CentreDepartment of Forest Genetics and Plant PhysiologySwedish University of Agricultural SciencesUmeaSE‐901 83Sweden
- Laboratory of Growth RegulatorsThe Czech Academy of Sciences & Faculty of ScienceInstitute of Experimental BotanyPalacký UniversityŠlechtitelů 27Olomouc78371Czech Republic
| | - Karin Ljung
- Umeå Plant Science CentreDepartment of Forest Genetics and Plant PhysiologySwedish University of Agricultural SciencesUmeaSE‐901 83Sweden
| | - Suzanne Bulder
- Bejo Zaden B.V.Trambaan 1Warmenhuizen1749 CZthe Netherlands
| | - Marcel van Verk
- Plant‐Microbe InteractionsInstitute of Environmental BiologyUtrecht UniversityPadualaan 8Utrecht3584 CHthe Netherlands
- KeygeneAgro Business Park 90Wageningen6708 PWthe Netherlands
- Theoretical Biology and BioinformaticsInstitute of Biodynamics and BiocomplexityUtrecht UniversityPadualaan 8Utrecht3584 CHthe Netherlands
| | - Basten L. Snoek
- Theoretical Biology and BioinformaticsInstitute of Biodynamics and BiocomplexityUtrecht UniversityPadualaan 8Utrecht3584 CHthe Netherlands
| | - Martijn Fiers
- BioscienceWageningen University and ResearchDroevendaalsesteeg 1Wageningen6708 PBthe Netherlands
| | - Nathaniel I. Martin
- Department of Chemical Biology & Drug DiscoveryUtrecht Institute for Pharmaceutical SciencesUniversity UtrechtUniversiteitsweg 99Utrecht3584 CGthe Netherlands
- Biological Chemistry GroupSylvius LaboratoriesInstitute of Biology LeidenLeiden UniversitySylviusweg 72Leiden2333 BEthe Netherlands
| | - Renier A. L. van der Hoorn
- Plant Chemetics LaboratoryDepartment of Plant SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3RBUK
| | - Stéphanie Robert
- Umeå Plant Science CentreDepartment of Forest Genetics and Plant PhysiologySwedish University of Agricultural SciencesUmeaSE‐901 83Sweden
| | - Sjef Smeekens
- Molecular Plant PhysiologyInstitute of Environmental BiologyUtrecht UniversityPadualaan 8Utrecht3584 CHthe Netherlands
| | - Martijn van Zanten
- Molecular Plant PhysiologyInstitute of Environmental BiologyUtrecht UniversityPadualaan 8Utrecht3584 CHthe Netherlands
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13
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Zhang H, Xie P, Xu X, Xie Q, Yu F. Heterotrimeric G protein signalling in plant biotic and abiotic stress response. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23 Suppl 1:20-30. [PMID: 33533569 DOI: 10.1111/plb.13241] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 01/25/2021] [Indexed: 05/20/2023]
Abstract
Heterotrimeric G proteins act as molecular switches to participate in transmitting various stimuli signals from outside of cells. G proteins have three subunits, Gα, Gβ and Gγ, which function mutually to modulate many biological processes in plants, including plant growth and development, as well as biotic and abiotic stress responses. In plants, the number of Gγ subunits is larger than that of the α and β subunits. Based on recent breakthroughs in studies of plant G protein signal perception, transduction and downstream effectors, this review summarizes and analyses the connections between different subunits and the interactions of G proteins with other signalling pathways, especially in plant biotic and abiotic stress responses. Based on current progress and unresolved questions in the field, we also suggest future research directions on G proteins in plants.
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Affiliation(s)
- H Zhang
- School of Agriculture, Ningxia University, Yinchuan, China
| | - P Xie
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - X Xu
- School of Agriculture, Ningxia University, Yinchuan, China
- Breeding Base of State Key Laboratory of Land Degradation and Ecological Restoration of North Western China, Ningxia University, Yinchuan, China
| | - Q Xie
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - F Yu
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
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14
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McFarlane HE, Mutwil-Anderwald D, Verbančič J, Picard KL, Gookin TE, Froehlich A, Chakravorty D, Trindade LM, Alonso JM, Assmann SM, Persson S. A G protein-coupled receptor-like module regulates cellulose synthase secretion from the endomembrane system in Arabidopsis. Dev Cell 2021; 56:1484-1497.e7. [PMID: 33878345 DOI: 10.1016/j.devcel.2021.03.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 12/16/2020] [Accepted: 03/29/2021] [Indexed: 01/18/2023]
Abstract
Cellulose is produced at the plasma membrane of plant cells by cellulose synthase (CESA) complexes (CSCs). CSCs are assembled in the endomembrane system and then trafficked to the plasma membrane. Because CESAs are only active in the plasma membrane, control of CSC secretion regulates cellulose synthesis. We identified members of a family of seven transmembrane domain-containing proteins (7TMs) that are important for cellulose production during cell wall integrity stress. 7TMs are often associated with guanine nucleotide-binding (G) protein signaling and we found that mutants affecting the Gβγ dimer phenocopied the 7tm mutants. Unexpectedly, the 7TMs localized to the Golgi/trans-Golgi network where they interacted with G protein components. Here, the 7TMs and Gβγ regulated CESA trafficking but did not affect general protein secretion. Our results outline how a G protein-coupled module regulates CESA trafficking and reveal that defects in this process lead to exacerbated responses to cell wall integrity stress.
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Affiliation(s)
- Heather E McFarlane
- School of Biosciences, University of Melbourne, Parkville 3010 VIC, Australia; Max-Planck Institute for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany; Department of Cell and Systems Biology, University of Toronto, 25 Harbord St, Toronto, ON M5S 3G5, Canada.
| | - Daniela Mutwil-Anderwald
- Max-Planck Institute for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany; School of the Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Jana Verbančič
- School of Biosciences, University of Melbourne, Parkville 3010 VIC, Australia; Max-Planck Institute for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany
| | - Kelsey L Picard
- School of Biosciences, University of Melbourne, Parkville 3010 VIC, Australia; School of Natural Sciences, University of Tasmania, Hobart 7001 TAS, Australia
| | - Timothy E Gookin
- Department of Biology, The Pennsylvania State University, Mueller Laboratory, University Park, PA 16802, USA
| | - Anja Froehlich
- Max-Planck Institute for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany
| | - David Chakravorty
- Department of Biology, The Pennsylvania State University, Mueller Laboratory, University Park, PA 16802, USA
| | - Luisa M Trindade
- Plant Breeding, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands
| | - Jose M Alonso
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, NC 27695-7614, USA
| | - Sarah M Assmann
- Department of Biology, The Pennsylvania State University, Mueller Laboratory, University Park, PA 16802, USA
| | - Staffan Persson
- School of Biosciences, University of Melbourne, Parkville 3010 VIC, Australia; Max-Planck Institute for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany; Department of Plant & Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark; Copenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark; Joint International Research Laboratory of Metabolic & Developmental Sciences, State Key Laboratory of Hybrid Rice, SJTU-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
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15
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Yan C, Cannon AE, Watkins J, Keereetaweep J, Khan BR, Jones AM, Blancaflor EB, Azad RK, Chapman KD. Seedling Chloroplast Responses Induced by N-Linolenoylethanolamine Require Intact G-Protein Complexes. PLANT PHYSIOLOGY 2020; 184:459-477. [PMID: 32665332 PMCID: PMC7479873 DOI: 10.1104/pp.19.01552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 07/05/2020] [Indexed: 05/10/2023]
Abstract
In animals, several long-chain N-acylethanolamines (NAEs) have been identified as endocannabinoids and are autocrine signals that operate through cell surface G-protein-coupled cannabinoid receptors. Despite the occurrence of NAEs in land plants, including nonvascular plants, their precise signaling properties and molecular targets are not well defined. Here we show that the activity of N-linolenoylethanolamine (NAE 18:3) requires an intact G-protein complex. Specifically, genetic ablation of the Gβγ dimer or loss of the full set of atypical Gα subunits strongly attenuates an NAE-18:3-induced degreening of cotyledons in Arabidopsis (Arabidopsis thaliana) seedlings. This effect involves, at least in part, transcriptional regulation of chlorophyll biosynthesis and catabolism genes. In addition, there is feedforward transcriptional control of G-protein signaling components and G-protein interactors. These results are consistent with NAE 18:3 being a lipid signaling molecule in plants with a requirement for G-proteins to mediate signal transduction, a situation similar, but not identical, to the action of NAE endocannabinoids in animal systems.
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Affiliation(s)
- Chengshi Yan
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, Texas 76203
| | - Ashley E Cannon
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, Texas 76203
| | - Justin Watkins
- Departments of Biology, and Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Jantana Keereetaweep
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, Texas 76203
| | | | - Alan M Jones
- Departments of Biology, and Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | | | - Rajeev K Azad
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, Texas 76203
- Noble Research Institute LLC, Ardmore, Oklahoma 73401
- Department of Mathematics, University of North Texas, Denton, Texas 76203
| | - Kent D Chapman
- Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, Texas 76203
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16
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Guo X, Li J, Zhang L, Zhang Z, He P, Wang W, Wang M, Wang A, Zhu J. Heterotrimeric G-protein α subunit (LeGPA1) confers cold stress tolerance to processing tomato plants (Lycopersicon esculentum Mill). BMC PLANT BIOLOGY 2020; 20:394. [PMID: 32847511 PMCID: PMC7448358 DOI: 10.1186/s12870-020-02615-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 08/19/2020] [Indexed: 06/02/2023]
Abstract
BACKGROUND Tomatoes (Lycopersicon esculentum Mill) are key foods, and their molecular biology and evolution have been well described. Tomato plants originated in the tropics and, thus, are cold sensitive. RESULTS Here, we generated LeGPA1 overexpressing and RNA-interference (RNAi) transgenic tomato plants, which we then used to investigate the function of LeGPA1 in response to cold stress. Functional LeGPA1 was detected at the plasma membrane, and endogenous LeGPA1 was highly expressed in the roots and leaves. Cold treatment positively induced the expression of LeGPA1. Overexpression of LeGPA1 conferred tolerance to cold conditions and regulated the expression of genes related to the INDUCER OF CBF EXPRESSION-C-REPEAT-BINDING FACTOR (ICE-CBF) pathway in tomato plants. In the LeGPA1-overexpressing transgenic plants, the superoxide dismutase, peroxidase, and catalase activities and soluble sugar and proline contents were increased, and the production of reactive oxygen species and membrane lipid peroxidation decreased under cold stress. CONCLUSIONS Our findings suggest that improvements in antioxidant systems can help plants cope with the oxidative damage caused by cold stress, thereby stabilizing cell membrane structures and increasing the rate of photosynthesis. The data presented here provide evidence for the key role of LeGPA1 in mediating cold signal transduction in plant cells. These findings extend our knowledge of the roles of G-proteins in plants and help to clarify the mechanisms through which growth and development are regulated in processing tomato plants.
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Affiliation(s)
- Xinyong Guo
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Juju Li
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Li Zhang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Zhanwen Zhang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Ping He
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Wenwen Wang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Mei Wang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Aiying Wang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Jianbo Zhu
- College of Life Science, Shihezi University, Shihezi, 832000, China.
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17
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Xue J, Gong BQ, Yao X, Huang X, Li JF. BAK1-mediated phosphorylation of canonical G protein alpha during flagellin signaling in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:690-701. [PMID: 31087771 DOI: 10.1111/jipb.12824] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 05/04/2019] [Indexed: 05/09/2023]
Abstract
Heterotrimeric G proteins consisting of Gα, Gβ and Gγ are conserved signaling hubs in eukaryotes. Without analogs to canonical animal G protein-coupled receptors, plant cells are thought to use RGS1 and a yet unknown mechanism to regulate the activity of Gα. Meanwhile, the exact role of canonical Gα in plant innate immunity remains controversial. Here, we report multiple immune deficiencies in the null allele of Arabidopsis Gα (GPA1) in response to bacterial flg22 elicitor, clarifying a positive regulatory role of GPA1 in flg22 signaling. We also detect overall increased phosphorylation of GPA1 but reduced phosphorylation at Thr19 upon flg22 elicitation. Interestingly, flg22 could not induce phosphorylation of GPA1T19A and GPA1T19D , suggesting that the dynamic Thr19 phosphorylation is required for GPA1 to respond to flg22. Moreover, flg22-induced GPA1 phosphorylation is largely abolished in the absence of BAK1 in vivo, and BAK1 could phosphorylate GPA1 but not GPA1T19A in vitro at the phosphorylation sites identified in vivo, suggesting BAK1 is likely the kinase for GPA1 phosphorylation in response to flg22. Furthermore, the T19A mutation could promote flg22-induced association, rather than dissociation, between GPA1 and RGS1. Taken together, our findings shed new insights into the function and regulation of GPA1 in Arabidopsis defense signaling.
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Affiliation(s)
- Jiao Xue
- Guangdong Provincial Key Laboratory of Plant Resources, State Key Laboratory of Biocontrol, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Ben-Qiang Gong
- Guangdong Provincial Key Laboratory of Plant Resources, State Key Laboratory of Biocontrol, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Xinran Yao
- Guangdong Provincial Key Laboratory of Plant Resources, State Key Laboratory of Biocontrol, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Xiangjuan Huang
- Guangdong Provincial Key Laboratory of Plant Resources, State Key Laboratory of Biocontrol, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Jian-Feng Li
- Guangdong Provincial Key Laboratory of Plant Resources, State Key Laboratory of Biocontrol, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
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18
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Abstract
Cryptochromes are blue-light receptors that mediate photoresponses in plants. The genomes of most land plants encode two clades of cryptochromes, CRY1 and CRY2, which mediate distinct and overlapping photoresponses within the same species and between different plant species. Photoresponsive protein-protein interaction is the primary mode of signal transduction of cryptochromes. Cryptochromes exist as physiologically inactive monomers in the dark; the absorption of photons leads to conformational change and cryptochrome homooligomerization, which alters the affinity of cryptochromes interacting with cryptochrome-interacting proteins to form various cryptochrome complexes. These cryptochrome complexes, collectively referred to as the cryptochrome complexome, regulate transcription or stability of photoresponsive proteins to modulate plant growth and development. The activity of cryptochromes is regulated by photooligomerization; dark monomerization; cryptochrome regulatory proteins; and cryptochrome phosphorylation, ubiquitination, and degradation. Most of the more than 30 presently known cryptochrome-interacting proteins are either regulated by other photoreceptors or physically interactingwith the protein complexes of other photoreceptors. Some cryptochrome-interacting proteins are also hormonal signaling or regulatory proteins. These two mechanisms enable cryptochromes to integrate blue-light signals with other internal and external signals to optimize plant growth and development.
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Affiliation(s)
- Qin Wang
- Basic Forestry and Proteomics Research Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chentao Lin
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095, USA;
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19
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Roy Choudhury S, Li M, Lee V, Nandety RS, Mysore KS, Pandey S. Flexible functional interactions between G-protein subunits contribute to the specificity of plant responses. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:207-221. [PMID: 32034949 DOI: 10.1111/tpj.14714] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 01/17/2020] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
Plants being sessile integrate information from a variety of endogenous and external cues simultaneously to optimize growth and development. This necessitates the signaling networks in plants to be highly dynamic and flexible. One such network involves heterotrimeric G-proteins comprised of Gα, Gβ, and Gγ subunits, which influence many aspects of growth, development, and stress response pathways. In plants such as Arabidopsis, a relatively simple repertoire of G-proteins comprised of one canonical and three extra-large Gα, one Gβ and three Gγ subunits exists. Because the Gβ and Gγ proteins form obligate dimers, the phenotypes of plants lacking the sole Gβ or all Gγ genes are similar, as expected. However, Gα proteins can exist either as monomers or in a complex with Gβγ, and the details of combinatorial genetic and physiological interactions of different Gα proteins with the sole Gβ remain unexplored. To evaluate such flexible, signal-dependent interactions and their contribution toward eliciting a specific response, we have generated Arabidopsis mutants lacking specific combinations of Gα and Gβ genes, performed extensive phenotypic analysis, and evaluated the results in the context of subunit usage and interaction specificity. Our data show that multiple mechanistic modes, and in some cases complex epistatic relationships, exist depending on the signal-dependent interactions between the Gα and Gβ proteins. This suggests that, despite their limited numbers, the inherent flexibility of plant G-protein networks provides for the adaptability needed to survive under continuously changing environments.
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Affiliation(s)
| | - Mao Li
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
| | - Veronica Lee
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
| | | | | | - Sona Pandey
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
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20
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Maruta N, Trusov Y, Chakravorty D, Urano D, Assmann SM, Botella JR. Nucleotide exchange-dependent and nucleotide exchange-independent functions of plant heterotrimeric GTP-binding proteins. Sci Signal 2019; 12:12/606/eaav9526. [PMID: 31690635 DOI: 10.1126/scisignal.aav9526] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins), which are composed of α, β, and γ subunits, are versatile, guanine nucleotide-dependent, molecular on-off switches. In animals and fungi, the exchange of GDP for GTP on Gα controls G protein activation and is crucial for normal cellular responses to diverse extracellular signals. The model plant Arabidopsis thaliana has a single canonical Gα subunit, AtGPA1. We found that, in planta, the constitutively active, GTP-bound AtGPA1(Q222L) mutant and the nucleotide-free AtGPA1(S52C) mutant interacted with Gβγ1 and Gβγ2 dimers with similar affinities, suggesting that G protein heterotrimer formation occurred independently of nucleotide exchange. In contrast, AtGPA1(Q222L) had a greater affinity than that of AtGPA1(S52C) for Gβγ3, suggesting that the GTP-bound conformation of AtGPA1(Q222L) is distinct and tightly associated with Gβγ3. Functional analysis of transgenic lines expressing either AtGPA1(S52C) or AtGPA1(Q222L) in the gpa1-null mutant background revealed various mutant phenotypes that were complemented by either AtGPA1(S52C) or AtGPA1(Q222L). We conclude that, in addition to the canonical GDP-GTP exchange-dependent mechanism, plant G proteins can function independently of nucleotide exchange.
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Affiliation(s)
- Natsumi Maruta
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Yuri Trusov
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - David Chakravorty
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Daisuke Urano
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore
| | - Sarah M Assmann
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Jose R Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD 4072, Australia. .,State Key Laboratory of Cotton Biology, Department of Biology, Institute of Plant Stress Biology, Henan University, Kaifeng 475001, China
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21
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Jeon BW, Acharya BR, Assmann SM. The Arabidopsis heterotrimeric G-protein β subunit, AGB1, is required for guard cell calcium sensing and calcium-induced calcium release. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 99:231-244. [PMID: 30882980 DOI: 10.1111/tpj.14318] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 03/04/2019] [Accepted: 03/13/2019] [Indexed: 05/08/2023]
Abstract
Cytosolic calcium concentration ([Ca2+ ]cyt ) and heterotrimeric G-proteins are universal eukaryotic signaling elements. In plant guard cells, extracellular calcium (Cao ) is as strong a stimulus for stomatal closure as the phytohormone abscisic acid (ABA), but underlying mechanisms remain elusive. Here, we report that the sole Arabidopsis heterotrimeric Gβ subunit, AGB1, is required for four guard cell Cao responses: induction of stomatal closure; inhibition of stomatal opening; [Ca2+ ]cyt oscillation; and inositol 1,4,5-trisphosphate (InsP3) production. Stomata in wild-type Arabidopsis (Col) and in mutants of the canonical Gα subunit, GPA1, showed inhibition of stomatal opening and promotion of stomatal closure by Cao . By contrast, stomatal movements of agb1 mutants and agb1/gpa1 double-mutants, as well as those of the agg1agg2 Gγ double-mutant, were insensitive to Cao . These behaviors contrast with ABA-regulated stomatal movements, which involve GPA1 and AGB1/AGG3 dimers, illustrating differential partitioning of G-protein subunits among stimuli with similar ultimate impacts, which may facilitate stimulus-specific encoding. AGB1 knockouts retained reactive oxygen species and NO production, but lost YC3.6-detected [Ca2+ ]cyt oscillations in response to Cao , initiating only a single [Ca2+ ]cyt spike. Experimentally imposed [Ca2+ ]cyt oscillations restored stomatal closure in agb1. Yeast two-hybrid and bimolecular complementation fluorescence experiments revealed that AGB1 interacts with phospholipase Cs (PLCs), and Cao induced InsP3 production in Col but not in agb1. In sum, G-protein signaling via AGB1/AGG1/AGG2 is essential for Cao -regulation of stomatal apertures, and stomatal movements in response to Cao apparently require Ca2+ -induced Ca2+ release that is likely dependent on Gβγ interaction with PLCs leading to InsP3 production.
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Affiliation(s)
- Byeong Wook Jeon
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, 61186, Korea
| | - Biswa R Acharya
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Sarah M Assmann
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
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22
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Miao J, Yang Z, Zhang D, Wang Y, Xu M, Zhou L, Wang J, Wu S, Yao Y, Du X, Gu F, Gong Z, Gu M, Liang G, Zhou Y. Mutation of RGG2, which encodes a type B heterotrimeric G protein γ subunit, increases grain size and yield production in rice. PLANT BIOTECHNOLOGY JOURNAL 2019; 17:650-664. [PMID: 30160362 PMCID: PMC6381795 DOI: 10.1111/pbi.13005] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 08/20/2018] [Accepted: 08/23/2018] [Indexed: 05/22/2023]
Abstract
Heterotrimeric G proteins, which consist of Gα , Gβ and Gγ subunits, function as molecular switches that regulate a wide range of developmental processes in plants. In this study, we characterised the function of rice RGG2, which encodes a type B Gγ subunit, in regulating grain size and yield production. The expression levels of RGG2 were significantly higher than those of other rice Gγ -encoding genes in all tissues tested, suggesting that RGG2 plays essential roles in rice growth and development. By regulating cell expansion, overexpression of RGG2 in Nipponbare (NIP) led to reduced plant height and decreased grain size. By contrast, two mutants generated by the clustered, regularly interspaced, short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system in the Zhenshan 97 (ZS97) background, zrgg2-1 and zrgg2-2, exhibited enhanced growth, including elongated internodes, increased 1000-grain weight and plant biomass and enhanced grain yield per plant (+11.8% and 16.0%, respectively). These results demonstrate that RGG2 acts as a negative regulator of plant growth and organ size in rice. By measuring the length of the second leaf sheath after gibberellin (GA3 ) treatment and the GA-induced α-amylase activity of seeds, we found that RGG2 is also involved in GA signalling. In summary, we propose that RGG2 may regulate grain and organ size via the GA pathway and that manipulation of RGG2 may provide a novel strategy for rice grain yield enhancement.
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Affiliation(s)
- Jun Miao
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Zefeng Yang
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Dongping Zhang
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Yuzhu Wang
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Mengbin Xu
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Lihui Zhou
- Institute of Food CropsJiangsu Academy of Agricultural SciencesNanjingChina
| | - Jun Wang
- Institute of Food CropsJiangsu Academy of Agricultural SciencesNanjingChina
| | - Shujun Wu
- Shanghai Academy of Agricultural SciencesShanghaiChina
| | - Youli Yao
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Xi Du
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Fangfei Gu
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Zhiyun Gong
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Minghong Gu
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Guohua Liang
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Yong Zhou
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
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23
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Lian H, Xu P, He S, Wu J, Pan J, Wang W, Xu F, Wang S, Pan J, Huang J, Yang HQ. Photoexcited CRYPTOCHROME 1 Interacts Directly with G-Protein β Subunit AGB1 to Regulate the DNA-Binding Activity of HY5 and Photomorphogenesis in Arabidopsis. MOLECULAR PLANT 2018; 11:1248-1263. [PMID: 30176372 DOI: 10.1016/j.molp.2018.08.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/25/2018] [Accepted: 08/23/2018] [Indexed: 05/25/2023]
Abstract
Light and the heterotrimeric G-protein are known to antagonistically regulate photomorphogenesis in Arabidopsis. However, whether light and G-protein coordinate the regulation of photomorphogenesis is largely unknown. Here we show that the blue light photoreceptor cryptochrome 1 (CRY1) physically interacts with the G-protein β subunit, AGB1, in a blue light-dependent manner. We also show that AGB1 directly interacts with HY5, a basic leucine zipper transcriptional factor that acts as a critical positive regulator of photomorphogenesis, to inhibit its DNA-binding activity. Genetic studies suggest that CRY1 acts partially through AGB1, and AGB1 acts partially through HY5 to regulate photomorphogenesis. Moreover, we demonstrate that blue light-triggered interaction of CRY1 with AGB1 promotes the dissociation of HY5 from AGB1. Our results suggest that the CRY1 signaling mechanism involves positive regulation of the DNA-binding activity of HY5 mediated by the CRY1-AGB1 interaction, which inhibits the association of AGB1 with HY5. We propose that the antagonistic regulation of HY5 DNA-binding activity by CRY1 and AGB1 may allow plants to balance light and G-protein signaling and optimize photomorphogenesis.
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Affiliation(s)
- Hongli Lian
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pengbo Xu
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shengbo He
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jun Wu
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jian Pan
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wenxiu Wang
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Feng Xu
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Sheng Wang
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Junsong Pan
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jirong Huang
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Hong-Quan Yang
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China.
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24
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Liang Y, Zhao X, Jones AM, Gao Y. G proteins sculp root architecture in response to nitrogen in rice and Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 274:129-136. [PMID: 30080596 DOI: 10.1016/j.plantsci.2018.05.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/19/2018] [Accepted: 05/21/2018] [Indexed: 05/20/2023]
Abstract
Nitrogen is a key nutrient for plant growth and development. Plants regulate nitrogen availability and uptake efficiency through controlling root architecture. While the heterotrimeric G protein complex is an important element to regulate root morphology, it remains unknown whether the G protein regulates the root architecture in response to nitrogen supply. We used rice and Arabidopsis G protein mutants to study the root architecture in response to different nitrogen concentrations. We found that nitrogen inhibits root horizontal projection area (network area), root perimeter, total length, but not root diameter (average root width). Nitrogen influenced bushiness and root spatial distribution by inhibiting horizontal growth and promoting vertical expansion. The dynamic changes of the rice G protein mutant DK22 at different concentrations of nitrogen from day 7 to day 9 were different from the wild type with regard to bushiness and spatial distribution. The agb1-2 mutant in Arabidopsis lacked the inhibitory effect of nitrate on root growth. The heterotrimeric G protein complex regulates the inhibitory effect on root growth caused by high nitrogen supply and root spatial distribution in response to different nitrogen concentrations.
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Affiliation(s)
- Ying Liang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, 27599-3280, USA
| | - Xiaoyu Zhao
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Alan M Jones
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, 27599-3280, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, 27599-3280, USA
| | - Yajun Gao
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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25
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Yu Y, Chakravorty D, Assmann SM. The G Protein β-Subunit, AGB1, Interacts with FERONIA in RALF1-Regulated Stomatal Movement. PLANT PHYSIOLOGY 2018; 176:2426-2440. [PMID: 29301953 PMCID: PMC5841690 DOI: 10.1104/pp.17.01277] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 01/03/2018] [Indexed: 05/04/2023]
Abstract
Heterotrimeric guanine nucleotide-binding (G) proteins are composed of Gα, Gβ, and Gγ subunits and function as molecular switches in signal transduction. In Arabidopsis (Arabidopsis thaliana), there are one canonical Gα (GPA1), three extra-large Gα (XLG1, XLG2, and XLG3), one Gβ (AGB1), and three Gγ (AGG1, AGG2, and AGG3) subunits. To elucidate AGB1 molecular signaling, we performed immunoprecipitation using plasma membrane-enriched proteins followed by mass spectrometry to identify the protein interactors of AGB1. After eliminating proteins present in the control immunoprecipitation, commonly identified contaminants, and organellar proteins, a total of 103 candidate AGB1-associated proteins were confidently identified. We identified all of the G protein subunits except XLG1, receptor-like kinases, Ca2+ signaling-related proteins, and 14-3-3-like proteins, all of which may couple with or modulate G protein signaling. We confirmed physical interaction between AGB1 and the receptor-like kinase FERONIA (FER) using bimolecular fluorescence complementation. The Rapid Alkalinization Factor (RALF) family of polypeptides have been shown to be ligands of FER. In this study, we demonstrate that RALF1 regulates stomatal apertures and does so in a G protein-dependent manner, inhibiting stomatal opening and promoting stomatal closure in Columbia but not in agb1 mutants. We further show that AGGs and XLGs, but not GPA1, participate in RALF1-mediated stomatal signaling. Our results suggest that FER acts as a G protein-coupled receptor for plant heterotrimeric G proteins.
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Affiliation(s)
- Yunqing Yu
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - David Chakravorty
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Sarah M Assmann
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
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26
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Ferrero-Serrano Á, Su Z, Assmann SM. Illuminating the role of the Gα heterotrimeric G protein subunit, RGA1, in regulating photoprotection and photoavoidance in rice. PLANT, CELL & ENVIRONMENT 2018; 41:451-468. [PMID: 29216416 DOI: 10.1111/pce.13113] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/19/2017] [Accepted: 11/21/2017] [Indexed: 05/22/2023]
Abstract
We studied physiological mechanisms of photoavoidance and photoprotection of a dwarf rice mutant with erect leaves, d1, in which the RGA1 gene, which encodes the Gα subunit of the heterotrimeric G protein, is non-functional. Leaves of d1 exhibit lower leaf temperature and higher photochemical reflectance index relative to wild type (WT), indicative of increased photoavoidance and more efficient light harvesting. RNA sequencing analysis of flag leaves revealed that messenger RNA levels of genes encoding heat shock proteins, enzymes associated with chlorophyll breakdown, and ROS scavengers were down-regulated in d1. By contrast, genes encoding proteins associated with light harvesting, Photosystem II, cyclic electron transport, Photosystem I, and chlorophyll biosynthesis were up-regulated in d1. Consistent with these observations, when WT and d1 plants were experimentally subjected to the same light intensity, d1 plants exhibited a greater capacity to dissipate excess irradiance (increased nonphotochemical quenching) relative to WT. The increased capacity in d1 for both photoavoidance and photoprotection reduced sustained photoinhibitory damage, as revealed by a higher Fv /Fm . We therefore propose RGA1 as a regulator of photoavoidance and photoprotection mechanisms in rice and highlight the prospect of exploiting modulation of heterotrimeric G protein signalling to increase these characteristics and improve the yield of cereals in the event of abiotic stress.
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Affiliation(s)
- Ángel Ferrero-Serrano
- Biology Department, Penn State University, 208 Mueller Laboratory, University Park, PA, 16802, USA
| | - Zhao Su
- Biology Department, Penn State University, 208 Mueller Laboratory, University Park, PA, 16802, USA
| | - Sarah M Assmann
- Biology Department, Penn State University, 208 Mueller Laboratory, University Park, PA, 16802, USA
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27
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Xu DB, Gao SQ, Ma YN, Wang XT, Feng L, Li LC, Xu ZS, Chen YF, Chen M, Ma YZ. The G-Protein β Subunit AGB1 Promotes Hypocotyl Elongation through Inhibiting Transcription Activation Function of BBX21 in Arabidopsis. MOLECULAR PLANT 2017; 10:1206-1223. [PMID: 28827171 DOI: 10.1016/j.molp.2017.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 05/10/2023]
Abstract
Hypocotyl development in Arabidopsis thaliana is regulated by light and endogenous hormonal cues, making it an ideal model to study the interplay between light and endogenous growth regulators. BBX21, a B-box (BBX)-like zinc-finger transcription factor, integrates light and abscisic acid signals to regulate hypocotyl elongation in Arabidopsis. Heterotrimeric G-proteins are pivotal regulators of plant development. The short hypocotyl phenotype of the G-protein β-subunit (AGB1) mutant (agb1-2) has been previously identified, but the precise role of AGB1 in hypocotyl elongation remains enigmatic. Here, we show that AGB1 directly interacts with BBX21, and the short hypocotyl phenotype of agb1-2 is partially suppressed in agb1-2bbx21-1 double mutant. BBX21 functions in the downstream of AGB1 and overexpression of BBX21 in agb1-2 causes a more pronounced reduction in hypocotyl length, indicating that AGB1 plays an oppositional role in relation to BBX21 during hypocotyl development. Furthermore, we demonstrate that the C-terminal region of BBX21 is important for both its intracellular localization and its transcriptional activation activity that is inhibited by interaction with AGB1. ChIP assays showed that BBX21 specifically associates with its own promoter and with those of BBX22, HY5, and GA2ox1. which is not altered in agb1-2. These data suggest that the AGB1-BBX21 interaction only affects the transcriptional activation activity of BBX21 but has no effect on its DNA binding ability. Taken together, our data demonstrate that AGB1 positively promotes hypocotyl elongation through repressing BBX21 activity.
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Affiliation(s)
- Dong-Bei Xu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China; Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, No.1 Qianhu Houcun, Zhongshanmen Wai, Nanjing, Jiangsu Province 210014, PR China
| | - Shi-Qing Gao
- Beijing Engineering Research Center for Hybrid Wheat, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
| | - Ya-Nan Ma
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiao-Ting Wang
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lu Feng
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lian-Cheng Li
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Zhao-Shi Xu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China
| | - Yao-Feng Chen
- College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - Ming Chen
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China.
| | - You-Zhi Ma
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS)/National Key Facility for Crop Gene Resources and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crops, Ministry of Agriculture, Beijing 100081, China.
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28
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Albert R, Acharya BR, Jeon BW, Zañudo JGT, Zhu M, Osman K, Assmann SM. A new discrete dynamic model of ABA-induced stomatal closure predicts key feedback loops. PLoS Biol 2017; 15:e2003451. [PMID: 28937978 PMCID: PMC5627951 DOI: 10.1371/journal.pbio.2003451] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 10/04/2017] [Accepted: 09/04/2017] [Indexed: 11/19/2022] Open
Abstract
Stomata, microscopic pores in leaf surfaces through which water loss and carbon dioxide uptake occur, are closed in response to drought by the phytohormone abscisic acid (ABA). This process is vital for drought tolerance and has been the topic of extensive experimental investigation in the last decades. Although a core signaling chain has been elucidated consisting of ABA binding to receptors, which alleviates negative regulation by protein phosphatases 2C (PP2Cs) of the protein kinase OPEN STOMATA 1 (OST1) and ultimately results in activation of anion channels, osmotic water loss, and stomatal closure, over 70 additional components have been identified, yet their relationships with each other and the core components are poorly elucidated. We integrated and processed hundreds of disparate observations regarding ABA signal transduction responses underlying stomatal closure into a network of 84 nodes and 156 edges and, as a result, established those relationships, including identification of a 36-node, strongly connected (feedback-rich) component as well as its in- and out-components. The network's domination by a feedback-rich component may reflect a general feature of rapid signaling events. We developed a discrete dynamic model of this network and elucidated the effects of ABA plus knockout or constitutive activity of 79 nodes on both the outcome of the system (closure) and the status of all internal nodes. The model, with more than 1024 system states, is far from fully determined by the available data, yet model results agree with existing experiments in 82 cases and disagree in only 17 cases, a validation rate of 75%. Our results reveal nodes that could be engineered to impact stomatal closure in a controlled fashion and also provide over 140 novel predictions for which experimental data are currently lacking. Noting the paucity of wet-bench data regarding combinatorial effects of ABA and internal node activation, we experimentally confirmed several predictions of the model with regard to reactive oxygen species, cytosolic Ca2+ (Ca2+c), and heterotrimeric G-protein signaling. We analyzed dynamics-determining positive and negative feedback loops, thereby elucidating the attractor (dynamic behavior) repertoire of the system and the groups of nodes that determine each attractor. Based on this analysis, we predict the likely presence of a previously unrecognized feedback mechanism dependent on Ca2+c. This mechanism would provide model agreement with 10 additional experimental observations, for a validation rate of 85%. Our research underscores the importance of feedback regulation in generating robust and adaptable biological responses. The high validation rate of our model illustrates the advantages of discrete dynamic modeling for complex, nonlinear systems common in biology.
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Affiliation(s)
- Réka Albert
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Biswa R. Acharya
- Biology Department, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Byeong Wook Jeon
- Biology Department, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jorge G. T. Zañudo
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Mengmeng Zhu
- Biology Department, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Karim Osman
- Biology Department, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Sarah M. Assmann
- Biology Department, Pennsylvania State University, University Park, Pennsylvania, United States of America
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29
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Liang Y, Gao Y, Jones AM. Extra Large G-Protein Interactome Reveals Multiple Stress Response Function and Partner-Dependent XLG Subcellular Localization. FRONTIERS IN PLANT SCIENCE 2017; 8:1015. [PMID: 28659958 PMCID: PMC5469152 DOI: 10.3389/fpls.2017.01015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 05/26/2017] [Indexed: 05/09/2023]
Abstract
The three-member family of Arabidopsis extra-large G proteins (XLG1-3) defines the prototype of an atypical Gα subunit in the heterotrimeric G protein complex. Recent evidence indicate that XLG subunits operate along with its Gβγ dimer in root morphology, stress responsiveness, and cytokinin induced development, however downstream targets of activated XLG proteins in the stress pathways are rarely known. To assemble a set of candidate XLG-targeted proteins, a yeast two-hybrid complementation-based screen was performed using XLG protein baits to query interactions between XLG and partner protein found in glucose-treated seedlings, roots, and Arabidopsis cells in culture. Seventy two interactors were identified and >60% of a test set displayed in vivo interaction with XLG proteins. Gene co-expression analysis shows that >70% of the interactors are positively correlated with the corresponding XLG partners. Gene Ontology enrichment for all the candidates indicates stress responses and posits a molecular mechanism involving a specific set of transcription factor partners to XLG. Genes encoding two of these transcription factors, SZF1 and 2, require XLG proteins for full NaCl-induced expression. The subcellular localization of the XLG proteins in the nucleus, endosome, and plasma membrane is dependent on the specific interacting partner.
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Affiliation(s)
- Ying Liang
- College of Natural Resources and Environment, Northwest A&F UniversityXianyang, China
- Department of Biology University of North Carolina at Chapel HillChapel Hill, NC, United States
| | - Yajun Gao
- College of Natural Resources and Environment, Northwest A&F UniversityXianyang, China
- *Correspondence: Yajun Gao
| | - Alan M. Jones
- Department of Biology University of North Carolina at Chapel HillChapel Hill, NC, United States
- Department of Pharmacology, University of North Carolina at Chapel HillChapel Hill, NC, United States
- Alan M. Jones
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Liang Y, Urano D, Liao KL, Hedrick TL, Gao Y, Jones AM. A nondestructive method to estimate the chlorophyll content of Arabidopsis seedlings. PLANT METHODS 2017; 13:26. [PMID: 28416964 PMCID: PMC5391588 DOI: 10.1186/s13007-017-0174-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 03/30/2017] [Indexed: 05/20/2023]
Abstract
BACKGROUND Chlorophyll content decreases in plants under stress conditions, therefore it is used commonly as an indicator of plant health. Arabidopsis thaliana offers a convenient and fast way to test physiological phenotypes of mutations and treatments. However, chlorophyll measurements with conventional solvent extraction are not applicable to Arabidopsis leaves due to their small size, especially when grown on culture dishes. RESULTS We provide a nondestructive method for chlorophyll measurement whereby the red, green and blue (RGB) values of a color leaf image is used to estimate the chlorophyll content from Arabidopsis leaves. The method accommodates different profiles of digital cameras by incorporating the ColorChecker chart to make the digital negative profiles, to adjust the white balance, and to calibrate the exposure rate differences caused by the environment so that this method is applicable in any environment. We chose an exponential function model to estimate chlorophyll content from the RGB values, and fitted the model parameters with physical measurements of chlorophyll contents. As proof of utility, this method was used to estimate chlorophyll content of G protein mutants grown on different sugar to nitrogen ratios. CONCLUSION This method is a simple, fast, inexpensive, and nondestructive estimation of chlorophyll content of Arabidopsis seedlings. This method lead to the discovery that G proteins are important in sensing the C/N balance to control chlorophyll content in Arabidopsis.
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Affiliation(s)
- Ying Liang
- Department of Biology, The University of North Carolina at Chapel Hill, Coker Hall, CB#3280, Chapel Hill, NC 27599-3280 USA
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Daisuke Urano
- Department of Biology, The University of North Carolina at Chapel Hill, Coker Hall, CB#3280, Chapel Hill, NC 27599-3280 USA
| | - Kang-Ling Liao
- Department of Biology, The University of North Carolina at Chapel Hill, Coker Hall, CB#3280, Chapel Hill, NC 27599-3280 USA
| | - Tyson L. Hedrick
- Department of Biology, The University of North Carolina at Chapel Hill, Coker Hall, CB#3280, Chapel Hill, NC 27599-3280 USA
| | - Yajun Gao
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Alan M. Jones
- Department of Biology, The University of North Carolina at Chapel Hill, Coker Hall, CB#3280, Chapel Hill, NC 27599-3280 USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280 USA
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Ermert AL, Mailliet K, Hughes J. Holophytochrome-Interacting Proteins in Physcomitrella: Putative Actors in Phytochrome Cytoplasmic Signaling. FRONTIERS IN PLANT SCIENCE 2016; 7:613. [PMID: 27242820 PMCID: PMC4867686 DOI: 10.3389/fpls.2016.00613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 04/21/2016] [Indexed: 05/26/2023]
Abstract
Phytochromes are the principle photoreceptors in light-regulated plant development, primarily acting via translocation of the light-activated photoreceptor into the nucleus and subsequent gene regulation. However, several independent lines of evidence indicate unambiguously that an additional cytoplasmic signaling mechanism must exist. Directional responses in filament tip cells of the moss Physcomitrella patens are steered by phy4 which has been shown to interact physically with the blue light receptor phototropin at the plasma membrane. This complex might perceive and transduce vectorial information leading to cytoskeleton reorganization and finally a directional growth response. We developed yeast two-hybrid procedures using photochemically functional, full-length phy4 as bait in Physcomitrella cDNA library screens and growth assays under different light conditions, revealing Pfr-dependent interactions possibly associated with phytochrome cytoplasmic signaling. Candidate proteins were then expressed in planta with fluorescent protein tags to determine their intracellular localization in darkness and red light. Of 14 candidates, 12 were confirmed to interact with phy4 in planta using bimolecular fluorescence complementation. We also used database information to study their expression patterns relative to those of phy4. We discuss the likely functional characteristics of these holophytochrome-interacting proteins (HIP's) and their possible roles in signaling.
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Liang X, Ding P, Lian K, Wang J, Ma M, Li L, Li L, Li M, Zhang X, Chen S, Zhang Y, Zhou JM. Arabidopsis heterotrimeric G proteins regulate immunity by directly coupling to the FLS2 receptor. eLife 2016; 5:e13568. [PMID: 27043937 PMCID: PMC4846371 DOI: 10.7554/elife.13568] [Citation(s) in RCA: 185] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 04/02/2016] [Indexed: 12/19/2022] Open
Abstract
The Arabidopsis immune receptor FLS2 perceives bacterial flagellin epitope flg22 to activate defenses through the central cytoplasmic kinase BIK1. The heterotrimeric G proteins composed of the non-canonical Gα protein XLG2, the Gβ protein AGB1, and the Gγ proteins AGG1 and AGG2 are required for FLS2-mediated immune responses through an unknown mechanism. Here we show that in the pre-activation state, XLG2 directly interacts with FLS2 and BIK1, and it functions together with AGB1 and AGG1/2 to attenuate proteasome-mediated degradation of BIK1, allowing optimum immune activation. Following the activation by flg22, XLG2 dissociates from AGB1 and is phosphorylated by BIK1 in the N terminus. The phosphorylated XLG2 enhances the production of reactive oxygen species (ROS) likely by modulating the NADPH oxidase RbohD. The study demonstrates that the G proteins are directly coupled to the FLS2 receptor complex and regulate immune signaling through both pre-activation and post-activation mechanisms.
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Affiliation(s)
- Xiangxiu Liang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Pingtao Ding
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Kehui Lian
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Jinlong Wang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Miaomiao Ma
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Lin Li
- National Institute of Biological Sciences, Beijing, China
| | - Lei Li
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Meng Li
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xiaojuan Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - She Chen
- National Institute of Biological Sciences, Beijing, China
| | - Yuelin Zhang
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Jian-Min Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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Subramaniam G, Trusov Y, Lopez-Encina C, Hayashi S, Batley J, Botella JR. Type B Heterotrimeric G Protein γ-Subunit Regulates Auxin and ABA Signaling in Tomato. PLANT PHYSIOLOGY 2016; 170:1117-34. [PMID: 26668332 PMCID: PMC4734580 DOI: 10.1104/pp.15.01675] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/13/2015] [Indexed: 05/09/2023]
Abstract
Heterotrimeric G proteins composed of α, β, and γ subunits are central signal transducers mediating the cellular response to multiple stimuli in most eukaryotes. Gγ subunits provide proper cellular localization and functional specificity to the heterotrimer complex. Plant Gγ subunits, divided into three structurally distinct types, are more diverse than their animal counterparts. Type B Gγ subunits, lacking a carboxyl-terminal isoprenylation motif, are found only in flowering plants. We present the functional characterization of type B Gγ subunit (SlGGB1) in tomato (Solanum lycopersicum). We show that SlGGB1 is the most abundant Gγ subunit in tomato and strongly interacts with the Gβ subunit. Importantly, the green fluorescent protein-SlGGB1 fusion protein as well as the carboxyl-terminal yellow fluorescent protein-SlGGB1/amino-terminal yellow fluorescent protein-Gβ heterodimer were localized in the plasma membrane, nucleus, and cytoplasm. RNA interference-mediated silencing of SlGGB1 resulted in smaller seeds, higher number of lateral roots, and pointy fruits. The silenced lines were hypersensitive to exogenous auxin, while levels of endogenous auxins were lower or similar to those of the wild type. SlGGB1-silenced plants also showed strong hyposensitivity to abscisic acid (ABA) during seed germination but not in other related assays. Transcriptome analysis of the transgenic seeds revealed abnormal expression of genes involved in ABA sensing, signaling, and response. We conclude that the type B Gγ subunit SlGGB1 mediates auxin and ABA signaling in tomato.
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Affiliation(s)
- Gayathery Subramaniam
- Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.)
| | - Yuri Trusov
- Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.)
| | - Carlos Lopez-Encina
- Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.)
| | - Satomi Hayashi
- Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.)
| | - Jacqueline Batley
- Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.)
| | - José Ramón Botella
- Plant Genetic Engineering Laboratory (G.S., Y.T., J.R.B.) and Centre for Integrative Legume Research (S.H., J.B.), School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland 4072, Australia; andInstituto de Horticultura Subtropical y Mediterranea La Mayora, Consejo Superior de Investigaciones Científicas, Universidad de Malaga, Experimental Station La Mayora, 29750 Algarrobo-Costa, Malaga, Spain (C.L.-E.)
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Chakraborty N, Sharma P, Kanyuka K, Pathak RR, Choudhury D, Hooley R, Raghuram N. G-protein α-subunit (GPA1) regulates stress, nitrate and phosphate response, flavonoid biosynthesis, fruit/seed development and substantially shares GCR1 regulation in A. thaliana. PLANT MOLECULAR BIOLOGY 2015; 89:559-76. [PMID: 26346778 DOI: 10.1007/s11103-015-0374-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 08/28/2015] [Indexed: 05/09/2023]
Abstract
Heterotrimeric G-proteins are implicated in several plant processes, but the mechanisms of signal-response coupling and the roles of G-protein coupled receptors in general and GCR1 in particular, remain poorly understood. We isolated a knock-out mutant of the Arabidopsis G-protein α subunit (gpa1-5) and analysed its transcriptome to understand the genomewide role of GPA1 and compared it with that of our similar analysis of a GCR1 mutant (Chakraborty et al. 2015, PLoS ONE 10(2):e0117819). We found 394 GPA1-regulated genes spanning 79 biological processes, including biotic and abiotic stresses, development, flavonoid biosynthesis, transcription factors, transporters and nitrate/phosphate responses. Many of them are either unknown or unclaimed explicitly in other published gpa1 mutant transcriptome analyses. A comparison of all known GPA1-regulated genes (including the above 394) with 350 GCR1-regulated genes revealed 114 common genes. This can be best explained by GCR1-GPA1 coupling, or by convergence of their independent signaling pathways. Though the common genes in our GPA1 and GCR1 mutant datasets constitute only 26% of the GPA1-regulated and 30% of the GCR1-responsive genes, they belong to nearly half of all the processes affected in both the mutants. Thus, GCR1 and GPA1 regulate not only some common genes, but also different genes belonging to the same processes to achieve similar outcomes. Overall, we validate some known and report many hitherto unknown roles of GPA1 in plants, including agronomically important ones such as biotic stress and nutrient response, and also provide compelling genetic evidence to revisit the role of GCR1 in G-protein signalling.
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Affiliation(s)
- Navjyoti Chakraborty
- University School of Biotechnology, G.G.S. Indraprastha University, Sector 16 C, Dwarka, New Delhi, 110078, India
| | - Priyanka Sharma
- University School of Biotechnology, G.G.S. Indraprastha University, Sector 16 C, Dwarka, New Delhi, 110078, India
| | - Kostya Kanyuka
- Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Ravi Ramesh Pathak
- University School of Biotechnology, G.G.S. Indraprastha University, Sector 16 C, Dwarka, New Delhi, 110078, India
| | | | - Richard Hooley
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Nandula Raghuram
- University School of Biotechnology, G.G.S. Indraprastha University, Sector 16 C, Dwarka, New Delhi, 110078, India.
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Kaurilind E, Xu E, Brosché M. A genetic framework for H2O2 induced cell death in Arabidopsis thaliana. BMC Genomics 2015; 16:837. [PMID: 26493993 PMCID: PMC4619244 DOI: 10.1186/s12864-015-1964-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 09/29/2015] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND To survive in a changing environment plants constantly monitor their surroundings. In response to several stresses and during photorespiration plants use reactive oxygen species as signaling molecules. The Arabidopsis thaliana catalase2 (cat2) mutant lacks a peroxisomal catalase and under photorespiratory conditions accumulates H2O2, which leads to activation of cell death. METHODS A cat2 double mutant collection was generated through crossing and scored for cell death in different assays. Selected double mutants were further analyzed for photosynthetic performance and H2O2 accumulation. RESULTS We used a targeted mutant analysis with more than 50 cat2 double mutants to investigate the role of stress hormones and other defense regulators in H2O2-mediated cell death. Several transcription factors (AS1, MYB30, MYC2, WRKY70), cell death regulators (RCD1, DND1) and hormone regulators (AXR1, ERA1, SID2, EDS1, SGT1b) were essential for execution of cell death in cat2. Genetic loci required for cell death in cat2 was compared with regulators of cell death in spontaneous lesion mimic mutants and led to the identification of a core set of plant cell death regulators. Analysis of gene expression data from cat2 and plants undergoing cell death revealed similar gene expression profiles, further supporting the existence of a common program for regulation of plant cell death. CONCLUSIONS Our results provide a genetic framework for further study on the role of H2O2 in regulation of cell death. The hormones salicylic acid, jasmonic acid and auxin, as well as their interaction, are crucial determinants of cell death regulation.
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Affiliation(s)
- Eve Kaurilind
- Division of Plant Biology, Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland.
- Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia.
| | - Enjun Xu
- Division of Plant Biology, Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland.
| | - Mikael Brosché
- Division of Plant Biology, Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland.
- Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411, Estonia.
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Yu Y, Assmann SM. The heterotrimeric G-protein β subunit, AGB1, plays multiple roles in the Arabidopsis salinity response. PLANT, CELL & ENVIRONMENT 2015; 38:2143-56. [PMID: 25808946 DOI: 10.1111/pce.12542] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 02/20/2015] [Accepted: 03/05/2015] [Indexed: 05/07/2023]
Abstract
Salinity stress includes both osmotic and ionic toxicity. Sodium homeostasis is influenced by Na(+) uptake and extrusion, vacuolar Na(+) compartmentation and root to shoot Na(+) translocation via transpiration. The knockout mutant of the Arabidopsis heterotrimeric G-protein Gβ subunit, agb1, is hypersensitive to salt, exhibiting a leaf bleaching phenotype. We show that AGB1 is mainly involved in the ionic toxicity component of salinity stress and plays roles in multiple processes of Na(+) homeostasis. agb1 mutants accumulate more Na(+) and less K(+) in both shoots and roots of hydroponically grown plants, as measured by inductively coupled plasma atomic emission spectrometry. agb1 plants have higher root to shoot translocation rates of radiolabelled (24) Na(+) under transpiring conditions, as a result of larger stomatal apertures and increased stomatal conductance. (24) Na(+) tracer experiments also show that (24) Na(+) uptake rates by excised roots of agb1 and wild type are initially equal, but that agb1 has higher net Na(+) uptake at 90 min, implicating possible involvement of AGB1 in the regulation of Na(+) efflux. Calcium alleviates the salt hypersensitivity of agb1 by reducing Na(+) accumulation to below the toxicity threshold. Our results provide new insights into the regulatory pathways underlying plant responses to salinity stress, an important agricultural problem.
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Affiliation(s)
- Yunqing Yu
- Biology Department, Pennsylvania State University, University Park, PA, 16802-5301, USA
| | - Sarah M Assmann
- Biology Department, Pennsylvania State University, University Park, PA, 16802-5301, USA
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Chakravorty D, Gookin TE, Milner MJ, Yu Y, Assmann SM. Extra-Large G Proteins Expand the Repertoire of Subunits in Arabidopsis Heterotrimeric G Protein Signaling. PLANT PHYSIOLOGY 2015; 169:512-29. [PMID: 26157115 PMCID: PMC4577375 DOI: 10.1104/pp.15.00251] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 07/06/2015] [Indexed: 05/21/2023]
Abstract
Heterotrimeric G proteins, consisting of Gα, Gβ, and Gγ subunits, are a conserved signal transduction mechanism in eukaryotes. However, G protein subunit numbers in diploid plant genomes are greatly reduced as compared with animals and do not correlate with the diversity of functions and phenotypes in which heterotrimeric G proteins have been implicated. In addition to GPA1, the sole canonical Arabidopsis (Arabidopsis thaliana) Gα subunit, Arabidopsis has three related proteins: the extra-large GTP-binding proteins XLG1, XLG2, and XLG3. We demonstrate that the XLGs can bind Gβγ dimers (AGB1 plus a Gγ subunit: AGG1, AGG2, or AGG3) with differing specificity in yeast (Saccharomyces cerevisiae) three-hybrid assays. Our in silico structural analysis shows that XLG3 aligns closely to the crystal structure of GPA1, and XLG3 also competes with GPA1 for Gβγ binding in yeast. We observed interaction of the XLGs with all three Gβγ dimers at the plasma membrane in planta by bimolecular fluorescence complementation. Bioinformatic and localization studies identified and confirmed nuclear localization signals in XLG2 and XLG3 and a nuclear export signal in XLG3, which may facilitate intracellular shuttling. We found that tunicamycin, salt, and glucose hypersensitivity and increased stomatal density are agb1-specific phenotypes that are not observed in gpa1 mutants but are recapitulated in xlg mutants. Thus, XLG-Gβγ heterotrimers provide additional signaling modalities for tuning plant G protein responses and increase the repertoire of G protein heterotrimer combinations from three to 12. The potential for signal partitioning and competition between the XLGs and GPA1 is a new paradigm for plant-specific cell signaling.
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Affiliation(s)
- David Chakravorty
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Timothy E Gookin
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Matthew J Milner
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Yunqing Yu
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Sarah M Assmann
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
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Ishida T, Tabata R, Yamada M, Aida M, Mitsumasu K, Fujiwara M, Yamaguchi K, Shigenobu S, Higuchi M, Tsuji H, Shimamoto K, Hasebe M, Fukuda H, Sawa S. Heterotrimeric G proteins control stem cell proliferation through CLAVATA signaling in Arabidopsis. EMBO Rep 2014; 15:1202-9. [PMID: 25260844 DOI: 10.15252/embr.201438660] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Cell-to-cell communication is a fundamental mechanism for coordinating developmental and physiological events in multicellular organisms. Heterotrimeric G proteins are key molecules that transmit extracellular signals; similarly, CLAVATA signaling is a crucial regulator in plant development. Here, we show that Arabidopsis thaliana Gβ mutants exhibit an enlarged stem cell region, which is similar to that of clavata mutants. Our genetic and cell biological analyses suggest that the G protein beta-subunit1 AGB1 and RPK2, one of the major CLV3 peptide hormone receptors, work synergistically in stem cell homeostasis through their physical interactions. We propose that AGB1 and RPK2 compose a signaling module to facilitate meristem development.
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Affiliation(s)
- Takashi Ishida
- Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan
| | - Ryo Tabata
- Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan
| | - Masashi Yamada
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan Department of Biology and Institute for Genome Science and Policy Center for Systems Biology, Duke University, Durham, NC, USA
| | - Mitsuhiro Aida
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
| | - Kanako Mitsumasu
- Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan
| | - Masayuki Fujiwara
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
| | - Katsushi Yamaguchi
- Functional Genomics Facility, National Institute for Basic Biology, Okazaki, Japan
| | - Shuji Shigenobu
- Functional Genomics Facility, National Institute for Basic Biology, Okazaki, Japan
| | - Masayuki Higuchi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
| | - Hiroyuki Tsuji
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
| | - Ko Shimamoto
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
| | - Mitsuyasu Hasebe
- Division of Evolutionary Biology, National Institute for Basic Biology, Okazaki, Japan School of Life Science, The Graduate University for Advanced Studies, Okazaki, Japan
| | - Hiroo Fukuda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Shinichiro Sawa
- Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan
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Colaneri AC, Tunc-Ozdemir M, Huang JP, Jones AM. Growth attenuation under saline stress is mediated by the heterotrimeric G protein complex. BMC PLANT BIOLOGY 2014; 14:129. [PMID: 24884438 PMCID: PMC4061919 DOI: 10.1186/1471-2229-14-129] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/30/2014] [Indexed: 05/18/2023]
Abstract
BACKGROUND Plant growth is plastic, able to rapidly adjust to fluctuation in environmental conditions such as drought and salinity. Due to long-term irrigation use in agricultural systems, soil salinity is increasing; consequently crop yield is adversely affected. It is known that salt tolerance is a quantitative trait supported by genes affecting ion homeostasis, ion transport, ion compartmentalization and ion selectivity. Less is known about pathways connecting NaCl and cell proliferation and cell death. Plant growth and cell proliferation is, in part, controlled by the concerted activity of the heterotrimeric G-protein complex with glucose. Prompted by the abundance of stress-related, functional annotations of genes encoding proteins that interact with core components of the Arabidopsis heterotrimeric G protein complex (AtRGS1, AtGPA1, AGB1, and AGG), we tested the hypothesis that G proteins modulate plant growth under salt stress. RESULTS Na+ activates G signaling as quantitated by internalization of Arabidopsis Regulator of G Signaling protein 1 (AtRGS1). Despite being components of a singular signaling complex loss of the Gβ subunit (agb1-2 mutant) conferred accelerated senescence and aborted development in the presence of Na+, whereas loss of AtRGS1 (rgs1-2 mutant) conferred Na+ tolerance evident as less attenuated shoot growth and senescence. Site-directed changes in the Gα and Gβγ protein-protein interface were made to disrupt the interaction between the Gα and Gβγ subunits in order to elevate free activated Gα subunit and free Gβγ dimer at the plasma membrane. These mutations conferred sodium tolerance. Glucose in the growth media improved the survival under salt stress in Col but not in agb1-2 or rgs1-2 mutants. CONCLUSIONS These results demonstrate a direct role for G-protein signaling in the plant growth response to salt stress. The contrasting phenotypes of agb1-2 and rgs1-2 mutants suggest that G-proteins balance growth and death under salt stress. The phenotypes of the loss-of-function mutations prompted the model that during salt stress, G activation promotes growth and attenuates senescence probably by releasing ER stress.
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Affiliation(s)
- Alejandro C Colaneri
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill NC, 27599, USA
| | - Meral Tunc-Ozdemir
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill NC, 27599, USA
| | - Jian Ping Huang
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill NC, 27599, USA
| | - Alan M Jones
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill NC, 27599, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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Gorecka M, Alvarez-Fernandez R, Slattery K, McAusland L, Davey PA, Karpinski S, Lawson T, Mullineaux PM. Abscisic acid signalling determines susceptibility of bundle sheath cells to photoinhibition in high light-exposed Arabidopsis leaves. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130234. [PMID: 24591719 DOI: 10.1098/rstb.2013.0234] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The rapid induction of the bundle sheath cell (BSC)-specific expression of ASCORBATE PEROXIDASE2 (APX2) in high light (HL)-exposed leaves of Arabidopsis thaliana is, in part, regulated by the hormone abscisic acid (ABA) produced by vascular parenchyma cells. In this study, we provide more details of the ABA signalling that regulates APX2 expression and consider its importance in the photosynthetic responses of BSCs and whole leaves. This was done using a combination of analyses of gene expression and chlorophyll a fluorescence of both leaves and individual BSCs and mesophyll cells. The regulation of APX2 expression occurs by the combination of the protein kinase SnRK2.6 (OST1):protein phosphatase 2C ABI2 and a Gα (GPA1)-regulated signalling pathway. The use of an ost1-1/gpa1-4 mutant established that these signalling pathways are distinct but interact to regulate APX2. In HL-exposed leaves, BSC chloroplasts were more susceptible to photoinhibition than those of mesophyll cells. The activity of the ABA-signalling network determined the degree of susceptibility of BSCs to photoinhibition by influencing non-photochemical quenching. By contrast, in HL-exposed whole leaves, ABA signalling did not have any major influence on their transcriptomes nor on their susceptibility to photoinhibition, except where guard cell responses were observed.
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Affiliation(s)
- Magdalena Gorecka
- Department of Genetics, Breeding and Plant Biotechnology, Warsaw University of Life Sciences, , Nowoursynowska Street 159, Warszawa 02-776, Poland
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Igamberdiev AU, Eprintsev AT, Fedorin DN, Popov VN. Phytochrome-mediated regulation of plant respiration and photorespiration. PLANT, CELL & ENVIRONMENT 2014; 37:290-299. [PMID: 23772790 DOI: 10.1111/pce.12155] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 06/02/2023]
Abstract
The expression of genes encoding various enzymes participating in photosynthetic and respiratory metabolism is regulated by light via the phytochrome system. While many photosynthetic, photorespiratory and some respiratory enzymes, such as the rotenone-insensitive NADH and NADPH dehydrogenases and the alternative oxidase, are stimulated by light, succinate dehydrogenase, subunits of the pyruvate dehydrogenase complex, cytochrome oxidase and fumarase are inhibited via the phytochrome mechanism. The effect of light, therefore, imposes limitations on the tricarboxylic acid cycle and on the mitochondrial electron transport coupled to ATP synthesis, while the non-coupled pathways become activated. Phytochrome-mediated regulation of gene expression also creates characteristic distribution patterns of photosynthetic, photorespiratory and respiratory enzymes across the leaf generating different populations of mitochondria, either enriched by glycine decarboxylase (in the upper part) or by succinate dehydrogenase (in the bottom part of the leaf).
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Affiliation(s)
- Abir U Igamberdiev
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada, A1B 3X9
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42
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Kushwah S, Laxmi A. The interaction between glucose and cytokinin signal transduction pathway in Arabidopsis thaliana. PLANT, CELL & ENVIRONMENT 2014; 37:235-53. [PMID: 23763631 DOI: 10.1111/pce.12149] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 05/20/2013] [Indexed: 05/07/2023]
Abstract
Cytokinins (CKs) and glucose (GLC) control a number of common responses in plants. We hypothesize that there may be an extensive overlap between CK- and GLC-signalling pathways. Microarray along with physiological analysis has been performed to find out the interdependence/overlap between CK and GLC signal transduction pathways in Arabidopsis seedlings. GLC could transcriptionally affect 76% of CK-regulated genes at whole genome level, 89% of which are agonistically regulated. GLC may also affect CK-regulated gene expression via non-transcriptional pathways. GLC can regulate several genes involved in CK metabolism and signalling. A number of gene families involved in development and stress are commonly regulated by CK and GLC. Physiologically, both GLC and CK could regulate hypocotyl length in dark. GLC and CK signalling may integrate at the level of type A Arabidopsis response regulators (ARRs) in controlling hypocotyl length. Both GLC and CK signalling cannot alter hypocotyl length in dark in auxin-signalling mutants auxin response2/indole-3-acetic acid7 (AXR2/IAA7) and AXR3/IAA17 suggesting that they may involve auxin-signalling component as a nodal point. Here, we demonstrate that there is an extensive overlap between CK- and GLC-regulated gene expression and physiological responses.
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Affiliation(s)
- Sunita Kushwah
- National Institute of Plant Genome Research, Aruna Asaf Ali Road, New Delhi, 110067, India
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43
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Abstract
Investigators studying G protein-coupled signaling--often called the best-understood pathway in the world owing to intense research in medical fields--have adopted plants as a new model to explore the plasticity and evolution of G signaling. Much research on plant G signaling has not disappointed. Although plant cells have most of the core elements found in animal G signaling, differences in network architecture and intrinsic properties of plant G protein elements make G signaling in plant cells distinct from the animal paradigm. In contrast to animal G proteins, plant G proteins are self-activating, and therefore regulation of G activation in plants occurs at the deactivation step. The self-activating property also means that plant G proteins do not need and therefore do not have typical animal G protein-coupled receptors. Targets of activated plant G proteins, also known as effectors, are unlike effectors in animal cells. The simpler repertoire of G signal elements in Arabidopsis makes G signaling easier to manipulate in a multicellular context.
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Affiliation(s)
- Daisuke Urano
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Alan M. Jones
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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44
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Jin X, Wang RS, Zhu M, Jeon BW, Albert R, Chen S, Assmann SM. Abscisic acid-responsive guard cell metabolomes of Arabidopsis wild-type and gpa1 G-protein mutants. THE PLANT CELL 2013; 25:4789-811. [PMID: 24368793 PMCID: PMC3903988 DOI: 10.1105/tpc.113.119800] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 10/18/2013] [Accepted: 11/27/2013] [Indexed: 05/03/2023]
Abstract
Individual metabolites have been implicated in abscisic acid (ABA) signaling in guard cells, but a metabolite profile of this specialized cell type is lacking. We used liquid chromatography-multiple reaction monitoring mass spectrometry for targeted analysis of 85 signaling-related metabolites in Arabidopsis thaliana guard cell protoplasts over a time course of ABA treatment. The analysis utilized ∼ 350 million guard cell protoplasts from ∼ 30,000 plants of the Arabidopsis Columbia accession (Col) wild type and the heterotrimeric G-protein α subunit mutant, gpa1, which has ABA-hyposensitive stomata. These metabolomes revealed coordinated regulation of signaling metabolites in unrelated biochemical pathways. Metabolites clustered into different temporal modules in Col versus gpa1, with fewer metabolites showing ABA-altered profiles in gpa1. Ca(2+)-mobilizing agents sphingosine-1-phosphate and cyclic adenosine diphosphate ribose exhibited weaker ABA-stimulated increases in gpa1. Hormone metabolites were responsive to ABA, with generally greater responsiveness in Col than in gpa1. Most hormones also showed different ABA responses in guard cell versus mesophyll cell metabolomes. These findings suggest that ABA functions upstream to regulate other hormones, and are also consistent with G proteins modulating multiple hormonal signaling pathways. In particular, indole-3-acetic acid levels declined after ABA treatment in Col but not gpa1 guard cells. Consistent with this observation, the auxin antagonist α-(phenyl ethyl-2-one)-indole-3-acetic acid enhanced ABA-regulated stomatal movement and restored partial ABA sensitivity to gpa1.
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Affiliation(s)
- Xiaofen Jin
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Rui-Sheng Wang
- Physics Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Mengmeng Zhu
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Byeong Wook Jeon
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Reka Albert
- Physics Department, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Sixue Chen
- Department of Biology, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida, Gainesville, Florida 32610
| | - Sarah M. Assmann
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
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45
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Roy A, Sahoo D, Tripathy BC. Involvement of phytochrome A in suppression of photomorphogenesis in rice seedling grown in red light. PLANT, CELL & ENVIRONMENT 2013; 36:2120-2134. [PMID: 23495675 DOI: 10.1111/pce.12099] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2010] [Revised: 03/05/2013] [Accepted: 03/06/2013] [Indexed: 06/01/2023]
Abstract
Plants have evolved a remarkable capacity to track and respond to fluctuations of light quality and intensity that influence photomorphogenesis facilitated through several photoreceptors, which include a small family of phytochromes. Rice seedlings grown on germination paper in red light for 48 h having their shoot bottom exposed had suppressed photomorphogenesis and were deficient in chlorophyll. Seedlings grown under identical light regime having their shoot bottom covered were green and accumulated chlorophyll. Further, etiolated seedlings with their shoot bottom exposed, when grown in 4 min red/far-red cycles for 48 h, accumulated chlorophyll demonstrating the reversal of suppression of photomorphogenesis by far-red light. It implicates the involvement of phytochrome. Immunoblot analysis showed the persistence of photolabile phytochrome A protein for 48 h in seedlings grown in red light with their shoot bottom exposed, suggesting its involvement in suppression of photomorphogenesis. This was further corroborated in phyA seedlings that turned green when grown in red light having their shoot bottom exposed. Calmodulin (CaM) antagonist N-(6-aminohexyl)-5-chloro-1-napthalene sulphonamide or trifluoperazine substantially restored photomorphogenesis both in the wild type (WT) and phyA demonstrating the involvement of CaM-dependent kinases in the down-regulation of the greening process. Results demonstrate that red light-induced suppression of photomorphogenesis, perceived in the shoot bottom, is a red high irradiance response of PhyA.
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Affiliation(s)
- Ansuman Roy
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, Delhi, India
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Lorek J, Griebel T, Jones AM, Panstruga R. The role of Arabidopsis heterotrimeric G-protein subunits in MLO2 function and MAMP-triggered immunity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:991-1003. [PMID: 23656333 PMCID: PMC4864957 DOI: 10.1094/mpmi-03-13-0077-r] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Heterotrimeric G-proteins, composed of Gα, Gβ, and Gγ subunits, regulate many fundamental processes in plants. In animals, ligand binding to seven transmembrane (7TM) cell surface receptors designated G-protein coupled receptors (GPCR) leads to heterotrimeric G-protein activation. Because the plant G-protein complex is constitutively active, the exact role of plant 7TM proteins in this process is unclear. Members of the mildew resistance locus O (MLO) family represent the best-characterized 7TM plant proteins. Although genetic ablation of either MLO2 or G-proteins alters susceptibility to pathogens in Arabidopsis thaliana, it is unknown whether G-proteins directly couple signaling through MLO2. Here, we exploited two well-documented phenotypes of mlo2 mutants, broad-spectrum powdery mildew resistance and spontaneous callose deposition in leaf mesophyll cells, to assess the relationship of MLO2 proteins to the G-protein complex. Although our data reveal modulation of antifungal defense responses by Gβ and Gγ subunits and a role for the Gγ1 subunit in mlo2-conditioned callose deposition, our findings overall are inconsistent with a role of MLO2 as a canonical GPCR. We discovered that mutants lacking the Gβ subunit show delayed accumulation of a subset of defense-associated genes following exposure to the microbe-associated molecular pattern flg22. Moreover, Gβ mutants were found to be hypersusceptible to spray inoculation with the bacterial pathogen Pseudomonas syringae.
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Affiliation(s)
- Justine Lorek
- Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Köln, Germany
- RWTH Aachen University, Institute for Biology I, Unit of Plant Molecular Cell Biology, Worringer Weg 1, D-52056 Aachen
| | - Thomas Griebel
- Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Köln, Germany
| | - Alan M. Jones
- University of North Carolina at Chapel Hill, Departments of Biology and Pharmacology, North Carolina, USA
| | - Ralph Panstruga
- Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Köln, Germany
- RWTH Aachen University, Institute for Biology I, Unit of Plant Molecular Cell Biology, Worringer Weg 1, D-52056 Aachen
- corresponding author;
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47
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Elsharkawy MM, Shimizu M, Takahashi H, Ozaki K, Hyakumachi M. Induction of Systemic Resistance against Cucumber mosaic virus in Arabidopsis thaliana by Trichoderma asperellum SKT-1. THE PLANT PATHOLOGY JOURNAL 2013; 29:193-200. [PMID: 25288946 DOI: 10.5423/ppj.si.07.2012.0117] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 01/22/2013] [Accepted: 01/22/2013] [Indexed: 05/26/2023]
Abstract
Trichoderma asperellum SKT-1 is a microbial pesticide that is very effective against various diseases. Our study was undertaken to evaluate T. asperellum SKT-1 for induction of resistance against yellow strain of Cucumber mosaic virus (CMV-Y) in Arabidopsis plants. Disease severity was rated at 2 weeks post inoculation (WPI). CMV titre in Arabidopsis leaves was determined by indirect enzyme-linked immunosorbent assay (ELISA) at 2 WPI. Our results demonstrated that among all Arabidopsis plants treated with barley grain inoculum (BGI) of SKT-1 NahG and npr1 plants showed no significant reduction in disease severity and CMV titre as compared with control plants. In contrast, disease severity and CMV titre were significantly reduced in all Arabidopsis plants treated with culture filtrate (CF) of SKT-1 as compared with control plants. RT-PCR results showed increased expression levels of SA-inducible genes, but not JA/ET-inducible genes, in leaves of BGI treated plants. Moreover, expression levels of SA- and JA/ET-inducible genes were increased in leaves of CF treated plants. In conclusion, BGI treatment induced systemic resistance against CMV through SA signaling cascade in Arabidopsis plants. While, treatment with CF of SKT-1 mediated the expression of a majority of the various pathogen related genes, which led to the increased defense mechanism against CMV infection.
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Affiliation(s)
- Mohsen Mohamed Elsharkawy
- United Graduate School of Agriculture Science, Gifu University, Gifu City 501-1193, Japan Department of Agricultural Botany, Faculty of Agriculture, Kafr El-Sheikh University, 33516, Egypt
| | - Masafumi Shimizu
- Laboratory of Plant Pathology, Faculty of Applied Biological Sciences, Gifu University, Gifu City 501-1193, Japan
| | - Hideki Takahashi
- Department of Life Science, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan
| | - Kouichi Ozaki
- Life Science Research Institute, Kumiai Chemical Industry Co., Ltd, Kikugawa, Shizuoka, Japan
| | - Mitsuro Hyakumachi
- Laboratory of Plant Pathology, Faculty of Applied Biological Sciences, Gifu University, Gifu City 501-1193, Japan
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48
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Elsharkawy MM, Shimizu M, Takahashi H, Ozaki K, Hyakumachi M. Induction of Systemic Resistance against Cucumber mosaic virus in Arabidopsis thaliana by Trichoderma asperellum SKT-1. THE PLANT PATHOLOGY JOURNAL 2013; 29:193-200. [PMID: 25288946 PMCID: PMC4174775 DOI: 10.5423/ppj.si.07.2012.01] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 01/22/2013] [Accepted: 01/22/2013] [Indexed: 05/12/2023]
Abstract
Trichoderma asperellum SKT-1 is a microbial pesticide that is very effective against various diseases. Our study was undertaken to evaluate T. asperellum SKT-1 for induction of resistance against yellow strain of Cucumber mosaic virus (CMV-Y) in Arabidopsis plants. Disease severity was rated at 2 weeks post inoculation (WPI). CMV titre in Arabidopsis leaves was determined by indirect enzyme-linked immunosorbent assay (ELISA) at 2 WPI. Our results demonstrated that among all Arabidopsis plants treated with barley grain inoculum (BGI) of SKT-1 NahG and npr1 plants showed no significant reduction in disease severity and CMV titre as compared with control plants. In contrast, disease severity and CMV titre were significantly reduced in all Arabidopsis plants treated with culture filtrate (CF) of SKT-1 as compared with control plants. RT-PCR results showed increased expression levels of SA-inducible genes, but not JA/ET-inducible genes, in leaves of BGI treated plants. Moreover, expression levels of SA- and JA/ET-inducible genes were increased in leaves of CF treated plants. In conclusion, BGI treatment induced systemic resistance against CMV through SA signaling cascade in Arabidopsis plants. While, treatment with CF of SKT-1 mediated the expression of a majority of the various pathogen related genes, which led to the increased defense mechanism against CMV infection.
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Affiliation(s)
- Mohsen Mohamed Elsharkawy
- United Graduate School of Agriculture Science, Gifu University, Gifu City 501-1193, Japan Department of Agricultural Botany, Faculty of Agriculture, Kafr El-Sheikh University, 33516, Egypt
| | - Masafumi Shimizu
- Laboratory of Plant Pathology, Faculty of Applied Biological Sciences, Gifu University, Gifu City 501-1193, Japan
| | - Hideki Takahashi
- Department of Life Science, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan
| | - Kouichi Ozaki
- Life Science Research Institute, Kumiai Chemical Industry Co., Ltd, Kikugawa, Shizuoka, Japan
| | - Mitsuro Hyakumachi
- Laboratory of Plant Pathology, Faculty of Applied Biological Sciences, Gifu University, Gifu City 501-1193, Japan
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Torres MA, Morales J, Sánchez-Rodríguez C, Molina A, Dangl JL. Functional interplay between Arabidopsis NADPH oxidases and heterotrimeric G protein. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:686-94. [PMID: 23441575 DOI: 10.1094/mpmi-10-12-0236-r] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The plant NADPH oxidases produce reactive oxygen species (ROS) in response to pathogens that have diverse functions in different cellular contexts. Distinct phenotypic outcomes may derive from the interaction of NADPH oxidase-dependent ROS with other signaling components that mediate defense activation. We analyze the interaction between NADPH oxidases AtRbohD and AtRbohF and the Arabidopsis heterotrimeric G protein. The Gβ subunit (AGB1) of the heterotrimeric G protein is required for full disease resistance to different Pseudomonas syringae strains. Genetic studies reveal that, upon P. syringae infection, AGB1 and AtRbohD and AtRbohF can function in the same pathway, as the agb1 null allele is epistatic to the NADPH oxidase null alleles, combinatorial mutants display the agb1 phenotypes, and agb1 suppresses some of the atrbohD atrbohF double mutant phenotypes. In contrast, increased susceptibility to the necrotrophic fungus Plectosphaerella cucumerina displayed by agb1 and atrbohD atrbohF is enhanced in the agb1 atrbohD atrbohF triple mutant, suggesting that NADPH oxidase and heterotrimeric G proteins mediate different response pathways in response to this necrotrophic pathogen. The defense response mediated by AGB1 is independent of pathogen-dependent salicylic acid accumulation and signaling, as the agb1 sid2 (isochorismate synthase 2) double mutant showed enhanced disease susceptibility to P. syringae and Plectosphaerella cucumerina as compared with both single mutants. This study exemplifies the complex interplay between signaling events mediating defense activation, depending on the type of plant-pathogen interaction.
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50
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Urano D, Chen JG, Botella JR, Jones AM. Heterotrimeric G protein signalling in the plant kingdom. Open Biol 2013. [PMID: 23536550 DOI: 10.1098/rsob.12.0186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
Abstract
In animals, heterotrimeric G proteins, comprising α-, β-and γ-subunits, perceive extracellular stimuli through cell surface receptors, and transmit signals to ion channels, enzymes and other effector proteins to affect numerous cellular behaviours. In plants, G proteins have structural similarities to the corresponding molecules in animals but transmit signals by atypical mechanisms and effector proteins to control growth, cell proliferation, defence, stomate movements, channel regulation, sugar sensing and some hormonal responses. In this review, we summarize the current knowledge on the molecular regulation of plant G proteins, their effectors and the physiological functions studied mainly in two model organisms: Arabidopsis thaliana and rice (Oryza sativa). We also look at recent progress on structural analyses, systems biology and evolutionary studies.
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Affiliation(s)
- Daisuke Urano
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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