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Sharma S, Ganotra J, Samantaray J, Sahoo RK, Bhardwaj D, Tuteja N. An emerging role of heterotrimeric G-proteins in nodulation and nitrogen sensing. PLANTA 2023; 258:101. [PMID: 37847414 DOI: 10.1007/s00425-023-04251-8] [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: 02/28/2023] [Accepted: 09/25/2023] [Indexed: 10/18/2023]
Abstract
MAIN CONCLUSION A comprehensive understanding of nitrogen signaling cascades involving heterotrimeric G-proteins and their putative receptors can assist in the production of nitrogen-efficient plants. Plants are immobile in nature, so they must endure abiotic stresses including nutrient stress. Plant development and agricultural productivity are frequently constrained by the restricted availability of nitrogen in the soil. Non-legume plants acquire nitrogen from the soil through root membrane-bound transporters. In depleted soil nitrogen conditions, legumes are naturally conditioned to fix atmospheric nitrogen with the aid of nodulation elicited by nitrogen-fixing bacteria. Moreover, apart from the symbiotic nitrogen fixation process, nitrogen uptake from the soil can also be a significant secondary source to satisfy the nitrogen requirements of legumes. Heterotrimeric G-proteins function as molecular switches to help plant cells relay diverse stimuli emanating from external stress conditions. They are comprised of Gα, Gβ and Gγ subunits, which cooperate with several downstream effectors to regulate multiple plant signaling events. In the present review, we concentrate on signaling mechanisms that regulate plant nitrogen nutrition. Our review highlights the potential of heterotrimeric G-proteins, together with their putative receptors, to assist the legume root nodule symbiosis (RNS) cascade, particularly during calcium spiking and nodulation. Additionally, the functions of heterotrimeric G-proteins in nitrogen acquisition by plant roots as well as in improving nitrogen use efficiency (NUE) have also been discussed. Future research oriented towards heterotrimeric G-proteins through genome editing tools can be a game changer in the enhancement of the nitrogen fixation process. This will foster the precise manipulation and production of plants to ensure global food security in an era of climate change by enhancing crop productivity and minimizing reliance on external inputs.
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Affiliation(s)
- Suvriti Sharma
- Department of Botany, Central University of Jammu, Jammu, Jammu and Kashmir, 181143, India
| | - Jahanvi Ganotra
- Department of Botany, Central University of Jammu, Jammu, Jammu and Kashmir, 181143, India
| | - Jyotipriya Samantaray
- Department of Botany, Central University of Jammu, Jammu, Jammu and Kashmir, 181143, India
| | - Ranjan Kumar Sahoo
- Department of Biotechnology, Centurion University of Technology and Management, Bhubaneswar, Odisha, 752050, India
| | - Deepak Bhardwaj
- Department of Botany, Central University of Jammu, Jammu, Jammu and Kashmir, 181143, India.
| | - Narendra Tuteja
- Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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G-Protein Phosphorylation: Aspects of Binding Specificity and Function in the Plant Kingdom. Int J Mol Sci 2022; 23:ijms23126544. [PMID: 35742988 PMCID: PMC9224535 DOI: 10.3390/ijms23126544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 11/22/2022] Open
Abstract
Plant survival depends on adaptive mechanisms that constantly rely on signal recognition and transduction. The predominant class of signal discriminators is receptor kinases, with a vast member composition in plants. The transduction of signals occurs in part by a simple repertoire of heterotrimeric G proteins, with a core composed of α-, β-, and γ-subunits, together with a 7-transmembrane Regulator G Signaling (RGS) protein. With a small repertoire of G proteins in plants, phosphorylation by receptor kinases is critical in regulating the active state of the G-protein complex. This review describes the in vivo detected phosphosites in plant G proteins and conservation scores, and their in vitro corresponding kinases. Furthermore, recently described outcomes, including novel arrestin-like internalization of RGS and a non-canonical phosphorylation switching mechanism that drives G-protein plasticity, are discussed.
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Ghusinga KR, Elston TC, Jones AM. Towards resolution of a paradox in plant G-protein signaling. PLANT PHYSIOLOGY 2022; 188:807-815. [PMID: 34791482 PMCID: PMC8825252 DOI: 10.1093/plphys/kiab534] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/17/2021] [Indexed: 05/20/2023]
Abstract
G-proteins are molecular on-off switches that are involved in transmitting a variety of extracellular signals to their intracellular targets. In animal and yeast systems, the switch property is encoded through nucleotides: a GDP-bound state is the "off-state" and the GTP-bound state is the "on-state". The G-protein cycle consists of the switch turning on through nucleotide exchange facilitated by a G-protein coupled receptor and the switch turning off through hydrolysis of GTP back to GDP, facilitated by a protein designated REGULATOR OF G SIGNALING 1 (RGS). In plants, G-protein signaling dramatically differs from that in animals and yeast. Despite stringent conservation of the nucleotide binding and catalytic structures over the 1.6 billion years that separate the evolution of plants and animals, genetic and biochemical data indicate that nucleotide exchange is less critical for this switch to operate in plants. Also, the loss of the single RGS protein in Arabidopsis (Arabidopsis thaliana) confers unexpectedly weaker phenotypes consistent with a diminished role for the G cycle, at least under static conditions. However, under dynamic conditions, genetic ablation of RGS in Arabidopsis results in a strong phenotype. We explore explanations to this conundrum by formulating a mathematical model that takes into account the accruing evidence for the indispensable role of phosphorylation in G-protein signaling in plants and that the G-protein cycle is needed to process dynamic signal inputs. We speculate that the plant G-protein cycle and its attendant components evolved to process dynamic signals through signaling modulation rather than through on-off, switch-like regulation of signaling. This so-called change detection may impart greater fitness for plants due to their sessility in a dynamic light, temperature, and pest environment.
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Affiliation(s)
- Khem Raj Ghusinga
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, North Carolina, USA
- Computational Medicine Program, University of North Carolina at Chapel Hill, North Carolina, USA
| | - Timothy C Elston
- Department of Pharmacology, University of North Carolina at Chapel Hill, North Carolina, USA
- Computational Medicine Program, University of North Carolina at Chapel Hill, North Carolina, USA
| | - Alan M Jones
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, North Carolina, USA
- Author for communication:
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Ramasamy M, Damaj MB, Vargas-Bautista C, Mora V, Liu J, Padilla CS, Irigoyen S, Saini T, Sahoo N, DaSilva JA, Mandadi KK. A Sugarcane G-Protein-Coupled Receptor, ShGPCR1, Confers Tolerance to Multiple Abiotic Stresses. FRONTIERS IN PLANT SCIENCE 2021; 12:745891. [PMID: 35295863 PMCID: PMC8919185 DOI: 10.3389/fpls.2021.745891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 10/14/2021] [Indexed: 06/14/2023]
Abstract
Sugarcane (Saccharum spp.) is a prominent source of sugar and serves as bioenergy/biomass feedstock globally. Multiple biotic and abiotic stresses, including drought, salinity, and cold, adversely affect sugarcane yield. G-protein-coupled receptors (GPCRs) are components of G-protein-mediated signaling affecting plant growth, development, and stress responses. Here, we identified a GPCR-like protein (ShGPCR1) from sugarcane and energy cane (Saccharum spp. hybrids) and characterized its function in conferring tolerance to multiple abiotic stresses. ShGPCR1 protein sequence contained nine predicted transmembrane (TM) domains connected by four extracellular and four intracellular loops, which could interact with various ligands and heterotrimeric G proteins in the cells. ShGPCR1 sequence displayed other signature features of a GPCR, such as a putative guanidine triphosphate (GTP)-binding domain, as well as multiple myristoylation and protein phosphorylation sites, presumably important for its biochemical function. Expression of ShGPCR1 was upregulated by drought, salinity, and cold stresses. Subcellular imaging and calcium (Ca2+) measurements revealed that ShGPCR1 predominantly localized to the plasma membrane and enhanced intracellular Ca2+ levels in response to GTP, respectively. Furthermore, constitutive overexpression of ShGPCR1 in sugarcane conferred tolerance to the three stressors. The stress-tolerance phenotype of the transgenic lines corresponded with activation of multiple drought-, salinity-, and cold-stress marker genes, such as Saccharum spp. LATE EMBRYOGENESIS ABUNDANT, DEHYDRIN, DROUGHT RESPONSIVE 4, GALACTINOL SYNTHASE, ETHYLENE RESPONSIVE FACTOR 3, SALT OVERLY SENSITIVE 1, VACUOLAR Na+/H+ ANTIPORTER 1, NAM/ATAF1/2/CUC2, COLD RESPONSIVE FACTOR 2, and ALCOHOL DEHYDROGENASE 3. We suggest that ShGPCR1 plays a key role in conferring tolerance to multiple abiotic stresses, and the engineered lines may be useful to enhance sugarcane production in marginal environments with fewer resources.
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Affiliation(s)
- Manikandan Ramasamy
- Texas A&M AgriLife Research and Extension Center, Weslaco, TX, United States
| | - Mona B. Damaj
- Texas A&M AgriLife Research and Extension Center, Weslaco, TX, United States
| | | | - Victoria Mora
- Texas A&M AgriLife Research and Extension Center, Weslaco, TX, United States
| | - Jiaxing Liu
- Texas A&M AgriLife Research and Extension Center, Weslaco, TX, United States
| | - Carmen S. Padilla
- Texas A&M AgriLife Research and Extension Center, Weslaco, TX, United States
| | - Sonia Irigoyen
- Texas A&M AgriLife Research and Extension Center, Weslaco, TX, United States
| | - Tripti Saini
- Department of Biology, University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - Nirakar Sahoo
- Department of Biology, University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - Jorge A. DaSilva
- Texas A&M AgriLife Research and Extension Center, Weslaco, TX, United States
- Department of Soil and Crop Sciences, Texas A&M University, College Station, TX, United States
| | - Kranthi K. Mandadi
- Texas A&M AgriLife Research and Extension Center, Weslaco, TX, United States
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, United States
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P2K1 Receptor, Heterotrimeric Gα Protein and CNGC2/4 Are Involved in Extracellular ATP-Promoted Ion Influx in the Pollen of Arabidopsis thaliana. PLANTS 2021; 10:plants10081743. [PMID: 34451790 PMCID: PMC8400636 DOI: 10.3390/plants10081743] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/20/2021] [Accepted: 08/20/2021] [Indexed: 11/17/2022]
Abstract
As an apoplastic signal, extracellular ATP (eATP) is involved in plant growth and development. eATP promotes tobacco pollen germination (PG) and pollen tube growth (PTG) by stimulating Ca2+ or K+ absorption. Nevertheless, the mechanisms underlying eATP-stimulated ion uptake and their role in PG and PTG are still unclear. Here, ATP addition was found to modulate PG and PTG in 34 plant species and showed a promoting effect in most of these species. Furthermore, by using Arabidopsis thaliana as a model, the role of several signaling components involved in eATP-promoted ion (Ca2+, K+) uptake, PG, and PTG were investigated. ATP stimulated while apyrase inhibited PG and PTG. Patch-clamping results showed that ATP promoted K+ and Ca2+ influx into pollen protoplasts. In loss-of-function mutants of P2K1 (dorn1-1 and dorn1-3), heterotrimeric G protein α subunit (gpa1-1, gpa1-2), or cyclic nucleotide gated ion channel (cngc2, cngc4), eATP-stimulated PG, PTG, and ion influx were all impaired. Our results suggest that these signaling components may be involved in eATP-promoted PG and PTG by regulating Ca2+ or K+ influx in Arabidopsis pollen grains.
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Maruta N, Trusov Y, Urano D, Chakravorty D, Assmann SM, Jones AM, Botella JR. GTP binding by Arabidopsis extra-large G protein 2 is not essential for its functions. PLANT PHYSIOLOGY 2021; 186:1240-1253. [PMID: 33729516 PMCID: PMC8195506 DOI: 10.1093/plphys/kiab119] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 02/19/2021] [Indexed: 05/06/2023]
Abstract
The extra-large guanosine-5'-triphosphate (GTP)-binding protein 2, XLG2, is an unconventional Gα subunit of the Arabidopsis (Arabidopsis thaliana) heterotrimeric GTP-binding protein complex with a major role in plant defense. In vitro biochemical analyses and molecular dynamic simulations show that affinity of XLG2 for GTP is two orders of magnitude lower than that of the conventional Gα, AtGPA1. Here we tested the physiological relevance of GTP binding by XLG2. We generated an XLG2(T476N) variant with abolished GTP binding, as confirmed by in vitro GTPγS binding assay. Yeast three-hybrid, bimolecular fluorescence complementation, and split firefly-luciferase complementation assays revealed that the nucleotide-depleted XLG2(T476N) retained wild-type XLG2-like interactions with the Gβγ dimer and defense-related receptor-like kinases. Both wild-type and nucleotide-depleted XLG2(T476N) restored the defense responses against Fusarium oxysporum and Pseudomonas syringae compromised in the xlg2 xlg3 double mutant. Additionally, XLG2(T476N) was fully functional restoring stomatal density, root growth, and sensitivity to NaCl, but failed to complement impaired germination and vernalization-induced flowering. We conclude that XLG2 is able to function in a GTP-independent manner and discuss its possible mechanisms of action.
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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
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, 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
| | - Daisuke Urano
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore
| | - David Chakravorty
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Sarah M Assmann
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Alan M Jones
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Jose R Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
- Author for communication:
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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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