1
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Cho Y. Arabidopsis AGB1 participates in salinity response through bZIP17-mediated unfolded protein response. BMC PLANT BIOLOGY 2024; 24:586. [PMID: 38902609 PMCID: PMC11191249 DOI: 10.1186/s12870-024-05296-x] [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: 04/15/2024] [Accepted: 06/13/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND Plant heterotrimeric G proteins respond to various environmental stresses, including high salinity. It is known that Gβ subunit AGB1 functions in maintaining local and systemic Na+/K+ homeostasis to accommodate ionic toxicity under salt stress. However, whether AGB1 contributes to regulating gene expression for seedling's survival under high salinity remains unclear. RESULTS We showed that AGB1-Venus localized to nuclei when facing excessive salt, and the induction of a set of bZIP17-dependent salt stress-responsive genes was reduced in the agb1 mutant. We confirmed both genetic and physical interactions of AGB1 and bZIP17 in plant salinity response by comparing salt responses in the single and double mutants of agb1 and bzip17 and by BiFC assay, respectively. In addition, we show that AGB1 depletion decreases nuclei-localization of transgenic mRFP-bZIP17 under salt stress, as shown in s1p s2p double mutant in the Agrobacteria-mediated transient mRFP-bZIP17 expression in young seedlings. CONCLUSIONS Our results indicate that AGB1 functions in S1P and/or S2P-mediated proteolytic processing of bZIP17 under salt stress to regulate the induction of salinity-responsive gene expression.
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Affiliation(s)
- Yueh Cho
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 115201, Taiwan.
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2
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Macelline SP, Godwin ID, Liu G, Restall J, Cantor DI, McInerney BV, Toghyani M, Chrystal PV, Selle PH, Liu SY. Transgenic, high-protein sorghums display promise in poultry diets in an initial comparison. Poult Sci 2024; 103:103698. [PMID: 38657523 PMCID: PMC11063504 DOI: 10.1016/j.psj.2024.103698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/17/2024] [Accepted: 03/26/2024] [Indexed: 04/26/2024] Open
Abstract
This study aimed to compare the inclusion of transgenic sorghums against commercially available sorghums on growth performance in broiler chickens. Isonitrogenous and isoenergetic diets were offered to a total 288 male Ross 308 broiler chickens from 14 to 35 d posthatch. Three dietary treatments were diets based on transgenic sorghums with a mean protein content of 154.7 g/kg and 5 treatments were based on commercially available sorghum hybrids with a mean protein content of 90.6 g/kg. Soybean meal inclusions in the commercial sorghum diets averaged 215 g/kg, which was reduced to 171 g/kg in the transgenic sorghum diets because of the higher protein contents. Overall growth performance was highly satisfactory, and commercial sorghums supported 2.55% (2,330 vs. 2,272 g/bird; P = 0.010) more weight gains and 2.74% (2,929 vs. 2,851 g/bird; P = 0.012) higher feed intakes; however, the transgenic sorghums supported a fractionally better FCR (1.255 vs 1.257; P = 0.826). There were no statistical differences in apparent jejunal and ileal starch and protein (N) digestibility coefficients between treatments. The transgenic sorghum diets generated slightly, but significantly, higher AME:GE ratios and AMEn, but the commercial sorghum diets generated 6.33% (235 vs. 221 g/kg; P < 0.001) greater breast meat yields. Apparent ileal digestibility coefficients of 16 amino acids averaged 0.839 and 0.832 for transgenic and commercial sorghum-based diets, respectively, without any significant differences in individual amino acids. This outcome suggests amino acid digestibilities of the transgenic sorghums may be inherently higher than commercial hybrid sorghums as the 25.7% higher average soybean meal inclusions would have advantaged amino acid digestibilities in commercial sorghum diets. The possibility that the digestibilities of amino acids in the kafirin component of transgenic sorghums was enhanced by modifications to the structure of kafirin protein bodies is discussed. In conclusion, transgenic sorghums with higher protein concentrations led to 20.5% reduction of soybean meal inclusions in broiler diets, and this change did not compromise feed conversion efficiency compared to standard commercial hybrid sorghums.
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Affiliation(s)
- Shemil P Macelline
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, New South Wales 2006; Poultry Research Foundation, The University of Sydney, Camden, New South Wales 2570, Australia
| | - Ian D Godwin
- Centre for Crop Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Guoquan Liu
- Centre for Crop Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jemma Restall
- Centre for Crop Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - David I Cantor
- Australian Proteome Analysis Facility, Macquarie University, Sydney, New South Wales, Australia
| | - Bernard V McInerney
- Australian Proteome Analysis Facility, Macquarie University, Sydney, New South Wales, Australia
| | - Mehdi Toghyani
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, New South Wales 2006; Poultry Research Foundation, The University of Sydney, Camden, New South Wales 2570, Australia
| | | | - Peter H Selle
- Poultry Research Foundation, The University of Sydney, Camden, New South Wales 2570, Australia; Sydney School of Veterinary Science, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Sonia Yun Liu
- School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Sydney, New South Wales 2006.
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3
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Yang S, Jung S, Lee H. Heterotrimeric G Protein-Mediated Signaling Is Involved in Stress-Mediated Growth Inhibition in Arabidopsis thaliana. Int J Mol Sci 2023; 24:11027. [PMID: 37446209 DOI: 10.3390/ijms241311027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 06/30/2023] [Accepted: 07/01/2023] [Indexed: 07/15/2023] Open
Abstract
Heterotrimeric G protein-mediated signaling plays a vital role in physiological and developmental processes in eukaryotes. On the other hand, because of the absence of a G protein-coupled receptor and self-activating mechanism of the Gα subunit, plants appear to have different regulatory mechanisms, which remain to be elucidated, compared to canonical G protein signaling established in animals. Here we report that Arabidopsis heterotrimeric G protein subunits, such as Gα (GPA1) and Gβ (AGB1), regulate plant growth under stress conditions through the analysis of heterotrimeric G protein mutants. Flg22-mediated growth inhibition in wild-type roots was found to be caused by a defect in the elongation zone, which was partially blocked in agb1-2 but not gpa1-4. These results suggest that AGB1 may negatively regulate plant growth under biotic stress conditions. In addition, GPA1 and AGB1 exhibited genetically opposite effects on FCA-mediated growth inhibition under heat stress conditions. Therefore, these results suggest that plant G protein signaling is probably related to stress-mediated growth regulation for developmental plasticity in response to biotic and abiotic stress conditions.
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Affiliation(s)
- Soeun Yang
- Department of Biotechnology, Duksung Women's University, Seoul 03169, Republic of Korea
| | - Seohee Jung
- Department of Biotechnology, Duksung Women's University, Seoul 03169, Republic of Korea
| | - Horim Lee
- Department of Biotechnology, Duksung Women's University, Seoul 03169, Republic of Korea
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4
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Nguyen VC, Nakamura Y. Distinctly localized lipid phosphate phosphatases mediate endoplasmic reticulum glycerolipid metabolism in Arabidopsis. THE PLANT CELL 2023; 35:1548-1571. [PMID: 36718530 PMCID: PMC10118277 DOI: 10.1093/plcell/koad021] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
Inter-organelle communication is an integral subcellular process in cellular homeostasis. In plants, cellular membrane lipids are synthesized in the plastids and endoplasmic reticulum (ER). However, the crosstalk between these organelles in lipid biosynthesis remains largely unknown. Here, we show that a pair of lipid phosphate phosphatases (LPPs) with differential subcellular localizations is required for ER glycerolipid metabolism in Arabidopsis (Arabidopsis thaliana). LPPα2 and LPPε1, which function as phosphatidic acid phosphatases and thus catalyze the core reaction in glycerolipid metabolism, were differentially localized at ER and chloroplast outer envelopes despite their similar tissue expression pattern. No mutant phenotype was observed in single knockout mutants; however, genetic suppression of these LPPs affected pollen growth and ER phospholipid biosynthesis in mature siliques and seeds with compromised triacylglycerol biosynthesis. Although chloroplast-localized, LPPε1 was localized close to the ER and ER-localized LPPα2. This proximal localization is functionally relevant, because overexpression of chloroplastic LPPε1 enhanced ER phospholipid and triacylglycerol biosynthesis similar to the effect of LPPα2 overexpression in mature siliques and seeds. Thus, ER glycerolipid metabolism requires a chloroplast-localized enzyme in Arabidopsis, representing the importance of inter-organelle communication in membrane lipid homeostasis.
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Affiliation(s)
- Van C Nguyen
- RIKEN Center for Sustainable Resource Science (CSRS), Yokohama 230-0045, Japan
- Institute of Plant and Microbial Biology, Academia Sinica, 128 Sec. 2 Academia Rd., Nankang, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung Hsing University, Taipei 11529, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Yuki Nakamura
- RIKEN Center for Sustainable Resource Science (CSRS), Yokohama 230-0045, Japan
- Institute of Plant and Microbial Biology, Academia Sinica, 128 Sec. 2 Academia Rd., Nankang, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung Hsing University, Taipei 11529, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan
- Graduate School of Science, The University of Tokyo, Tokyo 113-8654, Japan
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5
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Xiong XX, Liu Y, Zhang LL, Li XJ, Zhao Y, Zheng Y, Yang QH, Yang Y, Min DH, Zhang XH. G-Protein β-Subunit Gene TaGB1-B Enhances Drought and Salt Resistance in Wheat. Int J Mol Sci 2023; 24:ijms24087337. [PMID: 37108500 PMCID: PMC10138664 DOI: 10.3390/ijms24087337] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 03/28/2023] [Accepted: 04/05/2023] [Indexed: 04/29/2023] Open
Abstract
In the hexaploid wheat genome, there are three Gα genes, three Gβ and twelve Gγ genes, but the function of Gβ in wheat has not been explored. In this study, we obtained the overexpression of TaGB1 Arabidopsis plants through inflorescence infection, and the overexpression of wheat lines was obtained by gene bombardment. The results showed that under drought and NaCl treatment, the survival rate of Arabidopsis seedlings' overexpression of TaGB1-B was higher than that of the wild type, while the survival rate of the related mutant agb1-2 was lower than that of the wild type. The survival rate of wheat seedlings with TaGB1-B overexpression was higher than that of the control. In addition, under drought and salt stress, the levels of superoxide dismutase (SOD) and proline (Pro) in the wheat overexpression of TaGB1-B were higher than that of the control, and the concentration of malondialdehyde (MDA) was lower than that of the control. This indicates that TaGB1-B could improve the drought resistance and salt tolerance of Arabidopsis and wheat by scavenging active oxygen. Overall, this work provides a theoretical basis for wheat G-protein β-subunits in a further study, and new genetic resources for the cultivation of drought-tolerant and salt-tolerant wheat varieties.
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Affiliation(s)
- Xin-Xin Xiong
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
| | - Yang Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
| | - Li-Li Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
| | - Xiao-Jian Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
| | - Yue Zhao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
| | - Yan Zheng
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
| | - Qian-Hui Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
| | - Yan Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
| | - Dong-Hong Min
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
| | - Xiao-Hong Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling 712100, China
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6
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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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7
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Kankanamge D, Tennakoon M, Karunarathne A, Gautam N. G protein gamma subunit, a hidden master regulator of GPCR signaling. J Biol Chem 2022; 298:102618. [PMID: 36272647 PMCID: PMC9678972 DOI: 10.1016/j.jbc.2022.102618] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/21/2022] Open
Abstract
Heterotrimeric G proteins (αβγ subunits) that are activated by G protein-coupled receptors (GPCRs) mediate the biological responses of eukaryotic cells to extracellular signals. The α subunits and the tightly bound βγ subunit complex of G proteins have been extensively studied and shown to control the activity of effector molecules. In contrast, the potential roles of the large family of γ subunits have been less studied. In this review, we focus on present knowledge about these proteins. Induced loss of individual γ subunit types in animal and plant models result in strikingly distinct phenotypes indicating that γ subtypes play important and specific roles. Consistent with these findings, downregulation or upregulation of particular γ subunit types result in various types of cancers. Clues about the mechanistic basis of γ subunit function have emerged from imaging the dynamic behavior of G protein subunits in living cells. This shows that in the basal state, G proteins are not constrained to the plasma membrane but shuttle between membranes and on receptor activation βγ complexes translocate reversibly to internal membranes. The translocation kinetics of βγ complexes varies widely and is determined by the membrane affinity of the associated γ subtype. On translocating, some βγ complexes act on effectors in internal membranes. The variation in translocation kinetics determines differential sensitivity and adaptation of cells to external signals. Membrane affinity of γ subunits is thus a parsimonious and elegant mechanism that controls information flow to internal cell membranes while modulating signaling responses.
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Affiliation(s)
- Dinesh Kankanamge
- Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Mithila Tennakoon
- Department of Chemistry, St Louis University, St Louis, Missouri, USA
| | | | - N Gautam
- Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri, USA; Department of Genetics, Washington University School of Medicine, St Louis, Missouri, USA.
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8
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Li X, Fu Q, Zhao FX, Wu YQ, Zhang TY, Li ZQ, He JM. GCR1 Positively Regulates UV-B- and Ethylene-Induced Stomatal Closure via Activating GPA1-Dependent ROS and NO Production. Int J Mol Sci 2022; 23:ijms23105512. [PMID: 35628324 PMCID: PMC9141438 DOI: 10.3390/ijms23105512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/07/2022] [Accepted: 05/12/2022] [Indexed: 11/30/2022] Open
Abstract
Heterotrimeric G proteins function as key players in guard cell signaling to many stimuli, including ultraviolet B (UV-B) and ethylene, but whether guard cell G protein signaling is activated by the only one potential G protein-coupled receptor, GCR1, is still unclear. Here, we found that gcr1 null mutants showed defects in UV-B- and ethylene-induced stomatal closure and production of reactive oxygen species (ROS) and nitric oxide (NO) in guard cells, but these defects could be rescued by the application of a Gα activator or overexpression of a constitutively active form of Gα subunit GPA1 (cGPA1). Moreover, the exogenous application of hydrogen peroxide (H2O2) or NO triggered stomatal closure in gcr1 mutants and cGPA1 transgenic plants in the absence or presence of UV-B or ethylene, but exogenous ethylene could not rescue the defect of gcr1 mutants in UV-B-induced stomatal closure, and gcr1 mutants did not affect UV-B-induced ethylene production in Arabidopsis leaves. These results indicate that GCR1 positively controls UV-B- and ethylene-induced stomatal closure by activating GPA1-dependent ROS and NO production in guard cells and that ethylene acts upstream of GCR1 to transduce UV-B guard cell signaling, which establishes the existence of a classic paradigm of G protein signaling in guard cell signaling to UV-B and ethylene.
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9
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Avsar B. Effective Strategies for Heterologous Expression of Plant Heterotrimeric
G-protein γ Subunits without Gβ Subunit Partners. Protein Pept Lett 2022; 29:429-439. [DOI: 10.2174/0929866529666220203094448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/27/2021] [Accepted: 12/13/2021] [Indexed: 11/22/2022]
Abstract
Background:
In plants, heterotrimeric G-protein (Gγ) subunits are diverse, and they have
structural plasticity to provide functional selectivity to the heterotrimer. Although the Gβ and Gγ
subunits dimerize to function in the signaling pathway, the interaction mechanism of various Gγ
subunits with the Gβ subunit partners is still elusive.
Objective:
To better understand the interaction mechanism, one approach is to separate the subunits
for the re-assembly in vitro. Hence, developing a reliable method for achieving the efficient
production and purification of these proteins has become necessary.
Method:
In this study, Gγ1 and Gγ2 proteins from Oryza sativa and Arabidopsis thaliana were
successfully identified, cloned, expressed in bacteria, and purified as recombinant proteins with the
fusion tags. Highly expressed recombinant Gγ subunits in E. coli were digested by proteases, which
were also produced in the presented study.
Results:
Preliminary structural characterization studies without the Gβ partners showed that Gγ1
proteins have disordered structures with coiled-coil, α-helix extensions, and loops, whereas the Gγ2
protein has a more dominant β-sheet and turns structure. Finally, computational analyses performed
on Gγ genes have laid the foundation of new targets for biotechnological purposes.
Conclusion:
The proposed optimized expression and purification protocol can contribute to
investigations on the Gβγ binding mechanism in plant G-protein signaling. The investigations on
selective binding are critical to shed light on the role(s) of different plant Gγ subunit types in
biological processes.
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Affiliation(s)
- Bihter Avsar
- Department of Molecular Biology, Genetics and Bioengineering, Faculty of Engineering and Natural Sciences, Sabanci
University, Istanbul, Turkey
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10
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Wang Y, Botella JR. Heterotrimeric G Protein Signaling in Abiotic Stress. PLANTS 2022; 11:plants11070876. [PMID: 35406855 PMCID: PMC9002505 DOI: 10.3390/plants11070876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 11/16/2022]
Abstract
As sessile organisms, plants exhibit extraordinary plasticity and have evolved sophisticated mechanisms to adapt and mitigate the adverse effects of environmental fluctuations. Heterotrimeric G proteins (G proteins), composed of α, β, and γ subunits, are universal signaling molecules mediating the response to a myriad of internal and external signals. Numerous studies have identified G proteins as essential components of the organismal response to stress, leading to adaptation and ultimately survival in plants and animal systems. In plants, G proteins control multiple signaling pathways regulating the response to drought, salt, cold, and heat stresses. G proteins signal through two functional modules, the Gα subunit and the Gβγ dimer, each of which can start either independent or interdependent signaling pathways. Improving the understanding of the role of G proteins in stress reactions can lead to the development of more resilient crops through traditional breeding or biotechnological methods, ensuring global food security. In this review, we summarize and discuss the current knowledge on the roles of the different G protein subunits in response to abiotic stress and suggest future directions for research.
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11
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Ninh TT, Gao W, Trusov Y, Zhao J, Long L, Song C, Botella JR. Tomato and cotton G protein beta subunit mutants display constitutive autoimmune responses. PLANT DIRECT 2021; 5:e359. [PMID: 34765865 PMCID: PMC8573408 DOI: 10.1002/pld3.359] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Heterotrimeric G protein Gβ-deficient mutants in rice and maize display constitutive immune responses, whereas Arabidopsis Gβ mutants show impaired defense, suggesting the existence of functional differences between monocots and dicots. Using CRISPR/Cas9, we produced one hemizygous tomato line with a mutated SlGB1 Gβ gene. Homozygous slgb1 knockout mutants exhibit all the hallmarks of autoimmune mutants, including development of necrotic lesions, constitutive expression of defense-related genes, and high endogenous levels of salicylic acid (SA) and reactive oxygen species, resulting in early seedling lethality. Virus-induced silencing of Gβ in cotton reproduced the symptoms observed in tomato mutants, confirming that the autoimmune phenotype is not limited to monocot species but is also shared by dicots. Even though multiple genes involved in SA and ethylene signaling are highly induced by Gβ silencing in tomato and cotton, co-silencing of SA or ethylene signaling components in cotton failed to suppress the lethal phenotype, whereas co-silencing of the oxidative burst oxidase RbohD can repress lethality. Despite the autoimmune response observed in slgb1 mutants, we show that SlGB1 is a positive regulator of the pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) response in tomato. We speculate that the phenotypic differences observed between Arabidopsis and tomato/cotton/rice/maize Gβ knockouts do not necessarily reflect divergences in G protein-mediated defense mechanisms.
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Affiliation(s)
- Thi Thao Ninh
- Plant Genetic Engineering Laboratory, School of Agriculture and Food SciencesUniversity of QueenslandBrisbaneAustralia
- Department of Plant Biotechnology, Faculty of BiotechnologyVietnam National University of AgricultureHanoiVietnam
| | - Wei Gao
- State Key Laboratory of Cotton Biology, School of Life ScienceHenan UniversityKaifengChina
| | - Yuri Trusov
- Plant Genetic Engineering Laboratory, School of Agriculture and Food SciencesUniversity of QueenslandBrisbaneAustralia
| | - Jing‐Ruo Zhao
- State Key Laboratory of Cotton Biology, School of Life ScienceHenan UniversityKaifengChina
| | - Lu Long
- State Key Laboratory of Cotton Biology, School of Life ScienceHenan UniversityKaifengChina
| | - Chun‐Peng Song
- State Key Laboratory of Cotton Biology, School of Life ScienceHenan UniversityKaifengChina
| | - Jose Ramon Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food SciencesUniversity of QueenslandBrisbaneAustralia
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12
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Cao X, Xu P, Liu Y, Yang G, Liu M, Chen L, Cheng Y, Xu P, Miao L, Mao Z, Wang W, Kou S, Guo T, Yang HQ. Arabidopsis cryptochrome 1 promotes stomatal development through repression of AGB1 inhibition of SPEECHLESS DNA-binding activity. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:1967-1981. [PMID: 34469075 DOI: 10.1111/jipb.13168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
Cryptochromes are blue light photoreceptors that mediate various light responses in plants and mammals. The heterotrimeric G-protein is known to regulate various physiological processes in plants and mammals. In Arabidopsis, cryptochrome 1 (CRY1) and the G-protein β subunit AGB1 act antagonistically to regulate stomatal development. The molecular mechanism by which CRY1 and AGB1 regulate this process remains unknown. Here, we show that Arabidopsis CRY1 acts partially through AGB1, and AGB1 acts through SPEECHLESS (SPCH), a master transcription factor that drives stomatal initiation and proliferation, to regulate stomatal development. We demonstrate that AGB1 physically interacts with SPCH to block the bHLH DNA-binding domain of SPCH and inhibit its DNA-binding activity. Moreover, we demonstrate that photoexcited CRY1 represses the interaction of AGB1 with SPCH to release AGB1 inhibition of SPCH DNA-binding activity, leading to the expression of SPCH-target genes promoting stomatal development. Taken together, our results suggest that the mechanism by which CRY1 promotes stomatal development involves positive regulation of the DNA-binding activity of SPCH mediated by CRY1 inhibition of the AGB1-SPCH interaction. We propose that the antagonistic regulation of SPCH DNA-binding activity by CRY1 and AGB1 may allow plants to balance light and G-protein signaling and optimize stomatal density and pattern.
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Affiliation(s)
- Xiaoli Cao
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Pengbo Xu
- Department of Plant Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yao Liu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Guangqiong Yang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Minqing Liu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Li Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Yingyu Cheng
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Peng Xu
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Langxi Miao
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Zhilei Mao
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Wenxiu Wang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Shuang Kou
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Tongtong Guo
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Hong-Quan Yang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
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13
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Maruta N, Trusov Y, Jones AM, Botella JR. Heterotrimeric G Proteins in Plants: Canonical and Atypical Gα Subunits. Int J Mol Sci 2021; 22:11841. [PMID: 34769272 PMCID: PMC8584482 DOI: 10.3390/ijms222111841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
Heterotrimeric GTP-binding proteins (G proteins), consisting of Gα, Gβ and Gγ subunits, transduce signals from a diverse range of extracellular stimuli, resulting in the regulation of numerous cellular and physiological functions in Eukaryotes. According to the classic G protein paradigm established in animal models, the bound guanine nucleotide on a Gα subunit, either guanosine diphosphate (GDP) or guanosine triphosphate (GTP) determines the inactive or active mode, respectively. In plants, there are two types of Gα subunits: canonical Gα subunits structurally similar to their animal counterparts and unconventional extra-large Gα subunits (XLGs) containing a C-terminal domain homologous to the canonical Gα along with an extended N-terminal domain. Both Gα and XLG subunits interact with Gβγ dimers and regulator of G protein signalling (RGS) protein. Plant G proteins are implicated directly or indirectly in developmental processes, stress responses, and innate immunity. It is established that despite the substantial overall similarity between plant and animal Gα subunits, they convey signalling differently including the mechanism by which they are activated. This review emphasizes the unique characteristics of plant Gα subunits and speculates on their unique signalling mechanisms.
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Affiliation(s)
- Natsumi Maruta
- School of Agriculture and Food Sciences, University of Queensland, Brisbane 4072, Australia; (N.M.); (Y.T.)
| | - Yuri Trusov
- School of Agriculture and Food Sciences, University of Queensland, Brisbane 4072, Australia; (N.M.); (Y.T.)
| | - Alan M. Jones
- Departments of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
- Departments of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jose R. Botella
- School of Agriculture and Food Sciences, University of Queensland, Brisbane 4072, Australia; (N.M.); (Y.T.)
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14
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Chen G, Li Y, Qiao X, Duan W, Jin C, Cheng R, Wang J. Genome-wide survey of Gγ subunit gene family in eight Rosaceae and expression analysis of PbrGGs in pear (Pyrus bretschneideri). BMC PLANT BIOLOGY 2021; 21:471. [PMID: 34654373 PMCID: PMC8518290 DOI: 10.1186/s12870-021-03250-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 10/05/2021] [Indexed: 05/03/2023]
Abstract
BACKGROUND Heterotrimeric G-proteins, composed of Gα, Gβ and Gγ subunits, are important signal transmitters, mediating the cellular response to multiple stimuli in animals and plants. The Gγ subunit is an essential component of the G-protein, providing appropriate functional specificity to the heterotrimer complex and has been well studied in many species. However, the evolutionary history, expression pattern and functional characteristics of Gγ subunits has not been explored in the Rosaceae, representing many important fruit crops. RESULTS In this study, 35 Gγ subunit genes were identified from the eight species belonging to the Rosaceae family. Based on the structural gene characteristics, conserved protein motifs and phylogenetic analysis of the Gγ subunit genes, the genes were classified into three clades. Purifying selection was shown to play an important role in the evolution of Gγ subunit genes, while a recent whole-genome duplication event was the principal force determining the expansion of the Gγ subunit gene family in the subfamily Maloideae. Gγ subunit genes exhibited diverse spatiotemporal expression patterns in Chinese white pear, including fruit, root, ovary and bud, and under abiotic stress conditions, the relative expression of Gγ subunit genes were up-regulated or down-regulated. In addition, seven of the Gγ subunit proteins in pear were located on the plasma membrane, in the cytoplasm or nucleus. CONCLUSION Overall, this study of the Gγ subunit gene family in eight Rosaceae species provided useful information to better understand the evolution and expression of these genes and facilitated further exploration of their functions in these important crop plants.
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Affiliation(s)
- Guodong Chen
- College of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, China.
| | - Yang Li
- College of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, China
| | - Xin Qiao
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Weike Duan
- College of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, China
| | - Cong Jin
- College of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, China
| | - Rui Cheng
- Huai'an Key Laboratory for Facility Vegetables, Huaiyin Institute of Agricultural Sciences of Xuhuai Region of Jiangsu, Huai'an, 223001, China
| | - Jizhong Wang
- College of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, China
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15
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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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16
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Oligomerization of A. thaliana Heterotrimeric G Protein Subunits AGB1 and AGG2 In Vitro. Protein J 2020; 39:563-573. [PMID: 32772216 DOI: 10.1007/s10930-020-09914-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Plant heterotrimeric G proteins are a major group of signaling molecules involved in regulation of critical processes including stress adaptation, seed size, grain quality and immune responses. Despite an abundance of in situ functional studies; purification of the individual subunits of the plant heterotrimer for biophysical and structural characterization and for studies on their interactions are lacking. In this study cloning of the genes encoding the β subunit AGB1 of A. thaliana and its γ-subunits AGG1 and AGG2 using different E. coli expression vectors and screening of expression in several strains are reported. AGB1 could be expressed albeit at very low levels and in all cases it was accompanied by overexpression of E. coli chaperone proteins. AGG1 could only be detected in inclusion body fractions, whereas AGG2 was obtained in soluble fractions and was purified. Purified AGB1 and AGG2 subunits were shown to dimerize in vitro. Further characterization of AGG2 by small angle X-ray scattering measurements and by dynamic light scattering revealed that AGG2 formed homodimers with extended shape in solution. These results are also consistent with those from circular dichroism spectroscopy which yielded 39.4% helical and 50% random coil content for AGG2. This is the first study showing heterologous expression of a plant heterotrimeric G protein β subunit individually and presenting its interaction with a plant γ-subunit in vitro. Results also show that the AGG2 subunit has a disordered structure, which would account for its role in diverse interactions for establishing selectivity in signal propagation.
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17
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JA-Induced Endocytosis of AtRGS1 Is Involved in G-Protein Mediated JA Responses. Int J Mol Sci 2019; 20:ijms20153779. [PMID: 31382426 PMCID: PMC6695760 DOI: 10.3390/ijms20153779] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/27/2019] [Accepted: 07/29/2019] [Indexed: 12/17/2022] Open
Abstract
Arabidopsis heterotrimeric G proteins regulate diverse plant growth and defense processes by coupling to 7TM AtRGS1 proteins. Although G protein mutants display alterations in response to multiple plant hormones, the underlying mechanism by which G proteins participate in the regulation of hormone responses remains elusive. Here, we show that genetic disruption of Gα and Gβ subunits results in reduced sensitivity to JA treatment. Furthermore, using confocal microscopy, VA-TIRFM, and FRET-FLIM, we provide evidence that stimulation by JA induces phosphorylation- and C-terminus-dependent endocytosis of AtRGS1, which then promotes dissociation of AtRGS1 from AtGPA1. In addition, SPT analysis reveals that JA treatment affects the diffusion dynamics of AtRGS1 and AtRGS1-ΔCt. Taken together, these findings suggest that the JA signal activates heterotrimeric G proteins through the endocytosis of AtRGS1 and dissociation of AtRGS1 from AtGPA1, thus providing valuable insight into the mechanisms of how the G protein system perceives and transduces phytohormone signals.
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18
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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: 13] [Impact Index Per Article: 2.6] [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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19
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Biswal AK, McConnell EW, Werth EG, Lo SF, Yu SM, Hicks LM, Jones AM. The Nucleotide-Dependent Interactome of Rice Heterotrimeric G-Protein α -Subunit. Proteomics 2019; 19:e1800385. [PMID: 30866160 DOI: 10.1002/pmic.201800385] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 02/12/2019] [Indexed: 11/09/2022]
Abstract
The rice heterotrimeric G-protein complex, a guanine-nucleotide-dependent on-off switch, mediates vital cellular processes and responses to biotic and abiotic stress. Exchange of bound GDP (resting state) for GTP (active state) is spontaneous in plants including rice and thus there is no need for promoting guanine nucleotide exchange in vivo as a mechanism for regulating the active state of signaling as it is well known for animal G signaling. As such, a master regulator controlling the G-protein activation state is unknown in plants. Therefore, an ab initio approach is taken to discover candidate regulators. The rice Gα subunit (RGA1) is used as bait to screen for nucleotide-dependent protein partners. A total of 264 proteins are identified by tandem mass spectrometry of which 32 were specific to the GDP-bound inactive state and 22 specific to the transition state. Approximately, 10% are validated as previously identified G-protein interactors.
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Affiliation(s)
- Akshaya Kumar Biswal
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Evan Wesley McConnell
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Emily Grace Werth
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Shuen-Fang Lo
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan, China
| | - Su-May Yu
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan, China
| | - Leslie M Hicks
- Department of Chemistry, 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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20
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Dong H, Yan S, Liu J, Liu P, Sun J. TaCOLD1 defines a new regulator of plant height in bread wheat. PLANT BIOTECHNOLOGY JOURNAL 2019; 17:687-699. [PMID: 30183124 PMCID: PMC6381784 DOI: 10.1111/pbi.13008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 08/14/2018] [Accepted: 08/23/2018] [Indexed: 05/21/2023]
Abstract
Plant height is among the most important agronomic traits that influence crop yield. However, in addition to the Rht-1 alleles, the molecular basis of plant height in bread wheat remains largely unclear. Based on wheat gene expression profiling analysis, we identify a light-regulated gene from bread wheat, designated as TaCOLD1, whose encoding protein is homologous to cold sensor COLD1 in rice. We show that TaCOLD1 protein is localized to the endoplasmic reticulum (ER) and plasma membrane. Phenotypic analyses show that overexpression of a mutated form of TaCOLD1 (M187K) in bread wheat cultivar Kenong199 (Rht-B1b) background resulted in an obvious reduction in plant height. Further, we demonstrate that the hydrophilic loop of TaCOLD1 (residues 178-296) can interact with TaGα-7A (the α subunit of heterotrimeric G protein) protein but not TaGα-1B, and the mutation (M187K) in TaCOLD1 remarkably enhances its interaction with TaGα-7A. Physical interaction analyses show that the C-terminal region of TaGα-7A, which is lacking in the TaGα-1B protein, is necessary for its interaction with TaCOLD1. Intriguingly, the C-terminal region of TaGα-7A is also physically associated with the TaDEP1 protein (an atypical Gγ subunit). Significantly, we discover that TaCOLD1 and mTaCOLD1 (M187K) can interfere with the physical association between TaGα-7A and TaDEP1. Together, this study reveals that TaCOLD1 acts as a novel regulator of plant height through interfering with the formation of heterotrimeric G protein complex in bread wheat and is a valuable target for the engineering of wheat plant architecture.
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Affiliation(s)
- Huixue Dong
- National Key Facility for Crop Gene Resources and Genetic ImprovementInstitute of Crop SciencesChinese Academy of Agricultural SciencesBeijingChina
| | - Suli Yan
- National Key Facility for Crop Gene Resources and Genetic ImprovementInstitute of Crop SciencesChinese Academy of Agricultural SciencesBeijingChina
| | - Jie Liu
- National Key Facility for Crop Gene Resources and Genetic ImprovementInstitute of Crop SciencesChinese Academy of Agricultural SciencesBeijingChina
| | - Pan Liu
- National Key Facility for Crop Gene Resources and Genetic ImprovementInstitute of Crop SciencesChinese Academy of Agricultural SciencesBeijingChina
| | - Jiaqiang Sun
- National Key Facility for Crop Gene Resources and Genetic ImprovementInstitute of Crop SciencesChinese Academy of Agricultural SciencesBeijingChina
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21
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Xu P, Lian H, Xu F, Zhang T, Wang S, Wang W, Du S, Huang J, Yang HQ. Phytochrome B and AGB1 Coordinately Regulate Photomorphogenesis by Antagonistically Modulating PIF3 Stability in Arabidopsis. MOLECULAR PLANT 2019; 12:229-247. [PMID: 30576873 DOI: 10.1016/j.molp.2018.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 11/22/2018] [Accepted: 12/05/2018] [Indexed: 06/09/2023]
Abstract
Phytochrome B (phyB), the primary red light photoreceptor, promotes photomorphogenesis in Arabidopsis by interacting with the basic helix-loop-helix transcriptional factor PIF3 and inducing its phosphorylation and degradation. Heterotrimeric G proteins are known to regulate various developmental processes in plants and animals. In Arabidopsis, the G-protein β subunit AGB1 is known to repress photomorphogenesis. However, whether and how phyB and AGB1 coordinately regulate photomorphogenesis are largely unknown. Here we show that phyB physically interacts with AGB1 in a red light-dependent manner and that AGB1 interacts directly with PIF3. Moreover, we demonstrate that the AGB1-PIF3 interaction inhibits the association of PIF3 with phyB, leading to reduced phosphorylation and degradation of PIF3, whereas the phyB-AGB1 interaction represses the association of PIF3 with AGB1, resulting in enhanced phosphorylation and degradation of PIF3. Our results suggest that phyB and AGB1 antagonistically regulate PIF3 stability by dynamically interacting with each other and PIF3. This dynamic mechanism may allow plants to balance phyB and G-protein signaling to optimize photomorphogenesis.
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Affiliation(s)
- Pengbo Xu
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hongli Lian
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, 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
| | - Ting Zhang
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Sheng Wang
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wenxiu Wang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Shasha Du
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jirong Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Hong-Quan Yang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China.
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22
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Phenotypic and genome-wide association with the local environment of Arabidopsis. Nat Ecol Evol 2019; 3:274-285. [PMID: 30643246 DOI: 10.1038/s41559-018-0754-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 11/15/2018] [Indexed: 12/26/2022]
Abstract
The environment imposes critical selective forces on all living organisms, and the sessile nature of plants makes them particularly useful for investigating the relationship between genetic variation and environmental adaptation. In the model plant Arabidopsis thaliana, extensive information on phenotypic and genotypic variation is available, but comparable information on environmental variation within the native range of the species is lacking. Here, we compile 204 geoclimatic variables to describe the local environments of Arabidopsis accessions with known collection sites encompassing a wide geo-environmental range, and fully sequenced genomes from the 1001 Genomes Project. We identify candidate adaptive genetic variation associated with these environmental variables, and validate this approach through comparison with previous experimental studies, and by targeted confirmation of a role of the heterotrimeric G-protein γ subunit, AGG3, in cold tolerance, as newly predicted from our environmental genome wide association study (GWAS). To facilitate identification of adaptive variation, we created Arabidopsis CLIMtools : interactive web-based databases of the environment × genome associations and correlations between the local environments and 131 phenotypes compiled from previous experimental GWASs. Our study presents an extensive analysis of the local environments, landscape genomics and phenotypic variation of Arabidopsis, and illustrates how 'in silico GWAS' approaches can inform and complement experimental phenomics studies.
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23
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Characterization of Heterotrimeric G Protein γ4 Subunit in Rice. Int J Mol Sci 2018; 19:ijms19113596. [PMID: 30441812 PMCID: PMC6274817 DOI: 10.3390/ijms19113596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 11/05/2018] [Accepted: 11/09/2018] [Indexed: 11/25/2022] Open
Abstract
Heterotrimeric G proteins are the molecule switch that transmits information from external signals to intracellular target proteins in mammals and yeast cells. In higher plants, heterotrimeric G proteins regulate plant architecture. Rice harbors one canonical α subunit gene (RGA1), four extra-large GTP-binding protein genes (XLGs), one canonical β-subunit gene (RGB1), and five γ-subunit genes (tentatively designated RGG1, RGG2, RGG3/GS3/Mi/OsGGC1, RGG4/DEP1/DN1/qPE9-1/OsGGC3, and RGG5/OsGGC2) as components of the heterotrimeric G protein complex. Among the five γ-subunit genes, RGG1 encodes the canonical γ-subunit, RGG2 encodes a plant-specific type of γ-subunit with additional amino acid residues at the N-terminus, and the remaining three γ-subunit genes encode atypical γ-subunits with cysteine-rich C-termini. We characterized the RGG4/DEP1/DN1/qPE9-1/OsGGC3 gene product Gγ4 in the wild type (WT) and truncated protein Gγ4∆Cys in the RGG4/DEP1/DN1/qPE9-1/OsGGC3 mutant, Dn1-1, as littele information regarding the native Gγ4 and Gγ4∆Cys proteins is currently available. Based on liquid chromatography-tandem mass spectrometry analysis, immunoprecipitated Gγ4 candidates were confirmed as actual Gγ4. Similar to α-(Gα) and β-subunits (Gβ), Gγ4 was enriched in the plasma membrane fraction and accumulated in the developing leaf sheath. As RGG4/DEP1/DN1/qPE9-1/OsGGC3 mutants exhibited dwarfism, tissues that accumulated Gγ4 corresponded to the abnormal tissues observed in RGG4/DEP1/DN1/qPE9-1/OsGGC3 mutants.
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24
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Nishiyama A, Matsuta S, Chaya G, Itoh T, Miura K, Iwasaki Y. Identification of Heterotrimeric G Protein γ3 Subunit in Rice Plasma Membrane. Int J Mol Sci 2018; 19:ijms19113591. [PMID: 30441767 PMCID: PMC6274724 DOI: 10.3390/ijms19113591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/07/2018] [Accepted: 11/07/2018] [Indexed: 12/02/2022] Open
Abstract
Heterotrimeric G proteins are important molecules for regulating plant architecture and transmitting external signals to intracellular target proteins in higher plants and mammals. The rice genome contains one canonical α subunit gene (RGA1), four extra-large GTP-binding protein genes (XLGs), one canonical β subunit gene (RGB1), and five γ subunit genes (tentatively named RGG1, RGG2, RGG3/GS3/Mi/OsGGC1, RGG4/DEP1/DN1/OsGGC3, and RGG5/OsGGC2). RGG1 encodes the canonical γ subunit; RGG2 encodes the plant-specific type of γ subunit with additional amino acid residues at the N-terminus; and the remaining three γ subunit genes encode the atypical γ subunits with cysteine abundance at the C-terminus. We aimed to identify the RGG3/GS3/Mi/OsGGC1 gene product, Gγ3, in rice tissues using the anti-Gγ3 domain antibody. We also analyzed the truncated protein, Gγ3∆Cys, in the RGG3/GS3/Mi/OsGGC1 mutant, Mi, using the anti-Gγ3 domain antibody. Based on nano-liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, the immunoprecipitated Gγ3 candidates were confirmed to be Gγ3. Similar to α (Gα) and β subunits (Gβ), Gγ3 was enriched in the plasma membrane fraction, and accumulated in the flower tissues. As RGG3/GS3/Mi/OsGGC1 mutants show the characteristic phenotype in flowers and consequently in seeds, the tissues that accumulated Gγ3 corresponded to the abnormal tissues observed in RGG3/GS3/Mi/OsGGC1 mutants.
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Affiliation(s)
- Aki Nishiyama
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-Town, Fukui 910-1195, Japan.
| | - Sakura Matsuta
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-Town, Fukui 910-1195, Japan.
| | - Genki Chaya
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-Town, Fukui 910-1195, Japan.
| | - Takafumi Itoh
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-Town, Fukui 910-1195, Japan.
| | - Kotaro Miura
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-Town, Fukui 910-1195, Japan.
| | - Yukimoto Iwasaki
- Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-Town, Fukui 910-1195, Japan.
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25
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Yu Y, Assmann SM. Inter-relationships between the heterotrimeric Gβ subunit AGB1, the receptor-like kinase FERONIA, and RALF1 in salinity response. PLANT, CELL & ENVIRONMENT 2018; 41:2475-2489. [PMID: 29907954 PMCID: PMC6150805 DOI: 10.1111/pce.13370] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 06/04/2018] [Accepted: 06/08/2018] [Indexed: 05/06/2023]
Abstract
Plant heterotrimeric G proteins modulate numerous developmental stress responses. Recently, receptor-like kinases (RLKs) have been implicated as functioning with G proteins and may serve as plant G-protein-coupled-receptors. The RLK FERONIA (FER), in the Catharantus roseus RLK1-like subfamily, is activated by a family of polypeptides called rapid alkalinization factors (RALFs). We previously showed that the Arabidopsis G protein β subunit, AGB1, physically interacts with FER, and that RALF1 regulation of stomatal movement through FER requires AGB1. Here, we investigated genetic interactions of AGB1 and FER in plant salinity response by comparing salt responses in the single and double mutants of agb1 and fer. We show that AGB1 and FER act additively or synergistically depending on the conditions of the NaCl treatments. We further show that the synergism likely occurs through salt-induced ROS production. In addition, we show that RALF1 enhances salt toxicity through increasing Na+ accumulation and decreasing K+ accumulation rather than by inducing ROS production, and that the RALF1 effect on salt response occurs in an AGB1-independent manner. Our results indicate that RLK epistatic relationships are not fixed, as AGB1 and FER display different genetic relationships to RALF1 in stomatal versus salinity responses.
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Affiliation(s)
| | - Sarah M. Assmann
- To whom correspondence should be addressed: , tel. 814-863-9579, fax. 814-865-9131
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26
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Chakravorty D, Yu Y, Assmann SM. A kinase-dead version of FERONIA receptor-like kinase has dose-dependent impacts on rosette morphology and RALF1-mediated stomatal movements. FEBS Lett 2018; 592:3429-3437. [PMID: 30207378 PMCID: PMC6205910 DOI: 10.1002/1873-3468.13249] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/31/2018] [Accepted: 09/05/2018] [Indexed: 12/18/2022]
Abstract
The receptor-like kinase FERONIA (FER) pleiotropically affects plant reproduction, development, and stress tolerance. We recently showed that the FER ligand RALF1 promotes stomatal closure and inhibits stomatal opening in a G-protein-dependent manner. FER responses have been designated as kinase-dependent or kinase-independent, based largely on fer complementation assays employing a kinase-dead FERK565R. Our quantification of FERK565R-GFP transcript and FERK565R-GFP protein in fer complementation lines reveal that, even within individual complementation lines, different levels of FERK565R expression prevail. FERK565R-GFP expression comparable to that of FER in Col-0 plants fail to elicit complementation of either fer rosette phenotypes or RALF1-elicited stomatal movements, whereas overexpression levels of FERK565R-GFP result in complementation. These results suggest possible alternative interpretations of previous conclusions regarding kinase-independent FER signaling.
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Affiliation(s)
- David Chakravorty
- Biology Department, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA, USA
| | - Yunqing Yu
- Biology Department, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA, USA
| | - Sarah M Assmann
- Biology Department, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA, USA
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27
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Wang S, Xie K, Xu G, Zhou H, Guo Q, Wu J, Liao Z, Liu N, Wang Y, Liu Y. Plant G proteins interact with endoplasmic reticulum luminal protein receptors to regulate endoplasmic reticulum retrieval. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2018; 60:541-561. [PMID: 29573168 DOI: 10.1111/jipb.12648] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
Maintaining endoplasmic reticulum (ER) homeostasis is essential for the production of biomolecules. ER retrieval, i.e., the retrograde transport of compounds from the Golgi to the ER, is one of the pathways that ensures ER homeostasis. However, the mechanisms underlying the regulation of ER retrieval in plants remain largely unknown. Plant ERD2-like proteins (ERD2s) were recently suggested to function as ER luminal protein receptors that mediate ER retrieval. Here, we demonstrate that heterotrimeric G protein signaling is involved in ERD2-mediated ER retrieval. We show that ERD2s interact with the heterotrimeric G protein Gα and Gγ subunits at the Golgi. Silencing of Gα, Gβ, or Gγ increased the retention of ER luminal proteins. Furthermore, overexpression of Gα, Gβ, or Gγ caused ER luminal proteins to escape from the ER, as did the co-silencing of ERD2a and ERD2b. These results suggest that G proteins interact with ER luminal protein receptors to regulate ER retrieval.
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Affiliation(s)
- Shanshan Wang
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ke Xie
- Advanced Biotechnology and Application Research Center, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Guoyong Xu
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan 430072, China
| | - Huarui Zhou
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiang Guo
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jingyi Wu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zengwei Liao
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Na Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yan Wang
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
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28
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Pandey S, Vijayakumar A. Emerging themes in heterotrimeric G-protein signaling in plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 270:292-300. [PMID: 29576082 DOI: 10.1016/j.plantsci.2018.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/18/2018] [Accepted: 03/01/2018] [Indexed: 05/28/2023]
Abstract
Heterotrimeric G-proteins are key signaling components involved during the regulation of a multitude of growth and developmental pathways in all eukaryotes. Although the core proteins (Gα, Gβ, Gγ subunits) and their basic biochemistries are conserved between plants and non-plant systems, seemingly different inherent properties of specific components, altered wirings of G-protein network architectures, and the presence of novel receptors and effector proteins make plant G-protein signaling mechanisms somewhat distinct from the well-established animal paradigm. G-protein research in plants is getting a lot of attention recently due to the emerging roles of these proteins in controlling many agronomically important traits. New findings on both canonical and novel G-protein components and their conserved and unique signaling mechanisms are expected to improve our understanding of this important module in affecting critical plant growth and development pathways and eventually their utilization to produce plants for the future needs. In this review, we briefly summarize what is currently known in plant G-protein research, describe new findings and how they are changing our perceptions of the field, and discuss important issues that still need to be addressed.
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Affiliation(s)
- Sona Pandey
- Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, MO, 63132, USA.
| | - Anitha Vijayakumar
- Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, MO, 63132, USA
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29
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BRI1 and BAK1 interact with G proteins and regulate sugar-responsive growth and development in Arabidopsis. Nat Commun 2018; 9:1522. [PMID: 29670153 PMCID: PMC5906681 DOI: 10.1038/s41467-018-03884-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/20/2018] [Indexed: 12/24/2022] Open
Abstract
Sugars function as signal molecules to regulate growth, development, and gene expression in plants, yeasts, and animals. A coordination of sugar availability with phytohormone signals is crucial for plant growth and development. The molecular link between sugar availability and hormone-dependent plant growth are largely unknown. Here we report that BRI1 and BAK1 are involved in sugar-responsive growth and development. Glucose influences the physical interactions and phosphorylations of BRI1 and BAK1 in a concentration-dependent manner. BRI1 and BAK1 physically interact with G proteins that are essential for mediating sugar signaling. Biochemical data show that BRI1 can phosphorylate G protein β subunit and γ subunits, and BAK1 can phosphorylate G protein γ subunits. Genetic analyses suggest that BRI1 and BAK1 function in a common pathway with G-protein subunits to regulate sugar responses. Thus, our findings reveal an important genetic and molecular mechanism by which BR receptors associate with G proteins to regulate sugar-responsive growth and development. G-proteins regulate sugar-responsive growth in plants. Here the authors show that brassinosteroid (BR) signaling is also involved in sugar responses and present evidence that the BR receptor BRI1 and its co-receptor BAK1 can phosphorylate G-protein subunits to regulate sugar signaling in Arabidopsis.
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30
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Leppyanen IV, Kirienko AN, Lobov AA, Dolgikh EA. Differential proteome analysis of pea roots at the early stages of symbiosis with nodule bacteria. Vavilovskii Zhurnal Genet Selektsii 2018. [DOI: 10.18699/vj18.347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
In this paper, we have analyzed changes in the proteomic spectrum of pea Pisum sativum L. roots during inoculation with rhizobial bacteria with the aim of revealing new regulators of symbiosis development. To study the changes in the proteome spectrum of pea roots, a differential twodimensional (2-D) electrophoresis was performed using fluorescent labels Cy2 and Cy5. The images obtained made it possible to identify differences between the control variant (uninoculated roots) and the root variant after inoculation with Rhizobium leguminosarum bv. viciae RCAM 1026 (24 hours after treatment). 20 proteins were revealed and identified, the synthesis of which was enhanced during the inoculation of pea roots by nodule bacteria. To identify the proteins, a mass spectrometric analysis of tryptic peptides was performed on a quadrupole-time-of-flight mass spectrometer combined with a high-performance liquid chromatograph. Among such proteins, the beta-subunit of the G protein and the disulfide isomerase/phospholipase C were first found, whose function can be related to the signal regulation of symbiosis. This indicates that G-proteins and phospholipases can play a key role in the development of early stages of symbiosis in peas. Further experiments are expected to show whether the beta-subunit of the G protein interacts with the receptors to Nod factors, and how this affects the further signaling. Other proteins that might be interesting were annexin D8 and D1, protein kinase interacting with calcinerin B, actin-binding protein profilin, GTP-binding protein Ran1. They may be involved in the regulation of reactions with calcium, the reorganization of the actin cytoskeleton and other important processes in plants. The study of the role of such regulatory proteins will later become the basis for understanding the complex system of signal regulation, which is activated in pea plants by interaction with nodule bacteria.
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Affiliation(s)
- I. V. Leppyanen
- All-Russian Scientific Research Institute of Agricultural Microbiology
| | - A. N. Kirienko
- All-Russian Scientific Research Institute of Agricultural Microbiology
| | - A. A. Lobov
- Resource Center “Development of Molecular and Cellular Technologies”, Science Park, St. Petersburg State University
| | - E. A. Dolgikh
- All-Russian Scientific Research Institute of Agricultural Microbiology
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31
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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: 64] [Impact Index Per Article: 10.7] [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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32
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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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33
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Kumar R, Sharma A, Chandel I, Bisht NC. Pattern of expression and interaction specificity of multiple G-protein beta (Gβ) subunit isoforms with their potential target proteins reveal functional dominance of BjuGβ1 in the allotetraploid Brassica juncea. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 118:22-30. [PMID: 28603081 DOI: 10.1016/j.plaphy.2017.05.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/17/2017] [Accepted: 05/25/2017] [Indexed: 06/07/2023]
Abstract
Heterotrimeric G-protein, consisting Gα, Gβ and Gγ subunits, interacts with various upstream and downstream effector (target) proteins to regulate a large array of conserved and species-specific biological functions. The targets of G-protein components are recently reported in model plant Arabidopsis thaliana; however limited information is available from crop species. In this study, we utilized yeast two-hybrid (Y2H) assay to screen the diversity of interacting partners of multiple Gβ subunit isoforms from allotetraploid Brassica juncea, a globally important oilseed and vegetable crop. The three BjuGβ genes (BjuGβ1-3), resulted from whole genome triplication event in Brassica lineage, showed distinct expression profile during plant developmental stages with maximal transcript abundance during reproductive stages. Protein-protein interaction of three BjuGβ proteins (bait) against the Y2H cDNA library (prey) identified a total of 14 and 1 non-redundant targets for BjuGβ1 and BjuGβ2, whereas BjuGβ3 screening surprisingly did not yield any genuine target, thereby suggesting functional dominance of BjuGβ1. The triplicated BjuGβ isoforms showed a high degree of interaction strength and specificity with the identified target proteins, which are known to be involved in diverse biological functions in plants. qRT-PCR analysis further indicated that the expression of BjuGβ-target genes was developmentally regulated under various tissue types studied and showed a high degree of co-expression pattern with the BjuGβ genes, particularly during flower and silique development in B. juncea. Taken together, our data provides novel insights on pattern of expression and interaction specificity governing functional divergence of multiple Gβ subunit proteins in polyploid B. juncea.
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Affiliation(s)
- Roshan Kumar
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Aprajita Sharma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Ishita Chandel
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Naveen C Bisht
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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Wendt T, Holme I, Dockter C, Preuß A, Thomas W, Druka A, Waugh R, Hansson M, Braumann I. HvDep1 Is a Positive Regulator of Culm Elongation and Grain Size in Barley and Impacts Yield in an Environment-Dependent Manner. PLoS One 2016; 11:e0168924. [PMID: 28005988 PMCID: PMC5179111 DOI: 10.1371/journal.pone.0168924] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 12/08/2016] [Indexed: 11/19/2022] Open
Abstract
Heterotrimeric G proteins are intracellular membrane-attached signal transducers involved in various cellular processes in both plants and animals. They consist of three subunits denoted as α, β and γ. The γ-subunits of the so-called AGG3 type, which comprise a transmembrane domain, are exclusively found in plants. In model species, these proteins have been shown to participate in the control of plant height, branching and seed size and could therefore impact the harvestable yield of various crop plants. Whether AGG3-type γ-subunits influence yield in temperate cereals like barley and wheat remains unknown. Using a transgenic complementation approach, we show here that the Scottish malting barley cultivar (cv.) Golden Promise carries a loss-of-function mutation in HvDep1, an AGG3-type subunit encoding gene that positively regulates culm elongation and seed size in barley. Somewhat intriguingly, agronomic field data collected over a 12-year period reveals that the HvDep1 loss-of-function mutation in cv. Golden Promise has the potential to confer either a significant increase or decrease in harvestable yield depending on the environment. Our results confirm the role of AGG3-type subunit-encoding genes in shaping plant architecture, but interestingly also indicate that the impact HvDep1 has on yield in barley is both genotypically and environmentally sensitive. This may explain why widespread exploitation of variation in AGG3-type subunit-encoding genes has not occurred in temperate cereals while in rice the DEP1 locus is widely exploited to improve harvestable yield.
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Affiliation(s)
- Toni Wendt
- Carlsberg Research Laboratory, Copenhagen, Denmark
| | - Inger Holme
- Department of Molecular Biology and Genetics, Faculty of Science and Technology, Aarhus University, Slagelse, Denmark
| | | | - Aileen Preuß
- Carlsberg Research Laboratory, Copenhagen, Denmark
| | - William Thomas
- James Hutton Institute, Invergowrie, Dundee, United Kingdom
| | - Arnis Druka
- James Hutton Institute, Invergowrie, Dundee, United Kingdom
| | - Robbie Waugh
- James Hutton Institute, Invergowrie, Dundee, United Kingdom
- Division of Plant Sciences, The University of Dundee, Invergowrie, Dundee, United Kingdom
| | - Mats Hansson
- Department of Biology, Lund University, Lund, Sweden
| | - Ilka Braumann
- Carlsberg Research Laboratory, Copenhagen, Denmark
- * E-mail:
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35
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Stateczny D, Oppenheimer J, Bommert P. G protein signaling in plants: minus times minus equals plus. CURRENT OPINION IN PLANT BIOLOGY 2016; 34:127-135. [PMID: 27875794 DOI: 10.1016/j.pbi.2016.11.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 10/31/2016] [Accepted: 11/01/2016] [Indexed: 05/09/2023]
Abstract
Heterotrimeric G proteins are key regulators in the transduction of extracellular signals both in animals and plants. In plants, heterotrimeric G protein signaling plays essential roles in development and in response to biotic and abiotic stress. However, over the last decade it has become clear that plants have unique mechanisms of G protein signaling. Although plants share most of the core components of heterotrimeric G proteins, some of them exhibit unusual properties compared to their animal counterparts. In addition, plants do not share functional GPCRs. Therefore the well-established paradigm of the animal G protein signaling cycle is not applicable in plants. In this review, we summarize recent insights into these unique mechanisms of G protein signaling in plants with special focus on the evident potential of G protein signaling as a target to modify developmental and physiological parameters important for yield increase.
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Affiliation(s)
- Dave Stateczny
- University of Hamburg, Biozentrum Klein Flottbek, Department of Developmental Biology, Ohnhorststr. 18, D-22609 Hamburg, Germany
| | - Jara Oppenheimer
- University of Hamburg, Biozentrum Klein Flottbek, Department of Developmental Biology, Ohnhorststr. 18, D-22609 Hamburg, Germany
| | - Peter Bommert
- University of Hamburg, Biozentrum Klein Flottbek, Department of Developmental Biology, Ohnhorststr. 18, D-22609 Hamburg, Germany.
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36
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Brenya E, Trusov Y, Dietzgen RG, Botella JR. Heterotrimeric G-proteins facilitate resistance to plant pathogenic viruses in Arabidopsis thaliana (L.) Heynh. PLANT SIGNALING & BEHAVIOR 2016; 11:e1212798. [PMID: 27454415 PMCID: PMC5022408 DOI: 10.1080/15592324.2016.1212798] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Heterotrimeric G-proteins, consisting of Gα, Gβ and Gγ subunits, are important signal transducers in eukaryotes. In plants, G-protein-mediated signaling contributes to defense against a range of fungal and bacterial pathogens. Here we studied response of G-protein-deficient mutants to ssRNA viruses representing 2 different families: Cucumber mosaic virus (CMV) (Bromoviridae) and Turnip mosaic virus (TuMV) (Potyviridae). We found that development of spreading necrosis on infected plants was suppressed in the Gβ-deficient mutant (agb1-2) compared to wild type and Gα-deficient mutant (gpa1-4). In accordance, ion leakage caused by viral infection was also significantly reduced in agb1-2 compared to wild type and gpa1-4. Nevertheless, both viruses replicated better in agb1-2 plants, while gpa1-4 was similar to wild type. Analysis of pathogenesis-related genes showed that Gβ negatively regulated salicylic acid, jasmonic acid and abscisic acid marker genes during CMV and TuMV infections. Interestingly, analysis of salicylic acid deficient transgenic plants indicated that salicylic acid did not affect resistance against these viruses and did not influence the Gβ-mediated defense response. We conclude that heterotrimeric G-proteins play a positive role in defense against viral pathogens probably by promoting cell death.
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Affiliation(s)
- Eric Brenya
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Yuri Trusov
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Ralf Georg Dietzgen
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland, Australia
| | - José Ramón Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland, Australia
- CONTACT José Ramón Botella
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Xu Q, Zhao M, Wu K, Fu X, Liu Q. Emerging insights into heterotrimeric G protein signaling in plants. J Genet Genomics 2016; 43:495-502. [DOI: 10.1016/j.jgg.2016.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/23/2016] [Accepted: 06/24/2016] [Indexed: 12/23/2022]
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Trusov Y, Botella JR. Plant G-Proteins Come of Age: Breaking the Bond with Animal Models. Front Chem 2016; 4:24. [PMID: 27252940 PMCID: PMC4877378 DOI: 10.3389/fchem.2016.00024] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/04/2016] [Indexed: 11/29/2022] Open
Abstract
G-proteins are universal signal transducers mediating many cellular responses. Plant G-protein signaling has been modeled on the well-established animal paradigm but accumulated experimental evidence indicates that G-protein-dependent signaling in plants has taken a very different evolutionary path. Here we review the differences between plant and animal G-proteins reported over past two decades. Most importantly, while in animal systems the G-protein signaling cycle is activated by seven transmembrane-spanning G-protein coupled receptors, the existence of these type of receptors in plants is highly controversial. Instead plant G-proteins have been proven to be functionally associated with atypical receptors such as the Arabidopsis RGS1 and a number of receptor-like kinases. We propose that, instead of the GTP/GDP cycle used in animals, plant G-proteins are activated/de-activated by phosphorylation/de-phosphorylation. We discuss the need of a fresh new look at these signaling molecules and provide a hypothetical model that departs from the accepted animal paradigm.
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Affiliation(s)
- Yuri Trusov
- School of Agriculture and Food Sciences, University of Queensland Brisbane, QLD, Australia
| | - José R Botella
- School of Agriculture and Food Sciences, University of Queensland Brisbane, QLD, Australia
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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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Miller JC, Chezem WR, Clay NK. Ternary WD40 Repeat-Containing Protein Complexes: Evolution, Composition and Roles in Plant Immunity. FRONTIERS IN PLANT SCIENCE 2016; 6:1108. [PMID: 26779203 PMCID: PMC4703829 DOI: 10.3389/fpls.2015.01108] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 11/23/2015] [Indexed: 05/18/2023]
Abstract
Plants, like mammals, rely on their innate immune system to perceive and discriminate among the majority of their microbial pathogens. Unlike mammals, plants respond to this molecular dialog by unleashing a complex chemical arsenal of defense metabolites to resist or evade pathogen infection. In basal or non-host resistance, plants utilize signal transduction pathways to detect "non-self," "damaged-self," and "altered-self"- associated molecular patterns and translate these "danger" signals into largely inducible chemical defenses. The WD40 repeat (WDR)-containing proteins Gβ and TTG1 are constituents of two independent ternary protein complexes functioning at opposite ends of a plant immune signaling pathway. They are also encoded by single-copy genes that are ubiquitous in higher plants, implying the limited diversity and functional conservation of their respective complexes. In this review, we summarize what is currently known about the evolutionary history of these WDR-containing ternary complexes, their repertoire and combinatorial interactions, and their downstream effectors and pathways in plant defense.
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Affiliation(s)
- Jimi C. Miller
- Department of Molecular Biophysics and Biochemistry, Yale UniversityNew Haven, CT, USA
| | - William R. Chezem
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew Haven, CT, USA
| | - Nicole K. Clay
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew Haven, CT, USA
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41
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Maruta N, Trusov Y, Botella JR. Yeast Three-Hybrid System for the Detection of Protein-Protein Interactions. Methods Mol Biol 2016; 1363:145-154. [PMID: 26577787 DOI: 10.1007/978-1-4939-3115-6_12] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Protein-protein interaction studies provide useful insights into biological processes taking place within the living cell. A number of techniques are available to unravel large structural protein complexes, functional protein modules, and temporary protein associations occurring during signal transduction. The choice of method depends on the nature of the proteins and the interaction being studied. Here we present an optimized and simplified yeast three-hybrid method for analysis of protein interactions involving three components.
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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
| | - Jose R Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.
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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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43
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Shi W, Zeng Q, Kunkel BN, Running MP. Arabidopsis Rab Geranylgeranyltransferases Demonstrate Redundancy and Broad Substrate Specificity in Vitro. J Biol Chem 2015; 291:1398-410. [PMID: 26589801 DOI: 10.1074/jbc.m115.673491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Indexed: 11/06/2022] Open
Abstract
Posttranslational lipid modifications mediate the membrane attachment of Rab GTPases, facilitating their function in regulating intracellular vesicular trafficking. In Arabidopsis, most Rab GTPases have two C-terminal cysteines and potentially can be double-geranylgeranylated by heterodimeric Rab geranylgeranyltransferases (Rab-GGTs). Genes encoding two putative α subunits and two putative β subunits of Rab-GGTs have been annotated in the Arabidopsis thaliana genome, but little is known about Rab-GGT activity in Arabidopsis. In this study, we demonstrate that four different heterodimers can be formed between putative Arabidopsis Rab-GGT α subunits RGTA1/RGTA2 and β subunits RGTB1/RGTB2, but only RGTA1·RGTB1 and RGTA1·RGTB2 exhibit bona fide Rab-GGT activity, and they are biochemically redundant in vitro. We hypothesize that RGTA2 function might be disrupted by a 12-amino acid insertion in a conserved motif. We present evidence that Arabidopsis Rab-GGTs may have preference for prenylation of C-terminal cysteines in particular positions. We also demonstrate that Arabidopsis Rab-GGTs can not only prenylate a great variety of Rab GTPases in the presence of Rab escort protein but, unlike Rab-GGT in yeast and mammals, can also prenylate certain non-Rab GTPases independently of Rab escort protein. Our findings may help to explain some of the phenotypes of Arabidopsis protein prenyltransferase mutants.
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Affiliation(s)
- Wan Shi
- From the Department of Biology, Washington University, Saint Louis, Missouri 63130
| | - Qin Zeng
- the Donald Danforth Plant Science Center, Saint Louis, Missouri 63132, and
| | - Barbara N Kunkel
- From the Department of Biology, Washington University, Saint Louis, Missouri 63130
| | - Mark P Running
- the Department of Biology, University of Louisville, Louisville, Kentucky 40292
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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: 87] [Impact Index Per Article: 9.7] [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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45
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Cho Y, Yu CY, Iwasa T, Kanehara K. Heterotrimeric G protein subunits differentially respond to endoplasmic reticulum stress in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2015; 10:e1061162. [PMID: 26237103 PMCID: PMC4883907 DOI: 10.1080/15592324.2015.1061162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 06/06/2015] [Indexed: 05/23/2023]
Abstract
Canonical heterotrimeric G proteins in eukaryotes are major components that localize at plasma membrane and transmit extracellular stimuli into the cell. Genome of a seed plant Arabidopsis thaliana encodes at least one Gα (GPA1), one Gβ (AGB1), and 3 Gγ (AGG1, AGG2 and AGG3) subunits. The loss-of-function mutations of G protein subunit(s) cause multiple defects in development as well as biotic and abiotic stress responses. However, it remains elusive how these subunits differentially express these defects. Here, we report that Arabidopsis heterotrimeric G protein subunits differentially respond to the endoplasmic reticulum (ER) stress. An isolated homozygous mutant of AGB1, agb1-3, was more sensitive to the tunicamycin-induced ER stress compared to the wild type and the other loss-of-function mutants of G protein subunits. Moreover, ER stress responsive genes were highly expressed in the agb1-3 plant. Our results indicate that AGB1 positively contributes to ER stress tolerance in Arabidopsis.
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Affiliation(s)
- Yueh Cho
- Institute of Plant and Microbial Biology, Academia Sinica; Taipei, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica; Taipei, Taiwan
- Graduate Institute of Biotechnology and Department of Life Sciences; National Chung-Hsing University; Taichung, Taiwan
| | - Chao-Yuan Yu
- Institute of Plant and Microbial Biology, Academia Sinica; Taipei, Taiwan
| | | | - Kazue Kanehara
- Institute of Plant and Microbial Biology, Academia Sinica; Taipei, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica; Taipei, Taiwan
- Biotechnology Center, National Chung-Hsing University; Taichung, Taiwan
- Muroran Institute of Technology; Muroran, Japan
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46
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Maruta N, Trusov Y, Brenya E, Parekh U, Botella JR. Membrane-localized extra-large G proteins and Gbg of the heterotrimeric G proteins form functional complexes engaged in plant immunity in Arabidopsis. PLANT PHYSIOLOGY 2015; 167:1004-16. [PMID: 25588736 PMCID: PMC4348786 DOI: 10.1104/pp.114.255703] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In animals, heterotrimeric G proteins, comprising Ga, Gb, and Gg subunits, are molecular switches whose function tightly depends on Ga and Gbg interaction. Intriguingly, in Arabidopsis (Arabidopsis thaliana), multiple defense responses involve Gbg, but not Ga. We report here that the Gbg dimer directly partners with extra-large G proteins (XLGs) to mediate plant immunity. Arabidopsis mutants deficient in XLGs, Gb, and Gg are similarly compromised in several pathogen defense responses, including disease development and production of reactive oxygen species. Genetic analysis of double, triple, and quadruple mutants confirmed that XLGs and Gbg functionally interact in the same defense signaling pathways. In addition, mutations in XLG2 suppressed the seedling lethal and cell death phenotypes of BRASSINOSTEROID INSENSITIVE1-associated receptor kinase1-interacting receptor-like kinase1 mutants in an identical way as reported for Arabidopsis Gb-deficient mutants. Yeast (Saccharomyces cerevisiae) three-hybrid and bimolecular fluorescent complementation assays revealed that XLG2 physically interacts with all three possible Gbg dimers at the plasma membrane. Phylogenetic analysis indicated a close relationship between XLGs and plant Ga subunits, placing the divergence point at the dawn of land plant evolution. Based on these findings, we conclude that XLGs form functional complexes with Gbg dimers, although the mechanism of action of these complexes, including activation/deactivation, must be radically different form the one used by the canonical Ga subunit and are not likely to share the same receptors. Accordingly, XLGs expand the repertoire of heterotrimeric G proteins in plants and reveal a higher level of diversity in heterotrimeric G protein signaling.
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47
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Wolfenstetter S, Chakravorty D, Kula R, Urano D, Trusov Y, Sheahan MB, McCurdy DW, Assmann SM, Jones AM, Botella JR. Evidence for an unusual transmembrane configuration of AGG3, a class C Gγ subunit of Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:388-98. [PMID: 25430066 PMCID: PMC4334566 DOI: 10.1111/tpj.12732] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 11/19/2014] [Accepted: 11/21/2014] [Indexed: 05/20/2023]
Abstract
Heterotrimeric G proteins are crucial for the perception of external signals and subsequent signal transduction in animal and plant cells. In both model systems, the complex comprises one Gα, one Gβ, and one Gγ subunit. However, in addition to the canonical Gγ subunits (class A), plants also possess two unusual, plant-specific classes of Gγ subunits (classes B and C) that have not yet been found in animals. These include Gγ subunits lacking the C-terminal CaaX motif (class B), which is important for membrane anchoring of the protein; the presence of such subunits gives rise to a flexible sub-population of Gβ/γ heterodimers that are not necessarily restricted to the plasma membrane. Plants also contain class C Gγ subunits, which are twice the size of canonical Gγ subunits, with a predicted transmembrane domain and a large cysteine-rich extracellular C-terminus. However, neither the presence of the transmembrane domain nor the membrane topology have been unequivocally demonstrated. Here, we provide compelling evidence that AGG3, a class C Gγ subunit of Arabidopsis, contains a functional transmembrane domain, which is sufficient but not essential for plasma membrane localization, and that the cysteine-rich C-terminus is extracellular.
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Affiliation(s)
- Susanne Wolfenstetter
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, United States of America
| | - David Chakravorty
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane 4072, Australia
- Biology Department, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802, USA
| | - Ryan Kula
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, United States of America
| | - Daisuke Urano
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, United States of America
| | - Yuri Trusov
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane 4072, Australia
| | - Michael B. Sheahan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, 2308 Australia
| | - David W. McCurdy
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, 2308 Australia
| | - Sarah M. Assmann
- Biology Department, 208 Mueller Laboratory, Pennsylvania State University, University Park, PA 16802, USA
| | - Alan M. Jones
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, United States of America
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, United States of America
- To whom correspondence should be addressed.
| | - Jose R. Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, University of Queensland, Brisbane 4072, Australia
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48
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Xu DB, Chen M, Ma YN, Xu ZS, Li LC, Chen YF, Ma YZ. A G-protein β subunit, AGB1, negatively regulates the ABA response and drought tolerance by down-regulating AtMPK6-related pathway in Arabidopsis. PLoS One 2015; 10:e0116385. [PMID: 25635681 PMCID: PMC4312036 DOI: 10.1371/journal.pone.0116385] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 12/05/2014] [Indexed: 01/08/2023] Open
Abstract
Heterotrimeric G-proteins are versatile regulators involved in diverse cellular processes in eukaryotes. In plants, the function of G-proteins is primarily associated with ABA signaling. However, the downstream effectors and the molecular mechanisms in the ABA pathway remain largely unknown. In this study, an AGB1 mutant (agb1-2) was found to show enhanced drought tolerance, indicating that AGB1 might negatively regulate drought tolerance in Arabidopsis. Data showed that AGB1 interacted with protein kinase AtMPK6 that was previously shown to phosphorylate AtVIP1, a transcription factor responding to ABA signaling. Our study found that transcript levels of three ABA responsive genes, AtMPK6, AtVIP1 and AtMYB44 (downstream gene of AtVIP1), were significantly up-regulated in agb1-2 lines after ABA or drought treatments. Other ABA-responsive and drought-inducible genes, such as RD29A (downstream gene of AtMYB44), were also up-regulated in agb1-2 lines. Furthermore, overexpression of AtVIP1 resulted in hypersensitivity to ABA at seed germination and seedling stages, and significantly enhanced drought tolerance in transgenic plants. These results suggest that AGB1 was involved in the ABA signaling pathway and drought tolerance in Arabidopsis through down-regulating the AtMPK6, AtVIP1 and AtMYB44 cascade.
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Affiliation(s)
- Dong-bei Xu
- College of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- 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
| | - 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
| | - Ya-nan Ma
- College of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- 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
| | - 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
| | - Yao-feng Chen
- College of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
- * E-mail: (YC); (YZM)
| | - 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
- * E-mail: (YC); (YZM)
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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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50
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Abstract
Increased susceptibility to Fusarium oxysporum is one of the most conspicuous characteristics of the Arabidopsis mutants lacking the heterotrimeric G protein β and γ1 subunits. The molecular mechanisms placing these G proteins in the plant innate immunity network are yet to be discovered. However, a method to test susceptibility to and disease progression of an important plant pathogen, such as F. oxysporum, is of central importance to many plant defense studies. The optimized protocol presented here allows the routine processing and analysis of symptom progression in young Arabidopsis soil-grown seedlings and yields highly reproducible results.
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