G-protein α-subunit (GPA1) regulates stress, nitrate and phosphate response, flavonoid biosynthesis, fruit/seed development and substantially shares GCR1 regulation in A. thaliana.
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.
University School of Biotechnology, G.G.S. Indraprastha University, Sector 16 C, Dwarka, New Delhi, 110078, India.
Navjyoti
N
Chakraborty
University School of Biotechnology, G.G.S. Indraprastha University, Sector 16 C, Dwarka, New Delhi, 110078, India.
Priyanka
P
Sharma
Department of Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
Kostya
K
Kanyuka
University School of Biotechnology, G.G.S. Indraprastha University, Sector 16 C, Dwarka, New Delhi, 110078, India.
Ravi Ramesh
RR
Pathak
School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.
Devapriya
D
Choudhury
Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
Richard
R
Hooley
University School of Biotechnology, G.G.S. Indraprastha University, Sector 16 C, Dwarka, New Delhi, 110078, India. raghuram98@hotmail.com.
Nandula
N
Raghuram
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D005419:Flavonoids / Q000096:biosynthesis; D005638:Fruit / Q000254:growth & development / Q000378:metabolism; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D017343:Genes, Plant; D009154:Mutation; D009566:Nitrates / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D030821:Plants, Genetically Modified; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological
D029681:Arabidopsis Proteins; D005419:Flavonoids; C112029:GCR1 protein, Arabidopsis; C429765:GPA1 protein, Arabidopsis; D044385:GTP-Binding Protein alpha Subunits; D009566:Nitrates; D010710:Phosphates; D043562:Receptors, G-Protein-Coupled
Arabidopsis thaliana; Development; Flavonoid; Functional genomics; G-protein; GCR1; GPA1; GPCR; Gα; Microarray; Nutrient; Stress; Transcriptome