Isolation, in silico characterization, localization and expression analysis of abiotic stress-responsive rice G-protein β subunit (RGB1)

Abstract

Heterotrimeric G-proteins constitute the classical signaling paradigm along with their cognate G-protein coupled receptors (GPCRs) and appropriate downstream effectors. G-protein complex is composed of highly conserved Gα, Gβ, and Gγ subunits. In the present study, we have characterized the cis-regulatory elements of the promoter, signature motifs, transcript profile in response to abiotic stresses, and sub-cellular localization of G-protein β subunit RGB1(I) from Indica rice. The RGB1(I) promoter sequence has various stress-related cis-regulatory elements suggesting its role in abiotic stress signaling. Presence of six WD-40 repeat signature motifs in RGB1(I) suggest its role in exchange of GDP by GTP in Gα subunit and receptor recognition. Presence of multiple N-myristoylation consensus sites in RGB1(I) protein sequence, which is necessary for membrane localization of protein, confirms the association of RGB1(I) in plasma membrane. Extrinsic association of RGB1(I) with plasma membrane seems essential for its role in regulation of signaling pathways and adaptation to high salt stress. We report the sub-cellular localization of RGB1(I) in plasma membrane, cytosol and nucleus. The localization of RGB1(I) in nucleus supports its possible interaction with transcription factors regulating the expression of salt stress responsive genes. The RGB1(I) transcript was upregulated under KCl, cold, dehydration and micronutrient (Mn²⁺ and Zn²⁺) stress. However, transcript variation under elevated temperature, ABA, NaCl, and toxic heavy metals (viz. arsenite, arsenate, cadmium and lead) was not encouraging. These evidences indicate an active and significant role of RGB1(I) in the regulation of abiotic stresses in rice and propound its possible exploitation in the development of abiotic stress tolerance in crops.

Keywords: :

• Abiotic stress
• heterotrimeric G-proteins
• metals
• rice G-protein beta-subunits
• signal transduction, sub-cellular localization

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

Work on plant abiotic stress tolerance and G-protein signaling in NT’s laboratory is supported by Department of Biotechnology (DBT), and Department of Science and Technology (DST), Government of India. We thank to Mrs. Poornima for technical help in confocal microscopy. We thank Dr. Renu Tuteja and Mr. Deepak Bhardwaj for their help in corrections of the manuscript.

Author Contributions

DKY performed the research, analyzed data, and wrote the manuscript; DS performed the experiments and helped in writing the manuscript; NT designed research, analyzed the data, and wrote the manuscript.