Role of Heterotrimeric G-Proteins in Improving Abiotic Stress Tolerance of Crop Plants

As sessile organisms, plants are constantly exposed to a variety of environmental stresses that have detrimental effects on their growth and development, leading to major crop yield losses worldwide. To cope with adverse conditions, plants have developed several adaptive mechanisms. A thorough understanding of these mechanisms is critical to generate plants for the future. The heterotrimeric G-protein complex, composed of G alpha, G beta, and G gamma subunits, participates in the regulation of diverse cellular signaling pathways and has multiple roles in regulating plant stress responses. The complex has two functional entities, the GTP-bound G alpha subunit and the G beta gamma dimer, both of which by interacting with additional proteins can activate various signaling networks. The involvement of G-proteins has been shown in plants' response to drought, salinity, extreme temperatures, heavy metals, ozone, and UV-B radiation. Due to their versatility and the number of processes modulated by them, G-proteins have emerged as key targets for generating stress-tolerant crops. In this review, we provide an overview of the current knowledge of the roles of G-proteins in abiotic stress tolerance, with examples from the model plant Arabidopsis thaliana, where these processes are most widely studied and from additional agriculturally relevant crops, where their potential is realized for human usage.