Heterotrimeric G protein signalling in plant biotic and abiotic stress response

Heterotrimeric G proteins act as molecular switches to participate in transmitting various stimuli signals from outside of cells. G proteins have three subunits, Gα, Gβ, and Gγ, which function mutually to modulate many biological processes in plants, including plant growth and development, and biotic and abiotic stress responses. In plants, the number of Gγ subunits is larger than that of the α and β subunits. Based on the recent breakthroughs in studies of plant G protein signal perception, transduction and downstream effectors, this review summarizes and analyzes the connections between different subunits and the interactions of G proteins with other signaling pathways, especially in plant biotic and abiotic stress responses. Based on the current progress and unresolved questions in the field, we also suggest future research directions on G proteins in plants.