Dominant-negative mutations in small G-protein ROP6 impair stomatal closure

Abstract

Plants exchange gases with surrounding environment through stomata, specialised pores that open and close in response to various stimuli. Stomatal movements are regulated by a complex network of signalling pathways, some components of which have not been yet identified. A forward genetic screen identified an Arabidopsis line carrying mutation in small G-protein ROP6that was sensitive to ozone, had high stomatal conductance, and displayed impaired stomatal responses. In this work, we showed that the ROP6 mutation was dominant negative and caused impairment of stomatal responses to several environmental factors. By using gas exchange experiments, we also demonstrated that ROP6 acts antagonistically with another G-protein ROP2 in stomatal regulation.