CONICET | Buscador de Institutos y Recursos Humanos

Plants sense and interpret the light environment and adjust their growth and development accordingly. In Arabidopsis thaliana blue light is perceived by two cryptochromes (cry1 and cry2). Arabidopsis has a single gene encoding for the alpha subunit of the heterotrimeric G protein (GPA1). Heterotrimeric G proteins have been largely implicated in blue signaling during Arabidopsis seedling development. Here we combine a biochemical, molecular and genetic approach to study signaling pathway connections between GPA1 and cry1. GTP binding activity in the cry1 mutant was significantly reduced to gpa1 mutant levels. GPA transcript or protein levels were normal in the cry1 mutant and in our experimental conditions we did not find proteinprotein interaction. cry1 mutants failed in some typical gpa1 mediated responses in darkness and cry1 gpa1 double mutants studies showed genetic epistasis. Microarray experiments showed cry1 and gpa1 coregulate the expression of several genes. Finally, adult cry1 gpa1 double mutants showed altered leaf shape, trichome formation and rosette size. All these results suggest cry1 and gpa1 regulate common processes during Arabidopsis seedling development.