The Rice Small GTPase OsRac1, a Regulator of the Disease Resistance Signaling, Functions During Development of Lateral Roots and Tillers

Abstract

The OsRac1, a small GTP-binding protein, functions as a regulatory molecule for the production of reactive oxygen species (ROS) and defense response in rice. OsRac1::GFPexpression was induced by inoculation with rice blast fungus (Magnaporthe grisea), and observed in lateral root primordia, tiller buds without external induction. The DAB staining and the Evans blue staining in roots revealed that the epidermis and the cortex of parent roots and the primordia of lateral roots were stained by DAB while the basal regions of lateral roots in parent roots were stained by Evans blue. Trimeric G protein α subunit (Gα) functions upstream of OsRac1 in defense response. No difference in ROS production and OsRac1::GFPexpression between d1 mutant and wild type were detected.Gα p::Gus expression was not observed in parental root but in lateral root primordia.