Small GTPase OsRac1-indued S-nitrosylation of GAPDH is invovled in disease resistance to rice blast fungus
Y. KAWANO (1), K. Kosami (1), J. Su (2), K. Shimamoto (2) (1) Shanghai Center for Plant Stress Biology, China; (2) Nara Institute of Science and Technology, Japan

Nitric oxide (NO) has been known as an important messenger in plant defense signaling. NO directly controls the activity and/or subcellular localization of proteins thorough S-nitrosylation at sulfhydryl residues of proteins. We have previously found that OsRac1 act as one of the major regulators in rice immunity. However, it remains largely unknown how NO regulates defense resistance in plants. Here, we found that the expression of constitutively active OsRac1 enhanced NO production, on the other hand, the chitin-induced NO production was inhibited in OsRac1 RNAi cells, indicating that OsRac1 acts as a positive regulator of NO production. Furthermore, we identified glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a novel component of the OsRac1 complex. S-nitrosylation of GAPDH at Cys154 was detected by the treatment of NO donor, GSNO, in vitro. Plants expressing GAPDH C154S which lack the S-nitrosylation residue lowered the disease resistant to rice blast fungus when compared to plants expressing GAPDH WT. Taken together, these results suggest that OsRac1 acts as a key regulator of NO production and OsRac1-induced S-nitrosylation of GAPDH plays a critical role for disease resistance to rice blast fungus.

Abstract Number: P17-544
Session Type: Poster