Poster: Plant-pathogen interactions

Abs # 547: Proteome analysis of OsRac signaling in defense response of rice

Presenter:	Fujiwara, Masayuki , fujimasa@bs.aist-nara.ac.jp
Authors	Fujiwara, Masayuki  (A)   Umemura, Kenji  (B)   Kawasaki, Tsutomu  (A)   Shimamoto, Ko  (A)
Affiliations:	(A): Nara Institute of Science and Technology (NAIST) (B): Meiji Seika Kaisha Ltd.

We are studying signaling pathways in disease resistance of rice. Our previous studies indicated that OsRac 1, a small GTP-binding protein, functions as a regulator of NADPH oxidase producing reactive oxgen species (ROS) during oxidative burst. There are little information of protein expression profile in G protein mediated defense signaling. The aim of this study is to reveal the defense signaling pathway in rice by applying the proteome analysis. Proteins extracted from rice cultured cells of wild-type (WT), constitutive active OsRac 1 (CA-Rac) and dominant negative-OsRac 1 (DN-Rac) were applied to two-dimensional gel electrophoresis (2-DE). The protein separation patterns of WT, CA-Rac and DN-Rac were compared and different spots were identified. The spots were excised from 2-D gels and subjected to trypsin in-gel digestion. The peptide fragments derived from gels were identified by mass spectrometry. We also analyzed the differentially expressed proteins isolated from sphingolipid elicitor-treated cells. We detected the big different expression level of protein, in which WT, CA-Rac and DN-Rac and identified these proteins. Heat shock proteins (HSPs), G protein associated proteins, defense-related proteins and oxidative stress associated proteins were identified. Additionally, we found up- or down regulated proteins with treatment of sphingolipid elicitor. Based on this analysis, we will show the signaling pathway at the protein level in rice defense response.