Abstract: 【Objective】The objective of this study is to screen, identify and analyze the differentially expressed proteins in rice seedlings after infection with Rice grassy stunt virus (RGSV), and to shed new lights on the understanding of molecular mechanisms of RGSV pathogenesis.【Method】Two-dimensional fluorescence difference in gel electrophoresis (2D-DIGE) coupled with matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS) was used to analyze and identify differentially expressed protein spots. BioTools was used to search the matched proteins in NCBI database. Bioinformatics included GO (Gene ontology) terms and KEGG (Kyoto encyclopedia of genes and genomes) pathway analysis.【Result】The proteomic profile of the leaves of rice cultivar Xianyou 63 infected with RGSV compared with the control healthy plants was explored by 2D-DIGE. One-hundred and seventy-three protein spots (differential ratio＞1.5) were differentially expressed by RGSV infection over the healthy rice plants, including 72 up-regulated and 101 down-regulated protein spots. Among them, 25 differentially expressed protein spots were identified, including RuBisCO large subunit, sedoheptulose-1,7-bisphosphatase precursor, putative tyrosine phosphatase, HAD-superfamily hydrolase, subfamily IA, variant 3 containing protein, chain S, crystal structure of activated rice Rubisco complexed with 2-carboxyarabinitol-1,5-bisphosphate, C1-like domain containing protein, 20.6 K nonstructural protein (RGSV), P5 protein (RGSV) and some hypothetical proteins. GO function analysis revealed that the proteins’ biological processes were mainly involved in biological process, metabolic process, single-organism metabolic process, nitrogen compound metabolic process, nitrogen cycle metabolic process and nitrogen fixation, and the proteins’ molecular functions included molecular function, catalytic activity, ligase activity, ligase activity-forming carbon-nitrogen bonds, acid-ammonia ligase activity, ammonia ligase activity and glutamate-ammonia ligase activity. The proteins located different cell parts including cell, cell part, cellular component, cytoplasm, cytoplasmic membrane-bounded vesicle, cytoplasmic part, cytoplasmic vesicle, intracellular, intracellular membrane- bounded organelle, intracellular organelle, intracellular part, membrane, membrane-bounded organelle, membrane-bounded vesicle, mitochondrion, organelle, plastid and vesicle. KEGG pathway analysis suggested that the metabolic pathways of these proteins were those of metabolic pathways, carbon fixation in photosynthetic organisms, carbon metabolism, glyoxylate and dicarboxylate metabolism, alanine, aspartate and glutamate metabolism, biosynthesis of amino acids, pyruvate metabolism, arginine and proline metabolism, glutathione metabolism and nitrogen metabolism.【Conclusion】According to the proteomic profile of rice seedling infected with RGSV, 24 proteins identified might be related to the pathogenicity of RGSV which provided an insight into the interactive relationship between RGSV and the host rice. The biological process and photosynthesis process related to nitrogen changed more obviously.

Key words: Rice grassy stunt virus , differentially expressed proteins , 2D-DIGE , MALDI-TOF-MS