To discover crucial proteins related to wheat male sterility,we performed intact chloroplast isolation and protein extraction from wheat floret are required.Wheat floret cells from a male sterile line induced by chemical hybridizing agent SQ-1 were broken with a mechanistic blender and filtered through four muslin-layers.The protein components of the floret chloroplast were purified by sucrose density gradient differential centrifugation.Two-dimensional electrophoresis with immobilized pH(4 ～ 7) gradients as the first dimension and 13% SDS-PAGE as a second dimension was conducted with the obtained proteins.The silver-stained protein spots were analyzed with PDQuest software,about 150 protein spots were detected reproducibly within pI 4 ～ 7,17 spots were found to be differentially expressed,6 of which were subjected to MALDI-TOF-MS analysis and identified as PAP-fibrillin,ATRABB1A,pleckstrin homology(PH) domain-containing protein /Rho GAP domain-containing protein,R2R3-MYB transcriptional regulator and a hypothetical protein.These identified proteins were preferentially involved in hormone modulation,translocation of protein,protein-protein interaction,active oxygen accumulation and anther development.It suggested that the male sterility induced by SQ-1 might be directly related to the alternation of these physiological metabolisms in wheat.