低温胁迫下白菜型冬油菜差异蛋白质组学及光合特性分析

分离鉴定白菜型冬油菜低温差异表达蛋白质, 从蛋白质组角度揭示白菜型冬油菜抗寒机理奠定基础。以强抗寒白菜型冬油菜陇油7号为材料, 采用双向电泳和质谱分析技术, 比较低温(4°C、–4°C)和常温(25°C/20°C)下叶片蛋白质组差异；对差异蛋白进行KO和KEGG功能分析。结果表明，低温下陇油7号生长点下陷、植株匍匐, 气孔处于关闭或半关闭状态。2-DE和PDQuest8.0.1软件分析表明, 常温和4°C低温下叶片蛋白质斑点数分别726、738；相对于常温处理, 4°C低温下陇油7号叶片10个蛋白点特异表达、5个蛋白点未表达；MALDI-TOF-TOF MS质谱分析鉴定出11个蛋白质, 参与碳水化合物代谢、糖代谢、氨基酸代谢、有机酸代谢、核酸代谢、信号转导与细胞通讯等细胞过程。冰晶形态显微观察结果表明低温处理后陇油7号叶片蛋白质提取液中含有高活性抗冻蛋白(antifreeze proteins, AFPs)。鉴定的11个蛋白质中, 有5个蛋白质点与光合作用有关, 低温下陇油7号叶片1,5-二磷酸核酮糖羧化酶(RuBPCase)活性和净光合速率Pn下降。叶片Pn下降与RuBPCase表达抑制和活性降低有关, 非气孔限制是Pn下降的主要因素；高活性抗冻蛋白在白菜型冬油菜抗寒中发挥重要作用。

Differential Proteomic Analysis and Photosynthetic Characteristics of Winter Rapeseed under Low Temperature Stress

Isolation and identification of the differentially expressed proteins in winter rapeseed at low temperature, laid a foundation for revealing the mechanism of cold resistance of winter rapa. The strong cold resistant winter rape Longyou 7 was used as experimental material. Two dimensional electrophoresis, mass spectrometry and retrieval techniques were used to compare the proteomic differences at low temperature (4°C, –4°C) and normal atmospheric temperature (25°C/20°C), and functions were analyzed by KO and KEGG. It was observed that Longyou 7 had subsided growth point, creeping stem, and closed or semi closed stomata under low temperature. The 2-DE and PDQuest8.0.1 software analysis showed that the number of protein spots were 726 and 738, respectively. Compared with the normal temperature treatment, at the 4°C treatment showed differential expression at 10 protein spots while didn''t at five protein. Eleven proteins were identified by MS MALDI-TOF-TOF mass spectrometry analysis. They are involved in carbohydrate metabolism, rugan metabolism, amino acid metabolism, organic acid metabolism, nucleic acid metabolism, signal transduction in cell and communication and other cellular processes. we found the high activity of antifreeze protein in Longyou 7 leaf protein extraction solution after low temperature treatment through ice crystal morphology microscopic observation. Five out of the 11 proteins identified were associated with photosynthesis. Under low temperature, ribulose 1,5-bisphosphate carboxylase (RuBPCase) activity and photosynthetic rate decreased in leaved of Longyou 7. Under the low temperature, the proteome of winter rape was significantly changed, and the specific protein was expressed. The decrease of Pn in leaves was related to the expression inhibition and the activity decrease of RuBPCase. The decrease of Pn in leaves was mainly caused by non stomatal limitation. High activity of antifreeze protein plays an important role in cold resistance of winter rape.