玉米C型细胞质雄性不育系C48-2及其保持系线粒体差异蛋白分析

采用固相pH梯度-SDS PAGE双向电泳, 对玉米C型细胞质雄性不育系(C48-2)及其保持系(N48-2)单核期花药线粒体蛋白质进行了分离, 经考马斯亮蓝染色, 得到重复性较好的双向电泳图谱。PDQUEST软件可识别约260个蛋白质点, 对其中10个重复性比较好且差异表达在2倍以上的蛋白质点, 采用基质辅助激光解析分离飞行时间质谱进行肽指纹图谱分析, 然后用Mascot软件对NCBI数据库搜索, 其中2个蛋白质点被鉴定为谷氨酸脱氢酶(GDH)和依赖电压阴离子通道蛋白-1(VDAC1)。GDH的高表达会影响正常的氮代谢, 导致细胞的能量供应发生障碍, 有可能导致雄性不育; VDAC1是线粒体外膜上控制细胞通透性的蛋白, 与植物的程序性死亡密切相关。

Analysis of Differential Expression of Mitochondrial Proteins between C-Type Cytoplasmic Male Sterility Line C48-2 and Maintainer in Maize

Cytoplasmic male sterility (CMS) in maize (Zea mays L.) is categorized into T-CMS, C-CMS, and S-CMS types based on the specific restoration of nuclear gene, in which C-CMS has a great application potential in maize hybrid breeding due to its stable sterility and resistance to Helminthosporium maydis Nisik. The sterile mechanism of C-CMS is not fully understood for its later discovery and utilization than these of T-CMS and S-CMS. The objective of the study was to give some evidences and explanations to the sterility reason of C-CMS in maize by analyzing the differential expression of anther mitochondrial proteome between a C-type sterile line (C48-2) and its maintainer (N48-2). The mitochondrial proteins in anthers of C48-2 and N48-2 were separated firstly by two-dimensional electrophoresis with immobilized pI (3-10, non-linear) gradients and then by SDS-PAGE. The coomassie brilliant blue-stained protein spots were analyzed using PDQUEST software, there were about 260 detectable spots on each 2D-gel. With direct MALDI-TOF mass spectrometry analysis and protein database searching, only 2 out of 10 protein spots were identified with significative data, which were up-regulated in mononuclear phase of C48-2. They were identified as glutamate dehydrogenase (GDH) and voltage-dependent anion channel protein-1 (VDAC1), respectively. The GDH exists mainly in mitochondria of higher plants and plays an important role in nitrogen metabolism. Once the GDH is up-regulated at any phase of plant development, the normal supply of energy will be affected, probably leading to cytoplasmic sterility. The VDAC1 plays an essential role not only in the permeability of the mitochondrial membrane, but also in apoptosis mediated by the mitochondrial pathway. Overexpression of VDAC1 in a variety of cells induced apoptotic cell death, indicating VDAC1 as a conserved mitochondrial element of the death machinery. Our research suggests that the GDH and VDAC1 in mitochondria probably cause the sterility in C-CMS in maize.