玉米杂交种与亲本苗期叶片差异表达蛋白谱分析

Differentially Expressed Protein Profile of Maize Seedling Leaves Between Hybrid and Its Parental Lines

【目的】建立玉米杂交种与亲本苗期叶片差异表达蛋白谱,探讨叶片大小杂种优势形成的分子机理。【方法】以玉米强优势杂交种Mo17/B73及其亲本发芽后第5天的第3片叶为材料,采用双向电泳技术(2-DE),结合MALDI TOF MS质谱技术,建立叶片细胞分裂和生长关键区域的差异表达蛋白质谱,并对差异表达蛋白进行质谱鉴定。【结果】在检测到的630个蛋白质点中,有52个蛋白质点在杂交种与亲本之间的表达差异达到显著水平,表现为单亲沉默(15个)、偏高亲(13个)、偏低亲(8个)、杂种上调(6个)、杂种下调(7个)和杂种特异表达模式(3个)。另外,还成功鉴定出了其中的28个差异表达蛋白质点,涉及到代谢、胁迫响应、糖酵解、转录调控、蛋白折叠和降解、三羧酸循环、细胞骨架、发育及未知蛋白质等9个功能类别。【结论】玉米杂交种与亲本在蛋白丰度上存在明显的差异,并且差异表达蛋白涉及到多个功能类别,可能与玉米叶片大小杂种优势的形成有关。

[ Objective ] To construct protein expression profile of seedling leaves between maize hybrid and its parental lines, with the purpose to give an insight into the molecular basis of leaf size heterosis. [ Method ] Differentially expressed protein profile of the third leaf on 5th day after germination between maize hybrid and its parental lines used for 2-DE analysis and differentially expressed proteins were identified by using MALDI TOF MS method. [ Result ] A total of 630 protein spots were detected, among which 52 protein spots were found to be differentially expressed between maize hybrid and its parental lines. Differentially expressed protein spots could be grouped into six models, that is UPFI （expression in hybrid and uniparent but not in another parent）, HDH（hybrid is equal to the highly expressed parent）, LDH （hybrid is equal to the lowly expressed parent）, URH （up-regulated in hybrid）, DRH （down-regulated in hybrid）, FInBP （hybrid-specific expressed protein spots）, and the numbers were 15, 13, 8, 6, 7 and 3, respectively. Moreover, 28 of the 52 differentially expressed protein spots were identified by using MALDI TOF MS, which were grouped into nine functional categories, including metabolism, development, stress, glycolysis, transcription regulation, protein folding and degradation, tricarboxylic acid cycle, cytoskeleton and unknown protein. [ Conclusion ] Significant alterations in protein expression occurred in seedling leaves of hybrids and parental lines and differentially expressed proteins implicated in some functional categories might contribute to heterosis related to leaf size heterosis.