玉米籽粒发育早期,代谢活动旺盛,细胞分裂与增大活跃,为后续贮藏物质的合成形成充足库容.为阐明籽粒早期发育的蛋白合成、积累与调控过程,本研究以夏玉米品种登海661为试验材料,在开花期人工饱和授粉后第3、第5、第10天取果穗中部籽粒,利用同位素标记相对定量(iTRAQ)技术分析其蛋白差异表达特性.玉米籽粒早期发育阶段总计鉴定及定量2639种蛋白,这些蛋白涉及多种生物过程与分子功能,其中代谢过程和分子过程是最主要的2个生物过程;催化活性和绑定功能是最主要的2个分子功能,这些生物过程与分子功能对籽粒早期发育具有重要作用.定量分析结果表明137种蛋白在籽粒发育早期显著差异表达,其功能涉及蛋白代谢、胁迫响应、细胞生长与分裂、碳水化合物与能量代谢、转运、次生物质代谢、淀粉合成、转录、油脂代谢、信号转导、氨基酸代谢等.其中,表达差异较大的是与蛋白代谢、胁迫响应、细胞生长与分裂以及碳水化合物与能量代谢相关的蛋白.表达模式聚类结果显示这些不同功能类别的蛋白协同表达,共同调控玉米籽粒的早期发育.%During the early stage of maize grain development, the metabolic activity is strong and the cell division and enlarge-ment processes are also active, leading to increase the grain sink size for subsequent accumulation of storage material. To explore the protein synthesis, accumulation and regulation during early maize grain development, grains of maize cultivar Denghai 661 in the middle of ear were harvested at 3, 5, and 10 days after flowering artificial saturation pollination, respectively, and analyzed by isobaric tags for relative and absolute quantitation (iTRAQ) proteomics. A total of 2639 proteins were identified and quantified in maize grain during early stages of development, showing that these proteins were involved in diverse biological processes and molecular functions, of which the metabolic process and molecular processes were the two most important biological processes, and the catalytic activity and binding were the two most important molecular functions, all of them played important roles in maize grain development. Quantitative analysis showed that 137 proteins significantly differentially expressed during early maize grain development, and these proteins were involved in protein metabolism, stress response, cell growth and division, carbohy- drate and energy metabolism, transport, secondary metabolism, starch synthesis, transcription, lipid metabolism, signal transduc-tion and amino acid metabolism. Among them, the proteins expressed more differentially were related to protein metabolism, stress response, cell growth and division, carbohydrate and energy metabolism. Expression patterns clustering analysis showed that these proteins in different functional categories expressed synergically to regulate the early development of maize grain.
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