水稻胚胎蛋白质组的深入分析揭示其在种子发芽的重要作用
利用MAPMAN分析水稻种子萌发过程中的代谢途径
水稻种子萌发是其成长为独立生命个体重要的起始点，是形成良好的幼苗的前提条件。水稻种子包含胚、胚乳等两大主要组织，在萌发过程中，胚组织的营养物质逐步分解并运输至胚中，为胚发育形成幼苗提供必要的物质和能量条件。胚组织虽然体积较小，但在萌发过程中却处于中心地位。因此，有必要对水稻胚和胚乳在萌发过程中的不同作用进行深入研究，从而深入探讨水稻种子萌发过程的分子调控机制。
中国科学院武汉植物园资源植物繁殖生物学课题组博士研究生韩超在杨平仿研究员指导下，利用基于凝胶的双向电泳技术和非凝胶的i-TRAQ技术，对水稻种子萌发过程中胚和胚乳组织分别进行蛋白质组研究。
共获得343个胚组织蛋白质在萌发过程中的表达量发生改变，包括191个下调表达和152个上调表达。这些蛋白质参与众多能量代谢途径，其中包括参与淀粉合成、支链淀粉合成的酶、淀粉粒合成酶等在萌发早期阶段上调表达而在后期阶段下调表达，该结果与实验室前期研究结果发现水稻种子萌发过程中胚组织发现淀粉粒一致。
胚组织中的蔗糖可能作为中间物为淀粉合成提供帮助。此外，通过该研究发现在水稻种子萌发过程中，胚乳组织的大量生物学过程是受胚组织调控的。
以上研究结果得到国家自然基金(31271805)、中国科学院“百人计划”和中非联合研究项目(SAJC201324)的经费支持。相关结果发表于国际期刊Plant and Cell Physiology。
原文摘要：
In-depth proteomic analysis of rice embryo reveals its important roles in seed germination
Chao Han, Dongli He, Ming Li and Pingfang Yang
Seed germination is a complex physiological process which allows the seed embryo to grow and develop into a photosynthetic organism. The two major constituents of rice seed include the embryo and endosperm with embryo being of much significance despite its small size. In this study, we conducted a systematic proteomic analysis on the embryo dissected from rice seed at different stages of germination through a combination of gel-based and gel-free strategies. Totally, 343 differentially expressed proteins were identified. Among them, 191 were decreased and 152 were increased. All these proteins could be sorted into 11 functional groups based on MapMan analysis. Some starch biosynthesis related enzymes such as starch branching enzyme, granule-bound starch synthase 1 and starch synthase increased during early stage of germination and then decreased at the late stage, which was similar with the expressional patterns of glycolysis related enzymes. However, tricarboxylic acid cycle related enzymes only increased at the late stage. It was also found that sucrose might be an important intermediate for the biosynthesis of starch in embryo. Furthermore, gel-based proteomic analysis on the dissected endosperm showed that the biological processes in endosperm were heavily regulated by the embryo. This study could provide some new insights into the distinct roles of embryo and endosperm in rice seed germination.
作者：中科院
