细胞内吞相关基因ZmEHD1调控玉米籽粒灌浆的分子机制解析

Transportation rate of photosynthate from basal endosperm transfer layer to endosperm is a key regulated factor for maize grain filling and largely determine the final grain yield. Endocytosis is one of the important transportation forms of sugar unloaded in the phloem terminal to the endosperm. ZmEHD1 controlling grain filling was cloned in a natural empty pericarp mutant and highly expressed in 15 DAP (Days after pollination) endosperm with a negative effect. This gene encodes a protein ZmEHD that is involved in endocytic trafficking. To explore the upstream and downstream genes interact with ZmEHD1, subcellular localization, RNA-Seq, yeast two-hybid system, and bimolecular fluorescence complementation system were performed. Subsequently, genes interact with ZmEHD1 were verified by real time PCR to construct the regulation network of ZmEHD1. The molecular mechanism of ZmEHD1 regulation network influencing grain filling would be further elucidated by association analysis and phylogenetic evolution analysis of the key genes in ZmEHD1 regulation network. The results will provide material and theory supports for cultivating varieties with fast grain filling and easy mechanized harvest characteristics.

光合产物经籽粒基部的胚乳转换层向胚乳转运的速率是影响玉米籽粒灌浆的关键因素，很大程度上决定了产量的形成。细胞内吞是糖分运输的一种重要形式，对卸载至韧皮部终端的光合产物向胚乳的运输有重要调控作用。本课题组前期研究克隆了一个控制籽粒灌浆的突变体基因ZmEHD1，该基因在突变体授粉后15天籽粒胚乳中高效表达，其编码的ZmEHD蛋白是细胞内吞过程的重要组分。本研究拟在前期研究的基础上，通过亚细胞定位、RNA-Seq、酵母双杂交、双分子荧光互补等分析手段，挖掘ZmEHD1基因的上下游互作基因或调控因子，并对其进行表达分析验证，解析ZmEHD1基因调控玉米籽粒灌浆过程的分子机制；结合emp7基因调控网络中关键基因的关联和进化分析，明确ZmEHD1基因调控网络影响玉米籽粒灌浆的分子代谢机制，为选育灌浆速率快、宜机械化生产的玉米新品种提供材料与理论支撑。

玉米是重要的粮饲作物，籽粒产量提高对于保障国家粮食安全和生活水平提高具有重要意义。籽粒产量来源于光合产物的积累，光合产物向胚乳转运的速率是影响玉米籽粒灌浆的关键因素，很大程度上决定了产量的形成。细胞内吞是糖分运输的一种重要形式，对卸载至韧皮部终端的光合产物向胚乳的运输有重要调控作用。本课题组前期研究克隆了一个控制籽粒灌浆的突变体基因ZmEHD1，该基因在突变体授粉后15天籽粒胚乳中高效表达，其编码的ZmEHD蛋白是细胞内吞过程的重要组分。本研究在前期研究的基础上，通过亚细胞定位、RNA-Seq、酵母双杂交、双分子荧光互补等分析手段，挖掘ZmEHD1基因的上下游互作基因或调控因子，并对其进行表达分析验证，解析ZmEHD1基因调控玉米籽粒灌浆过程的分子机制；结合emp7基因调控网络中关键基因的关联和进化分析，明确ZmEHD1基因调控网络影响玉米籽粒灌浆的分子代谢机制。研究结果可为选育灌浆速率快、宜机械化生产的玉米新品种提供材料与理论支撑。