玉米淀粉合成相关的转录因子ZmNRP1的功能研究

The transcription factors involved in the regulation of starch synthesis in plant have been reported. However, the molecular regulation mechanism is still unclear so far. Combined with the data from RNA-seq, cis acting elements and transcription factors in rice and maize，We have successfully screened and identified a transcription factor ZmNRP1 which can directly regulate the expression of key gene in maize starch synthesis. On this basis, we will confirmed the function of transcription factor ZmNRP1 was confirmed by the by using of transgenic and screening of endosperm library and BIFC. And ChIP-seq technique was used to ananlyse ZmNRP1 regulates the target gene and bindes target site in the whole genome. These results would reveal the molecular mechanism of the molecular regulation mechanism of ZmNRP1 involved in regulation of maize starch synthesis during grain filling.

植物中转录因子参与淀粉合成关键酶基因的表达调控已陆续报道，但有关转录因子参与淀粉合成关键酶基因Bt2、Sh2、Su2和Ae的表达调控还鲜有报道且转录因子参与淀粉合成酶基因表达调控的分子机理仍不清楚。结合水稻、玉米已报道的RNA-seq、顺式作用元件和转录因子等数据进行共表达分析，本课题组前期已成功筛选并鉴定了一个能直接调控多个玉米淀粉合成关键酶基因表达的转录因子ZmNRP1。在此基础上，拟采用转基因以及筛选胚乳文库和BIFC等技术验证转录因子ZmNRP1的功能。同时，拟采用ChIP-seq技术在全基因组范围内揭示该转录因子调控的靶基因以及结合的靶位点，深入解析籽粒灌浆过程中ZmNRP1参与调控胚乳淀粉合成的分子调控机理，为开展提高玉米淀粉含量和产量的分子育种工作提供理论和技术支持。

作物籽粒灌浆是一个复杂的调控过程，主要涉及母本物质向籽粒分配和籽粒利用母本物质积累淀粉和储藏蛋白等储藏物质两个重要的生物学过程。本研究利用生化和遗传手段发现ZmNRP1和ZmNAC130通过结合顺式作用元件T/CACGCC/AA同时调控母本物质向籽粒分配的基因SWEET4C和INCW2/Mn1以及多个储藏物质积累功能基因的表达。通过构建nrp1和nac130的单双突变体，揭示这两个转录因子调控了基底胚乳传递层基因的表达，从而参与母本物质向籽粒分配的过程。此外，还揭示了这两个转录因子同时调控多个淀粉生物合成和储藏蛋白积累功能基因的表达。提出了这两个NAC类型转录因子ZmNRP1和ZmNAC130调控玉米籽粒灌浆的分子工作模型。该项目的研究结果进一步增强了人们对玉米籽粒灌浆的认识，为作物灌浆的遗传改良提供了理论基础。