玉米PLATZ基因家族参与胚乳发育及储藏物质合成的分子机理

玉米fl3突变体是胚乳灌浆缺陷的经典突变体，编码PLATZ蛋白，通过与RNA聚合酶III转录复合体互作，调控5SrRNA和tRNA的转录（Plant Cell，2017）。申请人前期的工作虽然已经克隆了这个基因，但Fl3和PLATZ家族的遗传调控网络和分子机理还有待进一步研究。本项目拟利用CRISPR技术创建4个玉米胚乳高表达的PLATZ家族突变体及突变组合，同时采用EMS技术创建FL3蛋白结构域功能缺失突变体，从正向和反向遗传学角度开展系统的网络解析工作。联合利用RNA-seq和ChIP-seq技术，全基因组扫描分析FL3下游基因，探索FL3转录调控的分子机理。最终阐明FL3及PLATZ在玉米胚乳发育和储藏物质合成中的生物学功能和分子机理，为玉米品质改良提供理论支撑。

The maize floury3 (fl3) mutant encodes a PLATZ family protein, which regulates the transcription of 5S rRNA and tRNA through interacting with RNA polymerase III transcription complex, and then influences the synthesis of corn endosperm storage reserves (Plant Cell，2017). Although the applicants have cloned fl3, the biology function of FL3 is still unknown. In this project, we’ll create null mutants of four PLATZ members by CRISPR/Cas9, which are highly expressed in the developing maize seed and potentially have functional redundancy. Meanwhile, we will apply EMS technology to create different fl3 allelic mutants. So, we apply the forward and reverse genetic technology to investigate the molecular biological function and mechanism of FL3 and PLATZ family. We then aim to dissect the downstream network of FL3 and explore the molecular mechanism of this protein though RNA-seq and ChIP-seq analysis. In summary, the goals of the current project are to reveal the molecular mechanism of the four PLATZ members including Fl3 and their roles in the maize endosperm development and the synthesis of storage reserves. The outcome of this project is expected to provide new candidate genes and mechanisms for genetic improvement in maize nutritional quality and yield.