ta-siRNA合成途径基因DH3调控水稻颖壳极性发育的分子机制研究

Glumes in rice not only protect the normal development of internal flower organs, but also have an important influence on the growth of brown rice. However, the current research on the molecular mechanism of the polarity development of glumes is very scarce. In this project, we identified a glume polarity developmental defect mutant dh3, which displayed narrowed or awn-like glumes. DH3 gene encodes a gene silencing suppressor 3, which is involved in the synthesis of ta-siRNA. Based on above results, the project intends to further study the function of DH3 gene by knockout and overexpression analysis, expression pattern analysis, protein localization analysis, transcriptome analysis, related gene expression analysis, cDNA library construction and interaction protein screening and identification, and small RNA sequencing analysis by means of genetics, cytology molecular biology, bioinformatics, and transcriptomics methods, to further study on the new function of DH3 gene regulating rice hull development, and deeply analyze the molecular mechanism of DH3 gene regulating the polarity development of glumes through ta-siRNA pathway. The research results have important theoretical and practical significance for comprehensive understanding of the molecular mechanism and genetic regulation network of glume polarity development and grain molecular design breeding.

水稻颖壳不仅可以保护内部花器官正常发育，还对糙米的生长具有重要影响，但目前关于颖壳极性发育的分子机制研究却十分匮乏。在本项目中，我们筛选到一个颖壳极性发育缺陷突变体dh3，颖壳退化变窄或形成芒状器官，DH3基因编码一个基因沉默抑制因子3，参与ta-siRNA的合成过程。本项目拟在此基础上，通过遗传学、细胞学、分子生物学、生物信息学、转录组学等手段，对DH3基因进行敲除和超表达分析、表达模式分析、蛋白定位分析、转录组分析、相关基因表达分析、cDNA文库构建和互作蛋白筛选与鉴定及小RNA测序分析，进一步研究DH3基因调控水稻颖壳发育的新功能，并深度解析DH3基因通过ta-siRNA合成途径调控颖壳极性发育的分子机制。研究结果对全面认识颖壳极性发育的分子机制和遗传调控网络，以及籽粒分子设计育种具有重要的理论和实践意义。

水稻颖壳不仅可以保护内部花器官正常发育，还对糙米的生长具有重要影响，因此对产量具有重要影响。在项目资助下，我们分离鉴定到一个水稻颖壳极性发育基因DH3，其突变引起颖壳等侧生器官极性发育异常，从而突变体颖壳退化变窄或变成芒状器官，进而影响籽粒形态建成和产量。DH3编码一个细胞质定位的基因沉默抑制因子3，在叶原基和小穗中强表达。DH3的突变影响小RNA含量的变化，其中，侧生器官极性发育小RNA，tasiR-ARF和miRNA165/166的表达发生显著变化。DH3的CC结构域可与OsRDR6互作，参与tasiR-ARF的合成，从而影响下游靶基因ARF2、ARF3、ARF14、ARF15的表达，调控颖壳极性发育。在项目资助下，项目主持人以第一/通迅作者在The Plant Cell、New Phytologist、Journal of Integrative Agriculture、Rice、Crop Science期刊发表论文共5篇，其中，第一资助标注论文2篇。发明专利1项。项目主持人入选重庆市英才计划青年拔尖人才，获重庆市自然科学一等奖、中国作物学会优秀博士论文奖。培养研究生2名，其中一人获国家奖学金。