水稻子房特异性表达lncRNA ROVULE在胚乳发育中的功能与调控机制

The endosperm is not only the most important place for storage of nutrients in seeds, but also an important material for genetic research due to its special cellularization process. Previously, we screened an ovule-specifically expressed lncRNA, which is designated as ROVULE. Down-regulation of its expression can impede the process of endosperm cell formation, resulting in severe defects in endosperm development. We also found that ROVULE could binding to a DNA helicase family protein DHFP, indicating that they may regulate the endosperm development of rice through the formation of RNA-protein complexes. This project intends to focus on the key scientific issues of ROVULE's function and regulatory mechanism in rice endosperm development, and further perform the following research: (1) Using the gain- or loss-of-function mutation of ROVULE to analyze the function of ROVULE in endosperm development. (2) Exploring the localization and the key sites or domains of ROVULE and its interacted protein DHFP. (3) Demonstrating the molecular mechanism of ROVULE-DHFP complex in regulating rice endosperm development by using reverse genetics methods and functional complementation experiments. Approval and implementation of the project can not only reveal the new features and function of plant lncRNAs, but also can elucidate the important genes and their regulatory networks in rice seed development and provide new genetic resources for rice plants breeding.

胚乳不仅是种子内营养物质贮藏的最主要场所，还因其特殊的细胞化发育过程而成为遗传学研究的重要材料。我们前期在研究水稻生殖相关长链非编码RNA（lncRNA）时筛选到一个子房特异表达的lncRNA ROVULE，下调其表达可使胚乳细胞化过程受阻，产生严重的胚乳发育缺陷。我们还发现ROVULE可与DNA解旋酶DHFP结合，提示二者可能通过形成RNA-蛋白复合体共同调控水稻胚乳发育。本项目拟围绕ROVULE在水稻胚乳发育中的功能与调控机制这一关键科学问题，进一步开展如下研究：（1）利用ROVULE功能获得/缺失植株分析ROVULE在胚乳发育中的功能；（2）探明ROVULE及互作蛋白DHFP的定位、互作的关键位点或结构域；（3）通过反向遗传学手段和功能互补实验解析ROVULE-DHFP复合体调控水稻胚乳发育的分子机理。本项目的立项和实施可为植物种子发育研究和作物分子育种提供新的思路和遗传资源。

胚乳是水稻籽粒性状的重要组成部分，研究水稻胚乳发育的调控机理是培育高产、优质作物新品种的重要方向之一。本项目聚焦一个在雌蕊特异性表达的lncRNA ROVULE，研究其与互作蛋白DHFP共同调控水稻胚乳发育的过程与机制。按照研究计划，我们开展了基因表达分析、遗传学分析、生化与分子生物学实验等实验，发现在胚乳中ROVULE是一个母系表达的印迹基因，并且 ROVULE 在授粉后的转录水平会由于启动子区 H3K27me3 修饰的增加而降低，所以 ROVULE 授粉后的持续表达会导致胚乳发育异常。进一步研究发现 ROVULE 通过结合 DNA 螺旋酶家族蛋白 DHFP，阻止 DHFP 结合 tubulin 参与胚乳发育过程的调控，从而导致胚乳发育异常。胚乳发育机理研究不仅是植物科学领域的重大基础理论问题，也与农作物的产量与品质形成及国家粮食安全密切相关。在本项目支持下，我们已完成项目的主要研究内容，研究结果以“The parent-of-origin lncRNA MISSEN regulates rice endosperm development”为题发表在Nature Communications上。该成果可为揭示作物种子发育机理提供理论基础，同时可为作物分子遗传育种提供参考，对维护我国粮食安全方面有所助益。. 此外，申请人在此项目资助下还发现非编码RNA在调控水稻抗病性、开花和育性等方面具有重要的作用，研究结果发表在Plant Biotechnology Journal、Plant Physiology、Rice等杂志。. 总体上，在本项目支持下共发表SCI论文5篇，协助培养博士研究生1名，申请发明专利2项。