SWR1-ERECTA-MIR398模块调控拟南芥珠被发育的机理研究

Integument development is directly related to ovule morphogenesis and ovule sterility. Previous studies have shown that ERECTA(ER) signaling pathway controls the development of integument and ovule morphogenesis, but the downstream function genes are not identified and the molecular mechanism of this signaling pathways in the regulation of ovule development is unclear. Chromatin remodeling complex SWR1 regulates gene transcription by changing the function of chromosome conformation. It plays key roles in the different development stages of the plants and regulates the response of plants to environment. However, whether SWR1 are implicated in the regulation of integument development and ovule morphogenesis is unknown and the regulatory mechanism is elusive. ARP6 is a subunit of SWR1 complex. Through arp6 enhancer mutant screening and molecular cloning, we found that ER mutation is responsible for the enhanced integument developmental defects in arp6 mutagenic line. Our preliminary data showed that SWR1 genetically interacted with the ER-MPK6 signaling pathway to regulate integument development and ovule morphogenesis. We have identified the downstream components MIR398C under the coordination regulation of ARP6 and ER signaling pathways. This project aimed to identify how ARP6-ER signaling pathways co-regulate the expression of MIR398C and illuminate the molecular mechanisms of integument development regulated by SWR1-ER-MIR398 module. The SWR1 chromatin remodeling complex is highly conserved among different organisms. The output of this research will shed light on the developmental mechanisms of different development systems.

珠被发育对胚珠形态建成和胚珠的育性直接相关。前人研究显示ERECTA (ER)信号通路调控珠被的发育和胚珠形态建成，但该信号通路激活的下游基因还未知、调控珠被发育的分子机制也还不清楚。SWR1具有通过改变染色体构象调控基因转录的功能，在植株不同发育阶段和植物应答环境过程中都起重要作用，但是SWR1是否参与珠被发育和胚珠形态建成还未见报道，其调控机制如何实现还不清楚。本项目前期通过SWR1成员ARP6增强子筛选和基因克隆，揭示SWR1与ER-MPK6信号通路在遗传学上互作，共同调控珠被发育和胚珠形态建成，初步鉴定SWR1与ER信号通路共同调控珠被发育的下游基因MIR398C。本项目将进一步研究SWR1与ER信号通路共同调控MIR398C的分子机理，以期揭示SWR1-ER-MIR398模块调控珠被发育的分子机制。SWR1在不同物种间高度保守，该研究成果可为不同发育系统的发育机理的解析提供借鉴。

雌配子体是植物受精的场所，但数量较少且深埋于母体组织，其发育机理是植物学研究领域的重点和难点之一。染色质重塑是基因表达调控的重要方式之一，可以在生长发育的特定时期特异性地调节关键基因的表达。染色质重塑复合物SWR1可以在染色体的特定位点把组蛋白二聚体H2A-H2B中的H2A替换为变体H2A.Z，从而改变核小体结构并激活或抑制基因的转录。但是染色质重塑复合物SWR1的功能和作用机制仍然不清楚。本项目综合利用细胞生物学、分子生物学、生物化学和遗传学的手段，研究了染色质重塑复合物SWR1与ER-MPK信号途径相互作用共同调控胚囊和珠被的发育。我们进一步发现，染色质重塑复合物SWR1与ER信号途径通过抑制MIR398基因的转录调控拟南芥雌配子体和珠被的同步生长和发育。本研究系统阐明了SWR1与ER信号通路共同调控的下游基因MIR398C，建立信号调控网络，为解答染色质重塑复合物SWR1调控珠被发育的分子机制等关键科学问题，提供了重要的参考和理论依据。本项目原目标，全部完成。本项目共发表 SCI 收录论文6篇，其中第二标注 SCI论文2篇，Tropical Plant Biology，第三标注SCI论文3篇，包括 New Phytologist 2篇，BMC Genomics 1 篇，第四标注SCI论文1篇，Plant Journal。

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