大麦“开-闭”颖过程中浆片“膨胀-收缩”的细胞渗透调节机制

Artificial regulation of floret opening and closing is an important attempt to control anthesis, which in turn to obtain the synchronization of anthesis between parents in hybrid seed production and to avoid the pollen-mediated transgene flow. Lodicules are the two diminutive organs lying between the lemma and the ovary basis in the grass floret. At anthesis of cereal crops, rapid swelling and subsequent wilting of the lodicules plays a crucial role in mediating floret opening and closing. To elucidate the mechanism of floret opening and closing, the morphology and development of the lodicules have been the subject of a great deal of previous researches, yet much remains to be learned concerning the actual events occurring in lodicule cells during its swelling and wilting, like how the action “swelling – wilting” is activated and regulated? etc. In this project, the lodicule cells obtained from the novel wild barleys from Tibet and Israel “Evolution Canyon” and modern cultivated barleys by laser capture microdissection will be investigated by “Omics” techniques coupled with microelectrode ion flux estimation, in attempt to reveal (1) what kind of osmoticums mediate the swelling and wilting of lodicule?; (2) How do these osmoticums accumulate in the cells, and which genes work on it?. The results obtained in this research will be helpful for understanding the genetic diversity of barley germplasm resources, bring forward new insights into the mechanism of floret opening and its signal regulatory networks, and providing the noval “targets” and theories for utilization of heterosis in barley breeding.

人工调控颖花开闭对指导作物的杂交育种和制种进而促进杂种优质利用具有重要意义。已知禾本科植物花器中的浆片膨胀与收缩在颖花开放与关闭过程中起着关键性作用，其形态结构和器官建成在颖花开闭特性上的功能虽已基本明确，但有关开闭颖过程中浆片的“膨胀–收缩运动”是如何启动、进行并被调控的问题，迄今仍鲜有研究。本项目以西藏野生大麦、以色列“进化峡谷”野生大麦以及栽培大麦为试验材料，利用激光捕获显微切割技术“靶向”浆片可膨胀细胞，结合“组学”、全基因组测序以及电生理学等先进技术，旨在解析以下两个问题：（1）大麦开闭颖过程中介导浆片膨胀与收缩的渗透物质是什么？（2）浆片“膨胀–收缩”过程中，渗透物质是如何在浆片膨胀细胞中快速积累的？哪些基因或蛋白在起主要作用？本项目可望深入阐明颖花的开闭机理及其信号调控网络，研究结果对于推进大麦的杂种优势利用和品种改良实践具有重要的理论指导意义。

人工调控颖花开闭对指导作物的杂交育种和制种进而促进杂种优质利用具有重要意义。已知禾本科植物花器中的浆片膨胀与收缩在颖花开放与关闭过程中起着关键性作用，其形态结构和器官建成在颖花开闭特性上的功能虽已基本明确，但有关开闭颖过程中浆片的“膨胀–收缩运动”是如何启动、进行并被调控的问题，迄今仍鲜有研究。本项目以开颖大麦栽培品种沪1154为试验材料，首先通过对开闭颖不同时期浆片器官形态和细胞结构的显微观察，明确了开闭颖过程中浆片形态变化的主要节点及其主要功能细胞群。随后，在大麦开闭颖关键时间节点，以浆片维管束周围的膨胀薄壁细胞作为深入研究浆片活动的靶标区域，对其进行了mRNA、miRNA、lncRNAs、circRNA、代谢组等多组学分析，不仅鉴定到诸多参与浆片膨胀-收缩活动的基因，其功能包括跨膜转运、物质代谢、细胞骨架变化以及蛋白激酶等；而且发现参与浆片膨胀-收缩活动的代谢物主要为氨基酸等小分子化合物以及茉莉酸等内源激素类化合物，初步明确了大麦颖花开闭过程中浆片膨胀-收缩活动的动力来源为细胞内内含物的变化以及细胞骨架结构的变化。同时，本项目首次将上述浆片的组学测序结果进行联合分析，发现了影响浆片膨胀-收缩的lncRNAs-miRNA-mRNA互作调控网络，为进一步挖掘关键Hub基因，深入解析浆片膨胀-收缩活动的生理与分子机制奠定了基础。