Evolutionary history of ECA1 gametogenesis-related proteins and their roles in seed plant reproduction

分泌的富含半胱氨酸的小分子蛋白（CRPs）是调节植物营养和生殖发育多个方面的关键信号因子。植物crp的显著特征是其在开花植物（被子植物）中的进化多样化和在生殖组织中的突出表现。在被子植物雌性配子体（胚囊）中表达受限的最大的一类CRPs是ECA1（早期培养丰度1）配子体发生相关的CRPs家族。在拟南芥中，这个家族包括至少124个成员，但功能只分配给一个由5个密切相关的蛋白质组成的小亚家族，称为EC1（卵细胞1）。当两个精子从花粉管中释放到胚囊中，使精子能够与雌性配子（卵细胞和中央细胞）融合时，这些卵细胞特异性的CRPs才成为分泌细胞。本项目旨在了解陆生植物ECA1配子体发生相关crp的进化历史、功能多样性和差异表达，重点关注EC1和EC1相关亚家族的首次出现。该项目将进一步研究EC1蛋白在不同植物物种中的功能保护、EC1翻译后修饰以及氧化还原依赖机制对EC1分泌和配子融合的影响。还将对拟南芥ec1相关蛋白进行功能研究，以阐明其在生殖发育中的作用。

Secreted small cysteine-rich proteins (CRPs) are emerging as key signaling factors regulating multiple aspects of plant vegetative and reproductive development. Striking features of plant CRPs are their evolutionary diversification in flowering plants (angiosperms) and prominence in reproductive tissues. One of the largest group of CRPs with remarkably restricted expression in the female gametophyte (embryo sac) of angiosperms is the family of ECA1 (early culture abundant 1) gametogenesis-related CRPs. In Arabidopsis thaliana, this family comprises at least 124 members but a function has only assigned for a small subfamily of five closely related proteins termed EC1 (EGG CELL 1). These egg cell-specific CRPs are only secreted cell when the two sperm cells are released from the pollen tube into the embryo sac and render the sperm cells competent to fuse with the female gametes (egg cell and central cell). This project aims to contribute to the understanding of the evolutionary history, functional diversification and differential expression of ECA1 gametogenesis-related CRPs in land plants, with a special focus on the first appearance of EC1 and EC1-related subfamilies. The project will furthermore address the functional conservation of EC1 proteins among different plant species, the EC1 posttranslational modification, and the impact of redox-dependent mechanisms on EC1 secretion and gamete fusion. Functional studies will be also performed on A. thaliana EC1-related proteins to elucidate their role(s) in reproductive development.