拟南芥珠被发育的信号网络与调控机理

Ovule is the female reproductive organ of angiosperms, in which the female gametophyte-embryo sac- develops for double fertilization to produce seeds. Receptor kinases locate on cell surface to perceive signals from environment and transduce signals into cell to regulate cell growth, development and differentiation. The somatic embryogenesis receptor-like kinase (SERK) family consists of five members of leucine-rich repeat receptor-like kinase. SERKs play crucial roles in brassinosteroid signal transduction, male sporogenesis, plant innate immunity. Our preliminary studies indicated that loss-of-function of these SERKs resulted in defective ovule development, i.e., the integuments stop developing after their initiation in a SERK triple mutant, suggesting that they also play essential roles in Arabidopsis ovule development. Yeast two hybrid experiments indicated that SERKs can interact with ER that regulates integument development in Arabidopsis. Based on the preliminary results, the current project proposes to study the signal transduction pathways regulated by SERKs during integument development. Interaction proteins of SERKs in ovule and new genes functioning together with SERKs to regulate integument development will be screened and characterized. The studies will further reveal the molecular mechanisms regulated by SERKs in Arabidopsis integument development. A final molecular model for integument development will be established accordingly.

胚珠是被子植物的雌性生殖器官，其中孕育着雌配子体──胚囊，胚珠的正常发育是植物产生种子的关键。细胞表面的受体激酶接受周围环境的信号，并将信号传递到胞内，调控细胞的生长、发育和分化。拟南芥中的5 个富含亮氨酸重复受体激酶组成SERK 亚家族，它们在油菜素内酯信号转导、雄配子体发生、植物先天免疫等重要生物学过程中有着非常重要的作用。申请人的前期工作已经证明这些SERK基因也调控拟南芥的胚珠发育，SERKs 的缺失导致内外珠被发育起始后停滞，在酵母系统中SERKs 能和调控胚珠珠被发育的ER 蛋白家族相互作用。本项目旨在已有的工作基础上，研究拟南芥胚珠珠被发育过程中可能受到SERKs 调控的信号转导途径，寻找在拟南芥珠被发育过程中与SERKs 相互作用的蛋白质，筛选与SERKs 一起调控珠被发育的新基因，建立珠被发育的分子调控模型，从而揭示SERKs 调控拟南芥珠被发育的分子机理。

胚珠是被子植物的雌性生殖器官，其中孕育着雌配子体──胚囊，胚珠的正常发育是植物产生种子的关键。细胞表面的受体激酶接受周围环境的信号，并将信号传递到胞内，调控细胞的生长、发育和分化。拟南芥中的5个富含亮氨酸重复受体激酶组成 SERK亚家族，它们在油菜素内酯信号转导、雄配子体发生、植物先天免疫等重要生物学过程中有着非常重要的作用。我们通过反向遗传学研究证明这些SERK基因也调控拟南芥的胚珠发育，SERKs的缺失导致内外珠被发育起始后停滞；SERKs能和调控胚珠珠被发育的ER受体激酶蛋白家族相互作用；持续性激活的YODA和MKK3能够部分回复突变体的胚珠发育缺陷；在野生型材料中过表达EPFL家族成员能够重现serk突变体的胚珠发育缺陷表型。我们的研究结果证明SERKs和ER形成受体复合物，感知EPFL多肽信号，通过MAPK信号途径调节胚珠的发育。