拟南芥多磷酸肌醇6/3激酶基因(AtIPK2α和AtIPK2β)调控雄配子体发育和胚胎发生的研究

Inositol trisphosphate kinase plays important roles in plant development through regulating IP3 and Ca2+. In Arabidopsis, inositol trisphosphate kinase gene (also known as inositol polyphosphate 6-/3-kinase gene AtIP3K/AtIPK2) family is consist of two members, AtIPK2α and AtIPK2β. Previous studies about Arabidopsis inositol polyphosphate 6-/3-kinase genes nearly completely foucus on the functional analysis of single gene. To investigate the possibility of functional redundancy of AtIPK2α and AtIPK2β in Arabidopsis, crosses to generate double mutants were carried out. However, atipk2α;atipk2β double mutants were not recovered. Reciprocal crosses between wildtype and atipk2α/AtIPK2α;atipk2β/atipk2β (Aabb) indicated male specific transmission failure, suggesting male gametophytical lethality of the double mutant. Pollen activity analysis by Alexander staining and scanning electron microscopy (SEM) showed that pollen development was disrupted in Aabb plants. Cytological dissection using aniline blue staining revealed that pollen tube guidance of double mutant was impaired. Moreover, the impaired pollen tube guidance in Aabb plants resulted in reduced fertilization and abnormal embryo development. To gain further understanding of the regulatory mechanism of AtIPK2α and AtIPK2β in male gametophytic development and embryogenesis, screening of proteins interacting with inositol polyphosphate 6-/3-kinase was performed. A protein which previously reported to be involved in regulation of male gametophytic development and embryogenesis was isolated. Taken together, these results suggest a redundant role for AtIPK2α and AtIPK2β in male gametophytic development and embryogenesis.

三磷酸肌醇激酶通过调节IP3和Ca2+而在植物生长发育中起重要作用。拟南芥三磷酸肌醇激酶基因（又称多磷酸肌醇6/3激酶基因AtIP3K/AtIPK2）家族由两个成员AtIPK2α和 AtIPK2β组成。此前关于拟南芥多磷酸肌醇6/3激酶基因功能研究完全集中在对单个基因的分析上，AtIPK2α 和 AtIPK2β是否具有功能冗余性以及如何协同参与拟南芥生殖发育调控还完全不知道。我们最新研究发现这两个基因以功能冗余性方式调控拟南芥雄配子体发育和胚胎发生。遗传分析表明双突变致死。进一步细胞学研究发现致死是由于雄配子体发育和花粉管靶向两个过程出现异常而导致。此外借助亲和纯化和串联质谱方法，我们筛选到一个可能与AtIPK2β相互作用的重要蛋白（该蛋白之前已被报道参与雄配子体和胚胎发育调控）。我们拟通过本项目深入研究拟南芥多磷酸肌醇6/3激酶基因在雄配子体发育和胚胎发生过程中的作用及其机理。

三磷酸肌醇激酶通过调节IP3和Ca2+而在植物生长发育中起重要作用。拟南芥三磷酸肌醇激酶基因（又称多磷酸肌醇6/3激酶基因AtIP3K/AtIPK2）家族由两个成员AtIPK2α和 AtIPK2β组成。此前关于拟南芥多磷酸肌醇6/3激酶基因功能研究完全集中在对单个基因的分析上，AtIPK2α 和 AtIPK2β是否具有功能冗余性以及如何协同参与拟南芥生殖发育调控还完全不知道。我们最新研究发现这两个基因以功能冗余性方式调控拟南芥雄配子体发育和胚胎发生。遗传分析表明双突变致死。进一步细胞学研究发现致死是由于雄配子体发育和花粉管靶向两个过程出现异常而导致。此外借助亲和纯化和串联质谱方法，我们筛选到一个可能与AtIPK2β相互作用的重要蛋白（该蛋白之前已被报道参与雄配子体和胚胎发育调控）。我们拟通过本项目深入研究拟南芥多磷酸肌醇6/3激酶基因在雄配子体发育和胚胎发生过程中的作用及其机理。