花粉-雌蕊相互作用的分子基础

Molecular basis of pollen-pistil interaction

显花植物授粉过程包含了花粉与雌蕊一系列复杂的细胞间相互作用.花粉在柱头上必须发生粘附与水合作用后才能萌发,花粉胞被蛋白可能在粘附机制中起主要作用,而水孔蛋白调节了花粉的水合过程;花粉管在花柱引导组织中定向生长,受引导组织胞间质、向化性物质及细胞粘附机制等因素的影响,也与花粉受体及子房有关.在植物的自交不亲和性反应中,配子体型自交不亲和性反应主要是由自交不亲和基因蛋白产物降解花粉RNA或以Ca2+介导的信号级联反应实现的;孢子体型自交不亲和性反应则依赖于干性柱头以及雌蕊的S受体激酶及S位点糖蛋白与花粉S基因配体之间的相互作用.

The process of pollination involves a series of complex cellular interactions between male and female gametes in flowering plant.Initiation of pollination is dependent on the ability of the pollen grain to adhere effectively to the stigmatic surface.Following adhesion,pollen tube growth depends on the hydration of pollen grain.Pollen coat proteins may play a major role in pollen adhesion and the aquaporin is essential for pollen hydration.Growth and guidance of pollen tube through style transmitting tissue is related to extracellular matrix of the transmitting tract,chemotrophic factors,matrix adhesiondriven,as well as pollen receptor and ovary.In selfincompatibility (SI) responses,gametophytic SI involves degradation of pollen RNA,and signaling cascade that is mediated by the activation of a calciumbased signal transduction pathway in the pollen;Sporophytic SI response depends upon the presence of a 'dry' stigmatic surface and on the interaction between pistil Sreceptor kinase,together with Slocus glycoprotein and Sgene counterpart of pollen.