在被子植物中，授粉过程依赖于种间的相互作用和雄(花粉)与雌(雌蕊)之间的信号传递，几种花粉和柱头蛋白质之间的相互作用决定了花粉的命运。
在十字花科植物中，干柱头乳头状细胞通过释放资源只给亲和的花粉来控制花粉的萌发，从而使花粉水合和萌发。尽管已经鉴定出许多促进授粉反应的柱头蛋白质，但是调节这些蛋白质功能的信号机制仍然是未知的。
在这里，我们表明，在拟南芥，一个极其功能冗余的丝裂原活化蛋白激酶(MAPK)级联是必需的，以维持柱头可授性接受相容的花粉。我们的遗传分析表明，在柱头中，5个 MAPK 激酶(mkk)、 MKK1/2/3/7/9可以将上游信号传递给2个 mpk，即 MPK3/4，从而进行亲和授粉。
在mpk4RNAi/mpk3双突变体中观察到五个mkk 在五重突变体(mkk1/2/3RNAi/mkk7/9)的授粉缺陷中的功能缺陷。
我们进一步证明这个 MAPK 连锁聚集在 Exo70A1上，Exo70A1是一个以前确定的对授粉至关重要的柱头可授性因子。
鉴于授粉是植物生殖期间至关重要的第一步，了解控制成功授粉的机制可以促进提高作物产量的策略的发展。
In angiosperms, the process of pollination relies on species-specific interaction and signaling between the male (pollen) and female (pistil) counterparts where the interplay between several pollen and stigma proteins decides the fate of the pollen. In Brassicaceae, the dry stigmatic papillary cells control pollen germination by releasing resources only to compatible pollen thereby allowing pollen to hydrate and germinate. Despite the identification of a number of stigmatic proteins that facilitate pollination responses, the signaling mechanisms that regulate functions of these proteins have remained unknown. Here we show that, in Arabidopsis, an extremely functionally redundant mitogen-activated protein kinase (MAPK) cascade is required for maintaining stigma receptivity to accept compatible pollen. Our genetic analyses demonstrate that in stigmas, five MAPK kinases (MKKs), MKK1/2/3/7/9 are required to transmit upstream signals to two MPKs, MPK3/4, to mediate compatible pollination. Compromised functions of these five MKKs in the quintuple mutant (mkk1/2/3RNAi/mkk7/9) phenocopied pollination defects observed in the mpk4RNAi/mpk3 double mutant. We further show that this MAPK nexus converges on Exo70A1, a previously identified stigma receptivity factor essential for pollination. Given that pollination is the crucial initial step during plant reproduction, understanding the mechanisms that govern successful pollination could lead to development of strategies to improve crop yield.
原文DOI：10.1016/j.molp.2020.08.015
