Stigma Receptivity Is Controlled by Functionally Redundant MAPK Pathway Components in Arabidopsis

• 作者: Muhammad Jamshed Subramanian Sankaranarayanan Kumar Abhinandan Marcus A. Samuel
• 来源期刊: 分子植物（英文版）
• 年，卷（期）: 2020,（11）
• 所属期刊栏目: Research Articles
• 页码范围: 1582-1593
• 页数: 12页
• 语种: 英文

摘要

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 pro-teins decides the fate of the pollen.In Brassicaceae,the dry stigmatic papillary cells control pollen germi-nation 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 mpk4RNAilmpk3 double mutant.We further show that this MAPK nexus converges on Exo70A1,a previ-ously 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.