Arabidopsis ICK/KRP cyclin-dependent kinase inhibitors function to ensure the formation of one megaspore mother cell and one functional megaspore per ovule

• DOI: 10.1371/journal.pgen.1007230
• Publication Date: 2018-03-07T18:25:33Z
• Authors: Ling Cao; Sheng Wang; Prakash Venglat; Lihua Zhao; Yan Cheng; Shengjian Ye; Yuan Qin; Raju Datla; Yongming Zhou; Hong Wang
• Keywords: Megaspore; Meiocyte

In most plants, the female germline starts with differentiation of one megaspore mother cell (MMC) in each ovule that produces four megaspores through meiosis, which survives to become functional (FM). The FM further develops into an embryo sac. Little is known regarding control MMC formation per and selective survival FM. ICK/KRPs (interactor/inhibitor cyclin-dependent kinase (CDK)/Kip-related proteins) are plant CDK inhibitors cycle regulators. Here we report ovules Arabidopsis mutant all seven ICK/KRP genes inactivated, supernumerary MMCs, FMs sacs were formed two could be fertilized form embryos separate endosperm compartments. Twin seedlings observed about 2% seeds. Further, number position surviving from variable, indicating positional signal for determining was affected. Strikingly, ICK4 fusion protein yellow fluorescence strongly present degenerative but absent FM, suggesting important role ICKs degeneration non-functional megaspores. absence or much weaker phenotypes lower orders mutants complementation septuple by ICK7 indicate multiple function redundantly restricting more than critical ensure development sac ovule.