Arabidopsis PRC1 core component AtRING1 regulates stem cell-determining carpel development mainly through repression of class I KNOX genes. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Chen, Donghong; Molitor, Anne; Xu, Lin; Shen, Wen-Hui
• Is Part Of: BMC biology. Volume 14:Issue 1(2016)
• Page Start: 1
• Page End: 17
• Publication Date: 2016-12
• Subjects: Polycomb -- AtRING1 -- KNOX-I -- Floral stem cell -- Carpel development; Biology -- Periodicals; Medical sciences -- Periodicals; Biomedical Research -- Periodicals; 570.5
• DOI: 10.1186/s12915-016-0336-4
• Languages: English
• ISSNs: 1741-7007

Abstract

Abstract Background Polycomb repressive complex 2 (PRC2)-catalyzed H3K27me3 marks are tightly associated with theWUS -AG negative feedback loop to terminate floral stem cell fate to promote carpel development, but the roles of Polycomb repressive complex 1 (PRC1) in this event remain largely uncharacterized. Results Here we show conspicuous variability in the morphology and number of carpels among individual flowers in the absence of the PRC1 core components AtRING1a and AtRING1b, which contrasts with the wild-type floral meristem consumed by uniform carpel production inArabidopsis thaliana . Promoter-driven GUS reporter analysis showed thatAtRING1a andAtRING1b display a largely similar expression pattern, except in the case of the exclusively maternal-preferred expression ofAtRING1b, but notAtRING1a, in the endosperm. Indeterminate carpel development in theatring1a;atring1b double mutant is due to replum/ovule-to-carpel conversion in association with ectopic expression of class IKNOX (KNOX-I ) genes. Moreover, AtRING1a andAtRING1b also play a critical role in ovule development, mainly through promoting the degeneration of non-functional megaspores and proper integument formation. Genetic interaction analysis indicates that the AtRING1a/b-regulatedKNOX-I pathway acts largely in a complementary manner with theWUS-AG pathway in controlling floral stem cell maintenance and proper carpel development. Conclusions Our study uncovers a novel mechanistic pathway through whichAtRING1a andAtRING1b repressKNOX-I expression to terminate floral stem cell activities and establish carpel cell fate identities.