Arabidopsis PRC1 core component AtRING1 regulates stem cell-determining carpel development mainly through repression of class I KNOX genes.
BMC Biol 2016;
14:112. [PMID:
28007029 PMCID:
PMC5178098 DOI:
10.1186/s12915-016-0336-4]
[Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 11/25/2016] [Indexed: 11/27/2022] Open
Abstract
Background
Polycomb repressive complex 2 (PRC2)-catalyzed H3K27me3 marks are tightly associated with the WUS-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 in Arabidopsis thaliana. Promoter-driven GUS reporter analysis showed that AtRING1a and AtRING1b display a largely similar expression pattern, except in the case of the exclusively maternal-preferred expression of AtRING1b, but not AtRING1a, in the endosperm. Indeterminate carpel development in the atring1a;atring1b double mutant is due to replum/ovule-to-carpel conversion in association with ectopic expression of class I KNOX (KNOX-I) genes. Moreover, AtRING1a and AtRING1b 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-regulated KNOX-I pathway acts largely in a complementary manner with the WUS-AG pathway in controlling floral stem cell maintenance and proper carpel development.
Conclusions
Our study uncovers a novel mechanistic pathway through which AtRING1a and AtRING1b repress KNOX-I expression to terminate floral stem cell activities and establish carpel cell fate identities.
Electronic supplementary material
The online version of this article (doi:10.1186/s12915-016-0336-4) contains supplementary material, which is available to authorized users.
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