Flowering time is a fundamental factor de-termining the global distribution and final yield of rice (Oryza sativa). Although diverse flowering time genes have been reported in this crop, the tran-scriptional regulation of its key flowering genes are poorly understood. Here, we report that a basic leucine zipper transcription factor, bZIP71, functions as a flowering repressor. The over-expression of bZIP71 delays flowering, while the bzip71 mutant flowers early in both long-day and short-day conditions. A genetic analysis showed that the regulation of flowering by bZIP71 might be independent of Heading date 2 (Hd2), Hd4, and Hd5. Importantly, bZIP71 directly associates with the Early heading date 1 (Ehd1) promoter and re-presses its transcription, and genetically the function of bZIP71 is impaired in the ehd1 mutant. Moreover, bZIP71 interacts with major compo-nents of polycomb repressive complex 2 (PRC2), SET domain group protein 711 (SDG711), and Fertilization independent endosperm 2 (FIE2), through which bZIP71 regulates the H3K27me3 level of Ehd1. Taken together, we present a tran-scriptional regulatory mechanism in which bZIP71 enhances the H3K27me3 level of Ehd1 and tran-scriptionally represses its expression, which not only offers a novel insight into a flowering pathway, but also provides a valuable putative target for the genetic engineering and breeding of elite rice cultivars.

Northeast Institute of Geography and Agroecology,Key Laboratory of Soybean Molecular Design Breeding,the Chinese Academy of Sciences,Harbin 150081,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Life Science,Northeast Forestry University,Harbin 150040,China;Key Laboratory of Saline-alkali Vegetation Ecology Restoration(Northeast Forestry University),Ministry of Education,Harbin 150040,China;State Key Lab of Rice Biology,China National Rice Research Institute,Hangzhou 311400,China;The Innovative Academy of Seed Design,the Chinese Academy of Sciences,Beijing 100101,China

[1]Xiufeng Li;Xiaojie Tian;Mingliang He;Xinxin Liu;Zhiyong Li;Jiaqi Tang;Enyang Mei;Min Xu;Yingxiang Liu;Zhenyu Wang;Qingjie Guan;Wei Meng;Jun Fang;Jian Zhang;Qingyun Bu-.bZIP71 delays flowering by suppressing Ehd1 expression in rice)[J].植物学报（英文版）,2022(07):1352-1363

bZIP71,termining,bzip71,Hd2,Hd4,Hd5,ehd1,SDG711,FIE2,scriptionally

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