Li Xiufeng, Zhu Jiaping, Tian Xiaojie, Liu Yingxiang, Wei Jiaming, Hong Zhipeng, Jin Xin, Chen Chunxiao, Wang Zhenyu, Tang Jiaqi, Song Xianwei, Bu Qingyun
State Key Laboratory of Black Soils Conservation and Utilization, Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, China.
Laboratory of Advanced Breeding Technologies, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
Plant Biotechnol J. 2025 Sep;23(9):3824-3837. doi: 10.1111/pbi.70206. Epub 2025 Jun 15.
Heading date is a crucial agronomic trait that determines the adaptability of rice to specific planting regions and seasons. Although numerous heading date genes have been well characterized in rice, epigenetic regulation of flowering time remains limited. In this study, we identified JmjC (Jumonji C) domain-containing gene JMJ720 as a novel heading date-regulated gene. Mutation of JMJ720 leads to early flowering in both LD (long-day) and SD (short-day) conditions. The JMJ720 protein specifically functions as histone H3 lysine 9 demethylase (H3K9me2) in vitro and in vivo. Furthermore, we identified POH1 as an interacting protein of JMJ720, which recruits JMJ720 to regulate the histone methylation levels of Hd1, thereby negatively regulating rice flowering. Three JMJ720 haplotypes (Hap1, Hap2 and Hap3) were found in the world rice collection. Hap1 and Hap2 were predominant in indica and japonica, respectively, and both haplotypes showed a widespread distribution across China. Collectively, this study reveals the molecular network of epigenetic modifications involved in heading date regulation and provides new target genes for molecular breeding in rice.
抽穗期是决定水稻对特定种植区域和季节适应性的关键农艺性状。尽管水稻中众多抽穗期基因已得到充分表征，但开花时间的表观遗传调控仍很有限。在本研究中，我们鉴定出含JmjC（Jumonji C）结构域的基因JMJ720是一个新的受抽穗期调控的基因。JMJ720的突变导致在长日照（LD）和短日照（SD）条件下均提前开花。JMJ720蛋白在体外和体内均特异性地作为组蛋白H3赖氨酸9去甲基化酶（H3K9me2）发挥作用。此外，我们鉴定出POH1是JMJ720的一个相互作用蛋白，它招募JMJ720来调节Hd1的组蛋白甲基化水平，从而负向调节水稻开花。在全球水稻种质资源中发现了三种JMJ720单倍型（单倍型1、单倍型2和单倍型3）。单倍型1和单倍型2分别在籼稻和粳稻中占主导地位，且这两种单倍型在中国均广泛分布。总的来说，本研究揭示了参与抽穗期调控的表观遗传修饰分子网络，并为水稻分子育种提供了新的靶基因。
