National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
J Integr Plant Biol. 2022 Jan;64(1):149-165. doi: 10.1111/jipb.13196.
Rice (Oryza sativa) is a major crop that feeds billions of people, and its yield is strongly influenced by flowering time (heading date). Loss of RICE INDETERMINATE1 (RID1) function causes plants not to flower; thus, RID1 is considered a master switch among flowering-related genes. However, it remains unclear whether other proteins function together with RID1 to regulate rice floral transition. Here, we revealed that the chromatin accessibility and H3K9ac, H3K4me3, and H3K36me3 levels at Heading date 3a (Hd3a) and RICE FLOWERING LOCUS T1 (RFT1) loci were significantly reduced in rid1 mutants. Notably, RID1 interacted with SET DOMAIN GROUP PROTEIN 722 (SDG722), a methyltransferase. We determined that SDG722 affects the global level of H3K4me2/3 and H3K36me2/3, and promotes flowering primarily through the Early heading date1-Hd3a/RFT1 pathway. We further established that rice DELLA protein SLENDER RICE1 (SLR1) interacted with RID1 to inhibit its transactivation activity, that SLR1 suppresses rice flowering, and that messenger RNA and protein levels of SLR1 gradually decrease with plant growth. Furthermore, SLR1 competed with SDG722 for interaction with RID1. Overall, our results establish that interplay between RID1, SLR1, and SDG722 feeds into rice flowering-time control.
水稻（Oryza sativa）是一种主要的作物，为数以亿计的人提供食物，其产量受到开花时间（抽穗期）的强烈影响。丧失 RICE INDETERMINATE1（RID1）的功能会导致植物不开花；因此，RID1被认为是与开花相关基因的主开关。然而，目前尚不清楚是否有其他蛋白质与 RID1 一起共同调节水稻的花转变。在这里，我们揭示了在 rid1 突变体中，Heading date 3a（Hd3a）和 RICE FLOWERING LOCUS T1（RFT1）基因座的染色质可及性以及 H3K9ac、H3K4me3 和 H3K36me3 水平显著降低。值得注意的是，RID1 与 SET DOMAIN GROUP PROTEIN 722（SDG722），一种甲基转移酶相互作用。我们确定 SDG722 影响 H3K4me2/3 和 H3K36me2/3 的整体水平，并主要通过 Early heading date1-Hd3a/RFT1 途径促进开花。我们进一步建立了水稻 DELLA 蛋白 SLENDER RICE1（SLR1）与 RID1 相互作用以抑制其转录激活活性，SLR1 抑制水稻开花，并且 SLR1 的 mRNA 和蛋白水平随着植物生长逐渐降低。此外，SLR1 与 SDG722 竞争与 RID1 的相互作用。总的来说，我们的结果表明 RID1、SLR1 和 SDG722 之间的相互作用有助于控制水稻的开花时间。
