Cui, Guoqing; Li, Danping; Zhang, Lichao; Xia, Chuan; Kong, Xiuying; Liu, Xu

Journal of Integrative Plant Biology;2023;IF 11.40

DOI:10.1111/jipb.13507

ABSTRACT

he precise control of flowering time is important for the regional adaptability and productivity of many crops. Various categories of genes related to flowering have been isolated and characterized functionally in wheat (Triticum aestivum) in response to vernalization to adjust flowering initiation. Before vernalization, the inhibitory histone modification H3K27me3 is enriched in the promoter and the first intron of the vernalization gene VRN1. In addition, GLYCINE‐ RICH RNA‐BINDING PROTEIN 2 (TaGRP2) binds directly o the “critical region” of the first intron of VRN1; the P2 motif of the VRN1 promoter and the I4 motif in its first intron form a loop structure, and together restrict the transcription of VRN1. During vernalization, the inhibitory H3K27me3 modification of VRN1 is converted into the active H3K4me3 modification, and phosphorylated VERNALIZATION‐ RELATED 2 (VER2) enters the nucleus from the cytoplasm and interacts directly with the O‐GlcNAcylation of TaGRP2 (a process likely to have been mediated by TaOGT1), relieving the inhibition of VRN1 transcription by TaGRP2. Furthermore, VRN1 produces the long noncoding RNA VAS, which recruits the TaRF2b–TaRF2a heterodimer to bind directly to the Sp1 motif of the VRN1 promoter, enhancing its transcription. In addition, VRN1 can form a complex with TaVrt2 that binds directly to the CArG box of VRN1 to increase VRN1 expression (Xiao et al., 2022). In addition, the brassinosteroid (BR) signaling pathway is known to influence flowering time, as many BR‐deficient and ‐insensitive mutants exhibit late flowering (Domagalska et al., 2007; Li et al., 2010; Chen et al., 2020), but the molecular mechanism underlying BR‐mediated flowering remains largely unclear. Here, we demonstrate that GLYCOGEN SYNTHASE KINASE 3 (GSK3) physically interacts with VRN1 and regulates its accumulation to mediate flowering in wheat