Fig. 6: Loss of function of HtL1 influences histone modification states at the VRN1 locus.

a Detection of overall levels of H3K9ac, H3K14ac, H3K27ac, and H3K4me3 modification in HtL1-RNAi and KN199 plants vernalized for 21 days. Three biological replicates were performed. Histone H3 was probed as a loading control, and the levels of histone modifications were normalized to H3. b Schematic diagram of VRN1, showing fragments detected in ChIP-qPCR analysis. Exons are represented by blue boxes, and the regions examined by ChIP are indicated by numbered red bars. ChIP-qPCR assays of H3K27ac (c), H3K14ac (d) and H3K4me3 (e) levels in the indicated regions at VRN1 in HtL1-RNAi and KN199 plants following 21 days of vernalization. Three biological replicates were performed. Data are mean ± SD, *P < 0.05, **P < 0.01, ***P < 0.001 by two-tailed Student’s t-test. The relative abundance was normalized to the input. f A working model for understanding the role of HtL1 in vernalization-mediated flowering and breeding selection analysis of HtL1. (f-1) The activity of fructose 1,6-biphosphate aldolase is regulated by phosphorylation and O-GlcNAc modifications during vernalization. Before vernalization, HtL1 was phosphorylated by TaCDPK13, and its aldolase activity was inhibited. During the vernalization process, the phosphorylation modification level of HtL1 gradually decreased, while O-GlcNAc modification of HtL1 was enhanced, resulting in increased activity and stability of HtL1. The increased activity of aldolase HtL1 promotes the enrichment of H3K14ac and H3K27ac at the VRN1 locus, leading to the activation of VRN1 transcription and consequently accelerating flowering in wheat. (f-2) Wheat varieties possessing variations in the HtL1 promoter regions exhibit differences in flowering time. The red vertical lines in the promoter region denote single-nucleotide polymorphisms (SNPs) at these sites in these varieties relative to the Chinese Spring reference genome. The utilization of wheat varieties with the Hap-2, which is associated with delayed flowering, has gradually decreased during the modern breeding process in China. Source data are provided with this figure.