Histone H3 lysine 27 trimethylation (H3K27me3) modulates the fiber initiation in upland cotton
Histone methylation is one of the most significant epigenetic modifications in plants because it is responsible for regulating and controlling the expression of many important functional genes. Although there have been many studies concerning histone methylation, its specific functions and mechanisms in cotton fiber initiation remain unclear. To determine if the H3K27me3 modification had regulated cotton fiber initiation in upland cotton (Gossypium hirsutum), we performed a comparative analysis on the cleavage under targets and tagmentation (CUT&Tag) between the wild-type cultivar Xu142 and its fibreless mutant Xu142 fl. This research was carried out three time points during the initiation period of cotton fibers, which were -1, 0 and 1 days post-anthesis (DPA). We also used the H3K27me3 antibody in Xu142 and Xu142 fl to examine the differential deposition of H3K27me3. Combing these results with RNA-seq analysis, we discovered a negative correlation between transcription and H3K27me3. We identified 336 genes with opposing trends in H3K27me3 deposition and expression. These genes are involved in various metabolic pathways, including fatty acid biosynthesis, galactose metabolism, plant hormone signal transduction, plant-pathogen interaction, glycolysis-/-gluconeogenesis, phenylpropanoid biosynthesis, and cutin, suberin and wax biosynthesis. Further physiological research revealed that in vitro ovule culture with an RDS 3434 inhibitor could alters the level of H3K27me3 in ovules, thus influencing the process of cotton fiber development. Taken together, these results indicate that H3K27me3 plays an important role in the fiber initiation process of cotton, and demonstrates the H3K27me3 network involved in fiber initiation in cotton ovules. The study also provides a foundation for the future study of genes involved in fiber development. Overall design: Comparative gene expression profiling analysis of RNA-seq data for Xu142 and Xu142 fl at -1 DPA?0 DPA?1 DPA.