Fig. 6: Butyrate regulates lipid metabolism through H3K27ac modification in honey bee fat bodies.

a H3K27ac levels in fat bodies of GF and butyrate-supplemented bees, assessed by western blot (total H3 as the loading control). The relative gray values of western blot were measured using Image J. Bars represent mean ± s.e.m. The images presented are from one of the three independent experiments (see Supplementary Fig. 15a for replicate data). Each sample pooled from 5 individuals from 3 cup cages. P = 0.0011 from two-sided Student’s t test. b Principal Component Analysis based on normalized CUT&Tag peak counts from the fat bodies of GF and butyrate-supplemented bees 5 days post-supplementation. c Overlapping peaks of H3K27ac in GF (blue) and butyrate-supplemented (red) groups, with IgG (gray) as the negative control. d Distribution of H3K27ac peaks across genomic features (promoters, exons, introns, intergenic regions, 5’UTRs, and 3’UTRs) for each sample group. e KEGG analysis of upregulated genes with differential H3K27ac peaks. P values were determined using a one-sided hypergeometric test. f Heatmap of differential H3K27ac peaks in glycerophospholipid metabolism genes. g Genomic tracks of LOC724951 and LOC724907 from H3K27ac CUT&Tag sequencing. h, i ChIP-qPCR of H3K27ac at LOC724951 (h) and LOC724907 (i) promoters. Bars represent mean ± s.e.m. n = 3 replicates for each group, with each replicate pooled from 5 individuals from 3 cup cages (two independent experiments, see Supplementary Fig. 15b for replicate data). P = 0.0044 (h) and 0.0122 (i) from two-sided Student’s t test. j Schematic model illustrating how gut bacteria produce butyrate to prime systemic immunity in honey bees. Source data are provided as a Source Data file. Created in BioRender. Liu, L. (2025) https://BioRender.com/3gkn9pc.