Joint analysis of whole-genome methylation and transcriptome in avian pullorum disease and validation of gene function

Pullorum disease caused by Salmonella pullorum can negatively affect growth and egg-laying performance, resulting in significant economic losses in poultry farming. In this study, spleen tissues from SP-infected chickens (group P) and SP-uninfected chickens (group N) were analyzed for functional enrichment using whole-genome bisulfite and RNA sequencing. The function of the key gene MSX2 was verified by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Results indicated significant changes in the spleen methylation pattern of group P, primarily characterized by hypomethylation in the promoter, intron, and exon regions. Coanalysis identified six genes (MSX2, C21orf62, PGLYRP2, KCNQ3, SEZ6L, and SLC38A11) with significant alterations in differentially methylated regions and differentially expressed genes. MSX2 gene overexpression markedly enhanced the expression and secretion of immune factors [Interferon (IFN)-α, IFN-β, Interleukin (IL)-2, IL-3, and tumor necrosis factor-α] in chicken macrophages, suggesting that MSX2 may play a role in immune regulation in chickens. This study revealed the effects of Salmonella pullorum infection on DNA methylation and gene expression in chicken spleen tissues and screened several potential therapeutic targets, providing new insights and methods for the prevention and control of Pullorum disease.