Abstract
Background: Grass carp is an important farmed fish in China that infected by many pathogens, especially grass carp reovirus (GCRV). Notably, grass carp showed age-dependent susceptibility to GCRV, while the mechanism remains unclear. Herein, we performed a genome-wide survey of differences in DNA methylation and gene expression between five months old grass carp (FMO, sensitive to GCRV) and three years old grass carp (TYO, resistant to GCRV) aim to uncover the mechanism.Results: Colorimetric quantification revealed global methylation level of TYO fish was higher than that of FMO fish. Whole-genome bisulfite sequencing (WGBS) of two groups revealed 6,214 differentially methylated regions (DMRs) and 4,052 differentially methylated genes (DMGs), with most of DMRs and DMGs showed hypermethylation patterns in TYO fish. Correlation analysis indicated that DNA hypomethylation in promoter negative correlated with gene expression, whereas positive correlation was found between gene-body DNA hypermethylation and gene expression. Enrichment analysis revealed that promoter hypo-DMGs in TYO fish were significant enriched in pathways involved in immune response while gene-body hyper-DMGs in TYO fish were significant enriched in terms related to RNA transcription, biosynthetic, and energy production. RNA-seq indicated these terms or pathways involved in immune response, biosynthetic, and energy production also significant enriched for the up-regulated genes in TYO fish. Conclusions: Collectively, these results revealed the genome-wide DNA methylation variations between grass carp with different ages. DNA methylation and gene expression variations in genes involved in immune response, biosynthetic, and energy production may contributed to the age-dependent susceptibility to GCRV in grass carp. Our results will provide important information for the disease-resistant breeding programs of grass carp and may also benefit to the research of age-dependent diseases in human.
Genome-Wide DNA Methylation Variations Between Grass Carp with Different Ages
