The potential association between Wolbachia infection and DNA methylation in Hylyphantes graminicola (Araneae: Linyphiidae)

Abstract

DNA methylation plays an important role in biological regulation in vertebrates, while its presence is variable among insects. However, only a few studies have reported such methylation in spiders. Here, we detected DNA methylation levels and patterns in the small-sized spider Hylyphantes graminicola (Araneae: Linyphiidae) through methylation-sensitive amplified fragment length polymorphism (MSAP). Given the prevailing rate of Wolbachia infection in H. graminicola and the potential impact on host DNA methylation, four H. graminicola groups, i.e., Wolbachia-uninfected (W−) males, Wolbachia-infected (W+) males, W− females, and W+ females, were used for detection of DNA methylation. In addition, quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of the DNA methyltransferase 1 (Dnmt1) gene in the four groups. Results demonstrated the existence of genomic DNA methylation in H. graminicola. The hemi- or fully methylated ratios at the internal cytosine (HMeCG or MeCG) was significantly higher than the hemi-methylated ratio at the external cytosine (HMeCCG) in both W− and W+ spiders. Compared to W− male and female spiders, hemi- or fully methylated ratios at the internal cytosine in W+ males and females were significantly lower, and Dnmt1 expression was significantly lower in W+ males and females than in W− males and females. These results suggest that a potential association may exist between Wolbachia infection and DNA methylation in H. graminicola.