Abstract: To investigate the effects of methyltransferase gene hsdM of type I RM system on the motility of Aeromonas veronii, hsdM deletion strains ΔhsdM was constructed to explore the influences on the growth, motility and flagellum gene expressions of Aeromonas veronii. Growth curves showed that the growth rate of Δ hsdM strains began to decrease slowly in the late growth stage of logarithmic phase, while the overall growth levels of wild type and ΔhsdM mutant are similar; motility assay suggested that the deletion of hsdM significantly reduced the motility of the bacteria. RT-qPCR indicated that the expressions of some flagellum genes were significantly down-regulated in ΔhsdM strains. This study preliminarily explored the basic phenotypes of hsdM deletion related with bacterial motility, providing a theoretical foundation for further study on the mechanism of 6mA methylation on regulations of gene expressions.

Key words: DNA methylation, methyltransferase, Aeromonas veronii, bacterial motility