PrkA negatively regulates the temperature tolerance and virulence of Aeromonas veronii

Aeromonas veronii is considered an emerging food-borne pathogen associated with a significant threat to public health, distributed in various aquatic environments and products. Hanks-type serine/threonine kinases (STKs) play a critical role in the pathogenesis of pathogens. However, the function of A. veronii STKs is currently unclear. By constructing a markerless prkA in-frame deletion strain, ΔprkA, we found that ⅰ) the colonies of the ΔprkA strain were larger after 1 h of high temperature at 50 ℃ compared with the wild-type strain TH0426 and the complementary strain C-prkA, and the number of viable bacteria of the ΔprkA strain increased significantly; ⅱ) the ΔprkA strain significantly enhanced the adhesion ability to epithelioma papulosum cyprini (EPC) cells; ⅲ) the ΔprkA strain was significantly more virulent than the TH0426 strain, at both the cellular and animal levels; and ⅳ) RNA-seq results showed a total of 984 differentially expressed genes (DEGs) between the ΔprkA strain and the TH0426 strain, which were enriched in 70 Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways, mainly involved in bacterial ribosomes, flagellar assembly, type Ⅱ secretion system (T2SS), and lipopolysaccharide metabolic pathways. Taken together, the findings of this study indicate that the Hanks-type STK PrkA negatively regulates several biological processes, such as the temperature tolerance and virulence of A. veronii. The results of this study provide an important reference for further elucidation of the pathogenesis of A. veronii.