Molecular Mechanism of luxR Regulation of Drug Resistance of Aeromonas hydrophila

Abstract:

LuxR family proteins play a key role in various important physiological activities of gram-negative bacteria. In this study, RNAi technology was used to construct a stable silenced strain Aeromonas hydrophila luxR05735-RNAi. The expression of luxR05735 in wild-type strain and luxR05735- RNAi was detected by qRT-PCR. The results showed that the expression of luxR05735 in strain luxR05735- RNAi was reduced by 96.8% compared to that of the wild-type strain. Drug sensitivity tests showed that luxR05735-RNAi significantly reduced bacterial resistance to gentamicin, norfloxacin, kanamycin, and pipemidic acid compared with the wild-type strain. The transcriptome analysis of the wild-type strain and luxR05735-RNAi revealed that there were 1286 genes with significant differences in expression, of which 353 genes were up-regulated and 933 genes were down-regulated. There are four significantly enriched pathways, which are ribosome, arginine biosynthesis, sulfur metabolism and selenocompound metabolism. In the four pathways, some important functional genes, including metE, glnA, rplB, rplX, rpsA, rpsJ were found to be associated with drugs resistance of A. hydrophila. These genes encode the proteins that were mainly involved in bacteria biofilm formation and ribosomal protein synthesis. It can be speculated from the above results that the luxR05735 of A. hydrophila regulates the expression of the genes that encode bacteria biofilm formation and ribosomal protein synthesis, and then further regulates the drugs resistance of A. hydrophila.