Virulence regulation of Zn uptake system on mesophilic SRW-OG1.

Psychrophilic could not grow above 25°C and therefore thought unable to infect mammals and humans. In our previous study, a mesophilic SRW-OG1 was isolated from with furunculosis. Through the analysis of preliminary RNA-seq, it was found that the Zn uptake related genes and might be involved in the virulence regulation of SRW-OG1. Therefore, the purpose of this study was to explore the effect of silencing on the virulence regulation of SRW-OG1. The results showed that the growth of the -RNAi, -RNAi, and -RNAi strains was severely restricted under the Fe starvation, but surprisingly there was no significant difference under the Zn restriction. In the absence of Zn and Fe, the expression level of was significantly increased. The motility, biofilm formation, adhesion and hemolysis of the -RNAi, -RNAi, and -RNAi strains were significantly reduced. We also detected the expression of under different growth periods, temperatures, pH, as well as Cu and Pb stresses. The results showed that was significantly up-regulated in the logarithmic phase and the decline phase of . Interestingly, the trend of expression levels of the at 18, 28, and 37°C was reversed to another Zn uptake related gene . Taken together, these indicated that the was necessary for SRW-OG1 pathogenicity and environmental adaptability, and was cross regulated by iron starvation, but it was not irreplaceable for SRW-OG1 Zn uptake in the host.