N-Acyl homoserine lactone-mediated quorum sensing in pathogenic Aeromonas veronii biovar sobria strain 159 : identification of LuxIR homologs

16 Quorum sensing (QS) is a mechanism that plays important roles in gene expression in response to an 17 expanding bacterial population. In many Gram-negative bacteria, N-acyl homoserine lactone is mainly 18 secreted as the diffusible signalling molecules. This QS system has been shown to control diverse array 19 of virulence and secondary metabolism. Recently, whole genome sequencing of Aeromonas veronii 20 biovar sobria strain 159 was performed. Genome comparison with closely-related Aeromonas species 21 showed that A. veronii strain 159 shares a high degree of genome synteny with A. hydrophila ATCC 22 7966. A detailed genome analysis and gene annotation led us to the findings that A. veronii strain 159 23 harbors QS system which relies on its signal generator, AveI and the transcriptional regulator, AveR. 24 This Aeromonas strain was found to secrete N-butanoylacyl homoserine lactone (C4-HSL). Its LuxIR 25 homologs are similar to proteins of LuxIR famililies among Aeromonas species. This study aims to 26 gain further insights into AveIR system and to compare with AhyIR from A. hydrophila ATCC 7966 27 and AsaIR from A. salmonicida. 28 29 30 31