Spoilage of refrigerated : eavesdropping on acyl-homoserine lactones promotes the spoilage potential of .

and are among the predominant spoilage bacteria in refrigerated shrimp (). are incapable of producing acyl-homoserine lactone (AHL) quorum sensing signals, but can respond to environmental AHLs. In this paper, was found to produce three AHLs, i.e. -butanoyl-l-homoserine lactone (C4-HSL), -(3-oxohexanoyl)-l-homoserine lactone (O-C6-HSL) and -(3-oxooctanoyl)-l-homoserine lactone (O-C8-HSL), according to thin-layer chromatography using the bioreporter A136. The agar diffusion and β-galactosidase assays revealed that could eavesdrop on these three AHLs from . Eavesdropping on AHLs especially C4-HSL was found to boost the growth of particularly under nutrient limiting conditions (up to 40-fold increase) in the co-culture experiments. The azocasein assay revealed that produced fourfold more extracellular proteases in response to AHLs. As demonstrated by the biofilm crystal violet staining assay and confocal laser scanning microscopy, eavesdropping also decreased the biofilm-forming capacity of . By inoculation of and onto surface-sterilized shrimp, eavesdropping was found to endow a growth advantage to in vivo, resulting in a 0.5 day shortened shelf life of shrimp according to total volatile basic nitrogen levels and sensory analysis. Overall, the AHL-dependent eavesdropping increased the spoilage potential of , providing a fresh perspective on the spoilage process of refrigerated , and this may inspire the development of novel preservation techniques in the future to further reduce post-harvest loss of shrimp.