Quorum sensing is required for full virulence of Vibrio campbellii towards tiger grouper (Epinephelus fuscoguttatus) larvae

Abstract

The link between quorum sensing in Vibrio campbellii and its virulence towards tiger grouper (Epinephelus fuscoguttatus) was investigated using V. campbellii wild type and quorum‐sensing mutants with inactive quorum sensing or constitutively maximal quorum‐sensing activity, and signal molecule synthase mutants. The results showed that wild‐type V. campbellii is pathogenic to grouper larvae, causing more than 50% mortality after 4 days of challenge. Furthermore, the mortality of larvae challenged with the mutant with maximally active quorum sensing was significantly higher than that of larvae challenged with the wild type, whereas a higher survival was observed in the larvae challenged to the mutant with a completely inactive quorum‐sensing system. Grouper larvae challenged with either the signal molecule synthase triple mutant, the harveyi autoinducer‐1 (HAI‐1) synthase mutant and the autoinducer‐2 (AI‐2) synthase mutant showed higher survival than larvae challenged with the wild type. In contrast, larvae challenged with the cholerae autoinducer‐1 (CAI‐1) synthase mutant showed high mortality. This indicates that HAI‐1 and AI‐2, but not CAI‐1, are required for full virulence of V. campbellii towards grouper larvae. Our data suggest that quorum‐sensing inhibition could be an effective strategy to control V. campbellii infections in tiger grouper.

Virulence of Vibrio harveyi ORM4 towards the European abalone Haliotis tuberculata involves both quorum sensing and a type III secretion system

“…In this strain, locking cells in a ‘maximally active QS’ state (by the amino acid substitution D47A in LuxO) leads to a much lower survival rate of tiger grouper larvae ( Epinephelus fuscoguttatus ), as compared to larvae infected by the wild type strain. In contrast, locking cells to a ‘low cell density’ state (by the amino acid substitution D47E in LuxO) leads to an increased survival rate of these larvae (Noor et al ., 2019).…”

“…As a consequence, the non-phosphorylated LuxO is unable to induce the expression of the ncRNAs, leading to an increased translation of luxR (Lorenz et al, 2017). The LuxR protein regulates directly or indirectly the expression of up to 625 genes in V. campbellii (van Kessel et al, 2013;Ball and van Kessel, 2019), notably triggering an increased virulence (Noor et al, 2019) and motility (Yang and Defoirdt, 2015), and a decreased biofilm formation (Anetzberger et al, 2009).. Importantly, while this above-described regulatory network is highly conserved among Vibrio (Ng and Bassler, 2009), the downstream genes regulated by the LuxR/HapR family of proteins and the phenotypical outcomes of this gene regulation can greatly differ from species to species (Ng and Bassler, 2009;Boyaci et al, 2016;Ball et al, 2017).…”

“…As a consequence, the non‐phosphorylated LuxO is unable to induce the expression of the ncRNAs, leading to an increased translation of luxR (Lorenz et al ., 2017). The LuxR protein regulates directly or indirectly the expression of up to 625 genes in V. campbellii (van Kessel et al ., 2013; Ball and van Kessel, 2019), notably triggering an increased virulence (Noor et al ., 2019) and motility (Yang and Defoirdt, 2015), and a decreased biofilm formation (Anetzberger et al ., 2009). .…”

Whole‐genome sequencing of brown‐marbled grouper (Epinephelus fuscoguttatus) provides insights into adaptive evolution and growth differences

“…lanceolatus ♂ accounts for 70% of grouper production in China (Wang et al, 2019). Previous research on brown‐marbled grouper has mainly focused on disease resistance (Chen et al, 2019; Mohamad et al, 2019; Noor et al, 2019; Nurdalila et al, 2019; Zhang et al, 2015) and feed additives (Mamauag et al, 2019). In our laboratory, we developed molecular markers associated with growth traits (Yang, Wu, Wu, et al, 2020).…”

“…In particular, the annual output of E. fuscoguttatus♀ × E. lanceolatus♂ accounts for 70% of grouper production in China (Wang et al, 2019). Previous research on brownmarbled grouper has mainly focused on disease resistance (Chen et al, 2019;Mohamad et al, 2019;Noor et al, 2019;Nurdalila et al, 2019;Zhang et al, 2015) and feed additives (Mamauag et al, 2019).…”