Identification and Expression Analysis of an Interacting Protein (LvFABP) that Mediates Vibrio parahaemolyticus AHPND Toxin Action

Abstract

Acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio parahaemolyticus causing AHPND (VPAHPND) is the most serious disease affecting shrimp farming. The PirAvp and PirBvp toxins of VPAHPND are known virulence factors. However, the corresponding target protein in shrimp that mediates their action has not been identified. By screening yeast two-hybrid cDNA libraries from intestine, stomach, and hepatopancreas of Litopenaeus vannamei, the protein with the largest increase in gene expression in shrimp hepatopancreas in response to VPAHPND challenge was identified and designated LvFABP. Analysis revealed high sequence homology of the LvFABP gene and a lipocalin/cytosolic fatty acid binding gene. Yeast two-hybrid pairwise analysis, GST-pull down assay, and far-western blot assay were performed to determine the interaction between LvFABP and PirBvp. LvFABP was able to directly bind to PirBvp. The expression of LvFABP in the hepatopancreas was significantly higher at P23 and P27 developmental stages of L. vannamei. RNA interference (RNAi) of LvFABP reduced the mortality, histopathological signs of AHPND in the hepatopancreas, and the number of virulent VPAHPND bacteria in the intestine, stomach, and hepatopancreas after VPAHPND challenge. We concluded that the LvFABP was involved in AHPND pathogenesis and acted as a VPAHPND toxin interacting protein. This is the first identification of VPAHPND toxin interacting protein from the shrimp digestive system by yeast two-hybrid library screening and were confirmed by in vitro protein interaction verification and in vivo challenge experiments. This study provides novel insight into the contributions of LvFABP towards AHPND pathogenesis in shrimp. The findings could inform AHPND preventative measures in shrimp farming.

A bacterial binary toxin system that kills both insects and aquatic crustaceans: Photorhabdus insect-related toxins A and B

“…Knocking down of Lv FABP reduced shrimp mortality and histopathological signs of AHPND, as well as the number of the AHPND-causing V . parahaemolyticus in the challenged shrimp [ 64 ] . FABPs may occur as membrane associated or cytosolic proteins, whereas the cell localization of Lv FABP is still unclear.…”

“…FABPs may occur as membrane associated or cytosolic proteins, whereas the cell localization of Lv FABP is still unclear. Therefore, it remains to be further investigated whether Lv FABP can be a receptor of PirA vp /PirB vp toxin [ 64 ] .…”

A review on the application of chicken immunoglobulin Y in aquaculture

“…IgY is known to bind to pathogens, neutralise toxins produced by pathogens and inhibit the binding of endotoxins to target cells while avoiding adverse subsequent reactions and secondary infections; thus, IgY is an important component of the immune environment. AHPND caused by Vibrio parahaemolyticus causes huge losses in shrimp farming, and the PirAvp and PirBvp toxins of V. parahaemolyticus are known virulence factors 60 . In a previous study, Nakamura et al added 10% anti‐ PirA ‐yolk powder to shrimps for 3 days and found that IgY specifically bound and neutralised the natural PirA toxin released from the shrimp digestive system, thus resulting in a 75% reduction in shrimp mortality when compared to the control group 15 …”

“…IgY is known to bind to pathogens, neutralise toxins produced by pathogens and inhibit the binding of endotoxins to target cells while avoiding adverse subsequent reactions and secondary infections; thus, IgY is an important component of the immune environment. AHPND caused by Vibrio parahaemolyticus causes huge losses in shrimp farming, and the PirAvp and PirBvp toxins of V. parahaemolyticus are known virulence factors 60. In a previous study,Nakamura et al added 10%…”

Using loop‐mediated isothermal amplification combined with gold nanoparticles for optically rapid detection of shrimp Vibrio parahaemolyticus

“…In order to reduce the financial loss on shrimp feeding, many studies have investigated how the shrimp are infected by VP AHPND and the corresponding pathological mechanisms of VP AHPND (Gu, Liu, Wang, Jiang, & Wang, 2022; Wang et al, 2022). Early detection can lower the crop loss and prevent the disease continuous to spread.…”