Abstract
Acute hepatopancreatic necrosis disease (AHPND) has extended rapidly, causing alarming shrimp mortalities. Initially, the only known causative agent was Vibrio parahaemolyticus carrying a plasmid coding for the mortal toxins PirVP. Recently, it has been found that the plasmid and hence the disease, could be transferred among members of the Harveyi clade. The current study performs a genomic characterization of an isolate capable of developing AHPND in shrimp. Mortality studies and molecular and histopathological analyses showed the infection capacity of the strain. Multilocus sequence analysis placed the bacteria as a member of the Orientalis clade, well known for containing commensal and even probiotic bacteria used in the shrimp industry. Further whole genome comparative analyses, including Vibrio species from the Orientalis clade, and phylogenomic metrics (TETRA, ANI and DDH) showed that the isolate belongs to a previously unidentified species, now named Vibrio punensis sp. nov. strain BA55. Our findings show that the gene transfer capacity of Vibrio species goes beyond the clade classification, demonstrating a new pathogenic capacity to a previously known commensal clade. The presence of these genes in a different Vibrio clade may contribute to the knowledge of the Vibrio pathogenesis and has major implications for the spread of emerging diseases.
Highlights
Members of the genus Vibrio comprise currently 14 recognized clades[5], where the species are defined as clusters of strains with high phenotypic and genotypic similarities
Shrimp collected during a mortality event in 2015 in a South American farm showed the symptomatology of Acute hepatopancreatic necrosis disease (AHPND), with external signs of empty stomach, lethargy, discoloration of the hepatopancreas, with a white membrane of smooth consistency expanding through it (Fig. 1A,B)
Histopathologic evaluation showed severe necrosis of the hepatopancreas tubules, with detachment of the epithelial cells from the membrane to the lumen (Fig. 1C), making it impossible to discriminate between the distinct types of cells that are affecting the integrity of the tubules (Fig. 1E)
Summary
Members of the genus Vibrio comprise currently 14 recognized clades[5], where the species are defined as clusters of strains with high phenotypic and genotypic similarities. The presence of the pVAHPND has been discovered among V. parahaemolyticus strains, and in other related species, in particular: V. harveyi, V. owensii and V. campbellii[6,14,15,16], all species belonging to the Harveyi clade For this reason, this clade is known to be the pathogenic clade for AHPND. Our findings show that the gene acquisition capacity of Vibrio species goes beyond the clade boundaries that have been previously shown, demonstrating new infective capacity to a previously known commensal clade The presence of these genes in a Vibrio clade not previously reported as pathogenic to crustaceans may contribute to the understanding of the Vibrio pathogenesis and has major implications for the spread of emerging diseases
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
