AUTHOR=Dong Xuan , Song Jipeng , Chen Jiayuan , Bi Dexi , Wang Wenchao , Ren Yanbei , Wang Hailiang , Wang Guohao , Tang Kathy F. J. , Wang Xuepeng , Huang Jie 

TITLE=Conjugative Transfer of the pVA1-Type Plasmid Carrying the pirABvp Genes Results in the Formation of New AHPND-Causing Vibrio

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=9

YEAR=2019

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2019.00195

DOI=10.3389/fcimb.2019.00195

ISSN=2235-2988

ABSTRACT=<p>Acute hepatopancreatic necrosis disease (AHPND) has caused sharp declines in aquaculture industries of whiteleg shrimp <italic>Penaeus vannamei</italic> in Asia and the Americas since 2010. <italic>Vibrio parahaemolyticus, V. campbellii, V. owensii</italic>, and <italic>V. punensis</italic> have been proved to cause AHPND. However, the mechanisms underlying the burgeoning number of <italic>Vibrio</italic> species that cause AHPND is not known. All of AHPND-causing <italic>Vibrio</italic> bacteria (<italic>V</italic><sub>AHPND</sub>) harbor a highly homologous plasmid (designated as pVA1-type) carrying <italic>pirAB</italic><sup><italic>vp</italic></sup> toxin genes. In this study, we demonstrate conclusively that the pVA1-type plasmid can be transferred from <italic>V</italic><sub>AHPND</sub> to non-pathogenic bacteria. We constructed a pVPGX1-<italic>Cm</italic><sup><italic>r</italic></sup> plasmid (a pVA1-type plasmid) by adding a chloramphenicol resistance gene as a marker in a donor AHPND-causing <italic>V. parahaemolyticus</italic> 20130629002S01 (<italic>Vp</italic>2S01). Horizontal transfer of this plasmid was successfully performed from the AHPND-<italic>Vp</italic>2S01 to a non-pathogenic strain of <italic>V. campbellii</italic> at the transfer efficiency of 2.6×10<sup>−8</sup> transconjugant/recipient, and DNase I treatment did not eliminate the transfer. The recipient <italic>V. campbellii</italic> acquired the pVA1-type plasmid and was shown to produce <italic>pirAB</italic><sup><italic>vp</italic></sup> RNA and proteins. Challenge studies using the transconjugant caused 100% mortality in exposed groups of <italic>P. vannamei</italic>. The challenged shrimp, infected with the transconjugant bacteria, showed typical gross signs and histological lesions of AHPND. These results demonstrated the conjugative transfer of an AHPND pVA1-type plasmid. It provides timely information for explaining the increased species of AHPND-causing <italic>Vibrio</italic> bacteria and will be useful in the development of management strategies leading to the prevention and control of AHPND.</p>