Vibriosis is a global threat to aquaculture, with Vibrio harveyi being the most significant pathogen of marine fish in the South China Sea, accounting for up to 60% of vibriosis cases. The presence of various virulence genes (VGs) and antibiotic resistance genes (ARGs) complicates disease prevention and control. Horizontal gene transfer (HGT) enables rapid acquisition of VGs and ARGs, facilitating genetic information exchange within and between species, and even among probiotics, posing severe risks to environmental safety, food safety, and human health. Controlling the HGT of VGs and ARGs is crucial for sustainable aquaculture.
Our study focused on potential Vibrio harveyi pathogens isolated from infected marine fish in the South China Sea and investigated three key areas: evaluating HGT of VGs and ARGs in Vibrio harveyi, analyzing environmental factors influencing HGT, and elucidating molecular regulatory mechanisms of HGT. Results indicated that Vibrio harveyi can acquire atypical VGs through HGT from other Vibrio species, enhancing its virulence and host range. Additionally, Vibrio harveyi spreads ARGs and VGs via mobile genetic elements (MGEs) like pAQU plasmid and integrases. Environmental stresses such as temperature, pH, SDS, and EtOH significantly boost conjugation efficiency. TfoX promotes while BsuB I-R inhibits the acquisition of foreign plasmids by Vibrio harveyi, likely by facilitating transmembrane transport and shearing of foreign plasmids, respectively.
These findings enhance our understanding of Vibrio harveyi’s pathogenicity and antibiotic resistance transmission, providing scientific foundations for developing technologies to block conjugation-transfer processes. This approach aims to establish a disease control strategy based on preventing conjugation-transfer, effectively "masking" bacteria to curb the spread of harmful genes.