摘 要：接触依赖型抑制在菌群竞争和宿主定殖过程中发挥重要作用，但其在鱼类病原菌防控中的应用及分子机制报道较少。本研究旨在评估摩氏假单胞菌（Pseudomonas mosselii）对维氏气单胞菌（Aeromonas veronii）的接触依赖型抑制活性及宿主保护作用，并初步解析其分子基础。通过细菌竞争试验，检测摩氏假单胞菌对大肠杆菌（Escherichia coli）和维氏气单胞菌的接触依赖型抑制表型，并采用斑马鱼（Danio rerio）感染模型评估摩氏假单胞菌对维氏气单胞菌侵袭的保护效果。在此基础上，进一步利用同源重组技术构建多种毒力分泌系统缺失突变株，分析不同分泌系统在接触依赖型抑制中的作用。结果表明，摩氏假单胞菌对大肠杆菌和维氏气单胞菌均具有显著的接触依赖型抑制活性。在斑马鱼感染试验中，摩氏假单胞菌能够提高宿主在维氏气单胞菌感染中的存活率。以大肠杆菌为靶标菌时，VI型分泌系统（T6SS）在接触依赖型抑制表型中发挥主要作用；在以维氏气单胞菌为靶标菌时，I、II、III、IV、V、VI型毒力分泌系统缺失突变株与野生型菌株的接触依赖型抑制活性无显著差异。本研究为利用接触依赖型抑菌活性开发鱼类病原菌防控新策略提供了试验基础。
关键词：摩氏假单胞菌；维氏气单胞菌；接触依赖型抑菌活性；毒力分泌系统；基因敲除
中图分类号：Q939.92      文献标志码：A    DOI：10.3969/j.issn.1007-7146.2026.04.004

Abstract: Contact-dependent inhibition plays an important role in bacterial competition and host colonization. However, its application in the control of fish bacterial pathogens and the underlying molecular mechanisms remain poorly understood. This study aimed to evaluate the contact-dependent inhibitory activity of Pseudomonas mosselii (P. mosselii) against Aeromonas veronii (A. veronii) and its protective effect on the host, as well as to preliminarily investigate the molecular basis of this antagonistic activity. Bacterial competition assays were performed to assess the contact-dependent inhibitory activity of P. mosselii against Escherichia coli (E. coli) and A. veronii. A zebrafish infection model was employed to evaluate the protective effect of P. mosselii against A. veronii infection. Furthermore, multiple mutants lacking different virulence secretion systems were constructed by using homologous recombination technology for analyzing the role of these secretion systems in contact-dependent inhibition. The results showed that P. mosselii exhibited significant contact-dependent inhibitory activity against both E. coli and A. veronii. In the zebrafish infection model, P. mosselii significantly increased host survival following A. veronii infection. When E. coli was used as the target strain, type VI secretion system (T6SS) played an important role in contact-dependent inhibition. In contrast, when A. veronii was used as the target strain, no significant difference in contact-dependent inhibitory activity was observed between the wild-type strain and mutants lacking type I～VI virulence secretion systems. This study provides an experimental basis for the development of a new strategy for controlling fish bacterial pathogens based on contact-dependent antibacterial activity.
Keywords: Pseudomonas mosselii; Aeromonas veronii; contact-dependent antibacterial activity; virulence secretion systems; gene knockout
（Acta Laser Biology Sinica, 2026, 35(4): 319-325）