Laboratory of Microbiology, Institute of Biology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
ISME J. 2011 Sep;5(9):1471-83. doi: 10.1038/ismej.2011.19. Epub 2011 Mar 31.
Vibrio coralliilyticus has been implicated as an important pathogen of coral species worldwide. In this study, the nearly complete genome of Vibrio coralliilyticus strain P1 (LMG23696) was sequenced and proteases implicated in virulence of the strain were specifically investigated. The genome sequence of P1 (5,513,256 bp in size) consisted of 5222 coding sequences and 58 RNA genes (53 tRNAs and at least 5 rRNAs). Seventeen metalloprotease and effector (vgrG, hlyA and hcp) genes were identified in the genome and expressed proteases were also detected in the secretome of P1. As the VcpA zinc-metalloprotease has been considered an important virulence factor of V. coralliilyticus, a vcpA deletion mutant was constructed to evaluate the effect of this gene in animal pathogenesis. Both wild-type and mutant (ΔvcpA) strains exhibited similar virulence characteristics that resulted in high mortality in Artemia and Drosophila pathogenicity bioassays and strong photosystem II inactivation of the coral dinoflagellate endosymbiont (Symbiodinium). In contrast, the ΔvcpA mutant demonstrated higher hemolytic activity and secreted 18 proteins not secreted by the wild type. These proteins included four types of metalloproteases, a chitinase, a hemolysin-related protein RbmC, the Hcp protein and 12 hypothetical proteins. Overall, the results of this study indicate that V. coralliilyticus strain P1 has a diverse virulence repertoire that possibly enables this bacterium to be an efficient animal pathogen.
珊瑚弧菌已被认为是世界范围内珊瑚物种的重要病原体。在本研究中，对珊瑚弧菌 P1 株（LMG23696）的近完整基因组进行了测序，并专门研究了与该菌株毒力相关的蛋白酶。P1 的基因组序列（大小为 5,513,256 bp）由 5222 个编码序列和 58 个 RNA 基因（53 个 tRNA 和至少 5 个 rRNA）组成。在基因组中鉴定出 17 种金属蛋白酶和效应物（vgrG、hlyA 和 hcp）基因，并且在 P1 的分泌组中也检测到表达的蛋白酶。由于 VcpA 锌金属蛋白酶被认为是珊瑚弧菌的重要毒力因子，因此构建了 vcpA 缺失突变体来评估该基因在动物发病机制中的作用。野生型和突变型（ΔvcpA）菌株均表现出相似的毒力特征，导致卤虫和果蝇致病性生物测定中的高死亡率以及珊瑚虫内共生鞭毛藻（Symbiodinium）的强光系统 II 失活。相比之下，ΔvcpA 突变体表现出更高的溶血活性，并分泌了野生型未分泌的 18 种蛋白质。这些蛋白质包括四种类型的金属蛋白酶、几丁质酶、溶血素相关蛋白 RbmC、Hcp 蛋白和 12 种假定蛋白。总体而言，本研究的结果表明，珊瑚弧菌 P1 株具有多样化的毒力谱，这可能使该细菌成为有效的动物病原体。
