ASIM, Ifremer, La Tremblade, France.
IHPE, CNRS, IFREMER, Université de Montpellier, Montpellier, France.
Mol Ecol. 2023 Jun;32(11):2869-2883. doi: 10.1111/mec.16910. Epub 2023 Mar 30.
Crassostrea gigas oysters represent a significant global food source with 4.7 million tons harvested per year. In 2001, the bacterium Vibrio aestuarianus subsp. francensis emerged as a pathogen that causes adult oyster mortality in France and Ireland. Its impact on oyster aquaculture has increased in Europe since its re-emergence in 2012. To better understand the evolutionary mechanisms leading to the emergence and persistence over time of this pathogen, we conducted a survey of mollusc diseases through national reference laboratories across Europe. We analysed 54 new genomes of Vibrio aestuarianus (Va) isolated from multiple environmental compartments since 2001, in areas with and without bivalve mortalities. We used a combination of comparative genomics and population genetics approaches and show that Va has a classical epidemic population structure from which the pathogenic Va francensis subspecies emerged and clonally expanded. Furthermore, we identified a specific cus-cop-containing island conferring copper resistance to Va francensis whose acquisition may have favoured the emergence of pathogenic lineages adapted and specialized to oysters.
太平洋牡蛎是一种重要的全球食物来源，每年的产量为 470 万吨。2001 年，一种名为弗氏港湾弧菌亚种的细菌出现，成为法国和爱尔兰导致成年牡蛎死亡的病原体。自 2012 年再次出现以来，其对牡蛎水产养殖的影响在欧洲有所增加。为了更好地了解导致这种病原体出现和长期存在的进化机制，我们通过欧洲各国参考实验室对软体动物疾病进行了调查。我们分析了自 2001 年以来从多个环境隔室中分离出的 54 株新弗氏港湾弧菌（Va）基因组，这些基因组来自有和没有双壳类动物死亡的地区。我们结合了比较基因组学和群体遗传学方法，结果表明 Va 具有经典的流行种群结构，致病性的 Va 弗朗西斯亚种就是从这种结构中出现并克隆性扩张的。此外，我们还发现了一个特定的 cus-cop 基因岛，赋予 Va 弗朗西斯亚种铜抗性，其获得可能有利于适应和专门针对牡蛎的致病性谱系的出现。
