Data from: Intensive aquaculture selects for increased virulence and interference competition in bacteria

Although increased disease severity driven by intensive farming practices is problematic in food production, the role of evolutionary change in disease is not well understood in these environments. Experiments on parasite evolution are traditionally conducted using laboratory models, often unrelated to economically important systems. We compared how the virulence, growth and competitive ability of a globally important fish pathogen, Flavobacterium columnare, change under intensive aquaculture. We characterized bacterial isolates from disease outbreaks at fish farms during 2003-2010, and compared F. columnare populations in inlet water and outlet water of a fish farm during the 2010 outbreak. Our data suggest that the farming environment may select for bacterial strains that have high virulence at both long and short time scales, and it seems that these strains have also evolved increased ability for interference competition. Our results are consistent with the suggestion that selection pressures at fish farms can cause rapid changes in pathogen populations, which are likely to have long-lasting evolutionary effects on pathogen virulence. A better understanding of these evolutionary effects will be vital in prevention and control of disease outbreaks to secure food production.

尽管集约化养殖模式会加剧病害严重程度，对粮食生产构成不利影响，但这类养殖环境中病害相关演化变化的作用机制仍未得到充分阐明。传统上，致病菌演化研究多依托实验室模型开展，而此类模型往往与具有经济价值的养殖体系脱节。本研究针对全球重要鱼类致病菌柱状黄杆菌（Flavobacterium columnare）的毒力、生长能力与竞争能力在集约化水产养殖环境下的变化开展了对比分析。我们对2003至2010年间各渔场病害暴发事件中分离得到的细菌菌株进行了表型特征分析，并对比了2010年某渔场暴发病害时，其进水口与出水口水体中的柱状黄杆菌种群结构。研究数据显示，养殖环境可能对兼具长、短时间尺度高毒力的细菌菌株产生正向选择，且这类菌株的干扰竞争能力也已出现演化增强。本研究结果与"渔场选择压力可引发致病菌种群快速演化"这一推论相符，此类演化过程极可能对致病菌毒力产生持久的演化效应。深入解析这类演化效应，对于通过病害暴发防控保障粮食生产而言至关重要。