Rich resource environment of fish farms facilitates phenotypic variation and virulence in an opportunistic fish pathogen

摘要: Summary Phenotypic variation allows adaptation of opportunistic pathogens to variable conditions in the outside-host environment with strong effects on their epidemiology and pathogenicity hosts. Here we found that isolates an fish pathogen Flavobacterium columnare from farming had higher phenotypic between two morphotypes growth, as compared natural water environment. The rough growth rate than rhizoid especially resource concentrations temperature, but only if isolate was originating farms. Rhizoid morphotype more virulent type regardless origin. However, virulence increased sharply size fish, bacterial gills diseased were type, indicating a reversal into contact fish. high combined reversibility could increase probability columnaris epidemics at Our findings suggest intensive imposes different selection pressures survival its transmission