Population structure of the fish pathogen Flavobacterium psychrophilum at whole-country and model river levels in Japan
2013
Fujiwara-Nagata, Erina | Chantry-Darmon, Céline | Bernardet, Jean-François | Eguchi, Mitsuru | Duchaud, Éric | Nicolas, Pierre, P. | Unité de recherche Virologie et Immunologie Moléculaires (VIM (UR 0892)) ; Institut National de la Recherche Agronomique (INRA) | Kinki University | Unité Mathématique Informatique et Génome (MIG) ; Institut National de la Recherche Agronomique (INRA) | KAKENHI [18780153]; Global Center of Excellence (COE) Program, Japan; Japan Society for the Promotion of Science for Young Scientists; ANR [ANR-07-GMGE-004 Flavophylogenomics]; EU EMIDA ERA-NET [ANR 2010-EMID-006-01 Pathofish]
International audience
显示更多 [+] 显示较少 [-]英语. The bacterium Flavobacterium psychrophilum is a serious problem for salmonid farming worldwide. This study investigates by multilocus sequence typing (MLST) the population structure of this pathogen in Japan where it is also a major concern for ayu, a popular game fish related to salmoniforms. A total of 34 isolates collected across the country and 80 isolates sampled in a single model river by electrofishing were genotyped. The data accounting for 15 fish species allowed identifying 35 distinct sequence types (ST) in Japan. These ST are distinct from those reported elsewhere, except for some ST found in rainbow trout and coho salmon, two fish that have been the subject of intensive international trade. The pattern of polymorphism is, however, strikingly similar across geographical scales (model river, Japan, world) in terms of the fraction of molecular variance linked to the fish host (similar to 50%) and of pairwise nucleotide diversity between ST (similar to 5 Kbp(-1)). These observations go against the hypothesis of a recent introduction of F. psychrophilum in Japan. Two findings were made that are important for disease control: 1) at least two independent F. psychrophilum lineages infect ayu and 2) co-infections of the same individual fish by different strains occur.
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