Inter-Research > DAO > v144 > p9-19  
DAO
Diseases of Aquatic Organisms

via Mailchimp

DAO 144:9-19 (2021)  -  DOI: https://doi.org/10.3354/dao03574

Francisellosis of Yesso scallops Mizuhopecten yessoensis in Japan is caused by a novel type of Francisella halioticida

Miku Kawahara1, Kazutoshi Yoshitake2, Tomoyoshi Yoshinaga1, Naoki Itoh1,*

1Laboratory of Fish Diseases, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
2Laboratory of Aquatic Molecular Biology and Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
*Corresponding author:

ABSTRACT: Francisella halioticida, the causative agent of francisellosis of the giant abalone Haliotis gigantea, has also been isolated from Yesso scallops Mizuhopecten yessoensis, which presented with orange/pinkish lesions in the adductor muscle and experienced high mortality. However, it is not clear whether the F. halioticida isolated from the giant abalone and Yesso scallops are phenotypically and genetically identical to each other. The present study revealed that isolates from the giant abalone and Yesso scallops were phenotypically different, with slower growth in modified eugon broth and a lack of prolyl aminopeptidase and phenylalanine aminopeptidase in Yesso scallop isolates. Additionally, we found that 3 of 8 housekeeping genes were different between them. Based on these phenotypic and genetic differences, we propose that F. halioticida isolated from Yesso scallops in Japan be designated as the ‘J-scallop type’ to distinguish it from strains from abalone (‘abalone type’). Whole-genome sequencing analysis of a strain belonging to the J-scallop type showed that the overall similarity between the J-scallop and abalone type strains was estimated to be 99.84%. In accordance with a lack of prolyl aminopeptidase activity, in general, all of the J-scallop type strains examined have a 1 bp deletion in the responsible gene encoding prolyl aminopeptidase. This deletion was confirmed in all F. halioticida in diseased Yesso scallops examined, suggesting that in Japan, francisellosis of Yesso scallops is caused by a novel type of F. halioticida and not by the abalone type.


KEY WORDS: Bacteria · Francisellaceae · Mollusk · Bivalve · Abalone · Prolyl aminopeptidase · Genotyping


Full text in pdf format 
Cite this article as: Kawahara M, Yoshitake K, Yoshinaga T, Itoh N (2021) Francisellosis of Yesso scallops Mizuhopecten yessoensis in Japan is caused by a novel type of Francisella halioticida. Dis Aquat Org 144:9-19. https://doi.org/10.3354/dao03574

Export citation
Mail this link - Contents Mailing Lists - RSS
Facebook - - linkedIn