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Identification of novel putative virulence factors, adhesin AIDA and type VI secretion system, in atypical strains of fish pathogenic Edwardsiella tarda by genomic subtractive hybridization
Author(s) -
Sakai Takamitsu,
Matsuyama Tomomasa,
Sano Motohiko,
Iida Takaji
Publication year - 2009
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2009.00108.x
Subject(s) - edwardsiella tarda , biology , suppression subtractive hybridization , virulence , bacterial adhesin , microbiology and biotechnology , genetics , gene , homology (biology) , olive flounder , type vi secretion system , flounder , peptide sequence , cdna library , fishery , fish <actinopterygii>
Edwardsiella tarda, which is known to be the causative agent of edwardsiellosis in freshwater and marine fish, has two motility phenotypes. Typical strains exhibiting motility are isolated mainly from freshwater fish and Japanese flounder. Atypical strains exhibiting non‐motility are isolated mainly from marine fish, with the exception of Japanese flounder. Subtractive hybridization was performed to identify genomic differences between these two phenotypes. Two fragments which showed homology to potential virulence factors were isolated from atypical strains: the autotransporter adhesin AIDA and a component of T6SS. We analysed DNA sequences of about 5 kbp containing these fragments and identified two partial ORF, and ORF encoding for other components of T6SS. The predicted amino acid sequences showed remarkably low homology to components of T6SS reported in the typical E. tarda strain PPD130/91. Furthermore, the organization of these ORF was different from the gene cluster of the typical E. tarda strain. AIDA and T6SS may therefore be associated with different pathogenicity in typical and atypical E. tarda hosts.