Table 1 Bacterial strains and plasmids used in this study

Spontaneous Sm^r mutant of M93 (serotype O2a); parental strain isolated from a diseased ayu (Plecoglossus altivelis) from Lake Biwa, Japan

Sm^r Cm^rvah1; insertional vah1 mutant of M93Sm

Sm^r Cm^r Tc^rvah1+; vah1 complement strain of JR1

Sm^r Cm^rplp; insertional plp mutant of M93Sm

Sm^r Cm^r Tc^rplp+; plp complement strain of S262

Sm^r Cm^rrtxA; insertional rtxA mutant of M93Sm

Sm^r Cm^r Km^rvah1 plp; insertional vah1mutant of JL01

Sm^r Cm^r Km^rvah1 rtxA; insertional rtxA mutant of S171

Sm^r Cm^r Km^r Tc^rvah1+ rtxA; vah1 complement strain of S183

Sm^r Cm^r Km^rplp rtxA; insertional rtxA mutant of JL01

Sm^r Cm^r Km^rvah1 plp rtxA; insertional plp mutant of S264

Sm^r Cm^r Km^r Tc^rvah1 plp + rtxA; plp complement strain of XM90

Sm^r Km^rplp; mini-Tn10Km insertion into plp

Sm^r Km^rvah1; allelic exchange vah1 mutant

Sm^r Km^rvah1 rtxA; allelic exchange vah1 and rtxA mutant

thi thr leu tonA lacY supE recA RP4-2-Tc::Mu::Km (λ pir)

Km^r Cm^r; Sm10 containing plasmid pNQ705-plp

Km^r Cm^r; Sm10 containing plasmid pNQ705-rtxA

Km^r Cm^r; Sm10 containing plasmid pDM4-rtxA5'

Km^r Cm^r; Sm10 containing plasmid pDM4-rtxA5'-rtxA3'

Km^r Ap^r Tc^r; Sm10 containing plasmid pSUP202-vah1

Km^r Ap^r Tc^r; Sm10 containing plasmid pSUP202-plp

Nal^S Str^S Rif^Sthi^–lac^–ara⁺gal⁺mtl^– F^–recA⁺uvr⁺lon⁺ (pREP4)

Km^r Ap^r; M15 containing plasmid pQE30UA-plp

Km^r Ap^r; M15 containing plasmid pQE60-plp

Km^r Ap^r; Cloning vector

Cm^r; suicide vector with R6K origin

Cm^r; for insertional vah1mutation

Cm^r; for insertional plp mutation

Cm^r; for insertional rtxA mutation

Cm^r SacBC^r; suicide vector with R6K origin

Cm^r SacBC^r; for allelic exchange rtxA mutation

Cm^r Ap^r Tc^r; E. coli – V. anguillarum shuttle vector

Ap^r Tc^r; for complementation of vah1

Ap^r Tc^r; for complementation of plp

Ap^r; expression vector with N-terminal His₆-tag

Ap^r; for expression of rPlp that is used to make anti-Plp

Ap^r; expression vector with C-terminal His₆-tag

Ap^r; for expression of rPlp for enzymatic activity analysis