Table 1 Bacterial strains and plasmids

 XL1-Blue

recA1, endA1 gyrA96 thi-1 hsdr17 sup E44 relA1 lac^q ZΔ M15 Tn 10 (Tet^r)]

Stratagen

 Rsp. rubrum

Wild type

ATCC11170

REGO^-

mutants R. rubrum regO Ω, sm^r, sp^r

This work

REGO pRK415 regO

regO Ω, sm^r, sp^r , pRK415 Tet^rregO PCR fragment

This work

 pBluescript KSII

Cloning vector (Ap^r); with T3 and T7 promotors

Stratagen

 pHP45Ω

Source of the Ω Sm^r Sp^r cassete

(Prentki and and Henry M. Krisch 1984)

 pSUP202

Suicide vector for R. rubrum, ap^r cm^r tc^r; mob⁺

(Simon et al. 1983)

 pRK2013

kan^r; tra⁺

(Lois et al. 1993)

 pRK415

tet^r

l (Lois et al. 1993)

 pBS-515

1545 bp PCR fragment from R. rubrum was cloned in pBSKS(+), ap^r

This work

 pBS-515Ω

3545 bp, PCR fragment of R. rubrum with Ω, sm^r sp^r at NdeI site of regO was cloned in pBSKS(+), ap^r

This work

 pPSUP-515Ω

3500 bp, PCR fragment of R. ` with Ω, sm^r sp^r at NdeI site of regOwas cloned in pSUP202, ap^r,cm^r

This work