TABLE 1.

Bacterial strains and plasmids used in this study

Strain or plasmidRelevant characteristicsSource or reference
Strains
    E. coli
        CF1648Wild-type K-12 strain (MG1655) 59
        CF1652ΔrelA251::kan derivative of CR1648 59
        CF1693ΔspoT207::cat derivative of CF1652 59
        Top10F mcrA Δ(mrr-hsdRMS-mcrBC) φ80lacZΔM15ΔlacX74 recA1 araD139 galU galK Δ(ara-leu)7697 rpsL (Strr) endA1 nupG Invitrogen
        EC100D pir+ F mcrA Δ(mrr-hsdRMS-mcrBC) φ80dlacZΔM15ΔlacX74 recA1 endA1 araD139 Δ(ara-leu)7697 galU galK λ rpsL nupG pir + (DHFR)Epicentre
        JM109 recA1 supE44 endA1 hsdR17 gyrA96 relA1 thi Δ(lac-proAB) F′ [traD36 proAB + lacI q lacZΔM15] 62
    Sphingomonas sp.
        Rr 2-17Wild-type isolate from nopaline grapevine tumorThis work
        Hx 699Mutant isolate 699, rsh::EZ-Tn5, Kmr derivative of Rr2-17, deficient in AHL synthesisThis work
    A. tumefaciens NTL4(pZLR4)Indicator strain for detection of AHLs 7
    Chromobacterium violaceum
        Wild typeATTC 31532, produces violacein pigment and C6-HL signalATCC
        CV026Indicator strain for detection of alkanoyl-AHLs, derivative of 31532 with mini-Tn5, Kmr, cviI 31
Plasmids
    pHG112-kb EcoRI fragment from digestion of Hx 699 genomic DNA containing EZ-Tn5 transposon, Kmr This work
    pCR2.1pUC ori, Kmr Ampr Invitrogen
    pHG2Same as pCR2.1 but with EcoRI deletionThis work
    pHG3pCR2.1 with rsh and native promoter, Kmr Ampr This work
    pRK290Broad host range, oriT and oriV, Tcr 14
    pHG4pRK290 with rsh and native promoter, Tcr This work
    pSB401 luxR + PluxI-luxCDABE Tcr p15A ori 58