FIG 6.
The QS2 genes are located on a transmissible genetic element in A. tumefaciens A6. (A) AHL production by three transconjugants (C1A6MR1 to C1A6MR3) obtained after conjugal mating with A6(traMk588 ΔtraM2 traR2::Tn5) as the donor strain and C58C1 as the recipient strain. (B) PCR examination of the donor, the recipient, and their transconjugants. The ska gene, which is unique to nopaline strain C58C1 and absent from octopine strain A6, and the traI2 and traI fragments, which are present in A6 but absent from C58C1, were, respectively, amplified by PCR. Lanes M contained molecular size markers. (C) Bacterial growth of various A. tumefaciens strains with the carbon sources indicated. Results were recorded after 5 days of growth at 28°C. (D) Tumorigenicity assay of A. tumefaciens on kalanchoe leaves. Strains A6, C58C1, C1A6MR2, and C58C1(pTiA6) were grown in LB overnight and diluted to an OD600 of 1.0. Ten-microliter volumes of bacterial cultures were inoculated onto wounded kalanchoe leaves. The plant was grown at 24°C for 4 weeks before results were recorded, and the tumors incited by A6 and C58C1(pTiA6) are circled in red.