FIG 5.
The QS2 system is independent of octopine induction in A. tumefaciens A6. (A) AHL production by A6(traMk588) and A6(traMk588 ΔtraI) with (+) or without (−) octopine induction on BM agar plates. (B) RT-PCR analysis of traM2, traR2, and traI2 expression with (+) or without (−) octopine induction with traI as a control. A6(pTiA6traMK588) cells were cultivated in BM medium at 28°C with or without octopine induction. Samples were collected at OD600 of 1.2 for total RNA isolation. RT-PCR analysis was carried out with the primers described in Materials and Methods. Three concentrations of RNA templates, including an original concentration of 20 ng/μl and its 10× and 100× dilutions, were used for the comparative RT-PCR analysis.