TraR is essential for induction of acyl-HSL production and conjugative transfer. (A and B) NTL4(pAoF64/95) and the traR mutant, NTL4(pAoF64/95ΔtraR), were grown in AB medium containing mannitol or MOP as the primary carbon source. After overnight growth, samples were removed and tested for conjugative transfer using A. tumefaciens strain C58C1RS as the recipient (A) and levels of AAI accumulation (B). (C and D) The traR mutant was complemented with a wild-type copy of traR cloned into pSRKGm. The resulting strain, NTL4(pAoF64/95ΔtraR, pSRKGm::traR), was grown in AB minimal medium containing mannitol or MOP, each with and without IPTG, and assessed for conjugative transfer (C) and AAI accumulation (D). The experiment was done two or three times, and the mean and standard deviation for each culture condition are shown.