Table 2.

Activation of the AHL monitor strains in cross-streak experimentsa

Rhizosphere isolateResult obtained with:
MG44 (pJBA132)KS35F117 (pKR-C12)F117 (pAS-C8)
P. putidaIsoF++++++++++++
P. putida Z2D++++++++++
R. aquatilis T13+++++
R. aquatilisTAA++++++++++
  • a The four monitor strains, MG44(pJBA132), F117(pKR-C12), F117(pAS-C8), and KS35 (F117::Tn5-LAS), were cross-streaked against various rhizosphere isolates on LB agar plates. Following 24 h of incubation at 30°C, the production of Gfp(ASV) by the monitor strains was visualized by epifluorescence microscopy. Levels of activation are indicated as follows: +++, strong activation, diffusion of AHL of >1 cm; ++, activation, diffusion of AHL of 0.5 to 1 cm; +, weak activation, diffusion of AHL of <0.5 cm; −, no detectable activation.