FIG. 1.
(A) Confocal laser scanning microscopy image of P. fluorescens F113rif(pBG1157) in the alfalfa rhizosphere in a gnotobiotic system (Leonard jar). Expression of the gfp gene under the nodbox system resulted in green fluorescence visible in individual cells and microcolonies. (B) Epifluorescence image of P. fluorescens F113L::1180(pHC60) in the alfalfa rhizosphere in a PCB-spiked soil microcosm. Expression of the gfp gene from a constitutive lac promoter resulted in green fluorescence observed in bacteria colonizing the root surface (toward the root tip) 14 days after inoculation.