Luciferase genes as a marker for Pseudomonas corrugata

Pseudomonas corrugata, causal agent of tomato pith necrosis, was modified with the lux operon of Vibrio fischeri. Transposon Tn4431 was used to introduce the lux operon into the chromosome of P. corrugata strain 4.3t. Light, emitted by bioluminescent mutants, was detected with photometry and autoradiography. One bioluminescent mutant, designated strain 4.3t lux18, expressed high levels of light in vitro and in vivo. This strain was identical to its wild-type parent in all aspects studied, including colony morphology, pathogenicity, and growth in vitro and in planta. Bacterial growth in symptomatic and asymptomatic tissues was monitored and visualized by bioluminescence. The results indicate that bioluminescence is a good genetic marker system for investigating the epidemiology and population dynamics of P. corrugata.