A bioluminescence assay for screening thermoregulated genes in a psychrotrophic bacterium Pseudomonas fluorescens
Résumé
Random transcription fusiondelivery, with bacterial luciferase genes as reporter, was performed in thepsychrotrophic bacterium Pseudomonas fluorescens. Direct screening on plates of theinsertions allowed the isolation of fusions into thermoregulated genes with good accuracy,either in a library of insertion fusions, or after genetic transfer of a putative regulatorymutation. Using this method, it was shown that in Ps. fluorescens, nearly 40% ofthe genes are thermoregulated and belong to at least three classes according to themaximal temperature of expression of the fused genes. This is more than had been estimatedby a previous method, and demonstrates the importance of thermoregulation inpsychrotrophic bacteria. As this reporter is the first to be used for direct screeningfor genes regulated by temperature, it should be of great value in the study ofmechanisms involved in adaptation to this environmental factor.