Oral insecticidal activity of root colonizing P. fluorescens CHA0: a biocontrol agentwith potential to control plant pests and diseases?

Abstract: The application of microbial biocontrol agents for the control of fungal plant diseasesand plant insect pests is a promising approach in the development of environmentally benign pestmanagement strategies. The ideal biocontrol organism would be a bacterium or a fungus withactivity against both, insect pests and fungal pathogens. Here we demonstrate the oral insecticidalactivity of the root colonizing Pseudomonas fluorescens CHA0, which is so far known for itscapacity to efficiently suppress fungal plant pathogens. Feeding assays with CHA0-sprayed leavesshowed that this strain displays oral insecticidal activity and is able to efficiently kill larvae of threeimportant insect pests. We further show data indicating that the Fit insect toxin produced by CHA0and also metabolites controlled by the global regulator GacA contribute to oral insect toxicity.