Gluconic acid: An antifungal agent produced by Pseudomonas species in biological control of take-all

Pseudomonas strain AN5 produces d-gluconic acid which acts as an antifungal agent in suppressing the take-all fungal pathogen, both on potato dextrose media and in the wheat rhizosphere. Transposon mutants which have lost biocontrol do not produce gluconic acid, but restoration of gluconic acid production by complementation restores take-all biocontrol.