Cloning of genes involved in the antifungal activity of a fluorescent Pseudomonas sp.

The molecular basis of antifungal toxin production by a fluorescent Pseudom onas strain EM 85 was studied. The bacterial strain showed in vitro inhibit ion of growth of Rhizoctonia solani. NTG mutagenesis of the wild type strai n helped in the isolation of a antifungal-toxin-defective mutant AN 21. A g enomic library of the wild type strain was constructed in the cosmid vector pLAFR 1 and maintained in an E. coli background. Complementation analysis with cosmid library resulted in the isolation of a cosmid clone which compl emented the defective character in the mutant AN 21. The size of the comple menting DNA fragment was found to be 23.5 kb.