A cold-active antifungal Pseudomonas fluorescens isolate from Greenland

Abstract: Potato soils from South Greenland contain a number of fungal-inhibiting bacteria. Oneisolate, Pseudomonas fluorescens strain In5, shows high inhibition of several plant-pathogenicfungi e.g. Rhizoctonia solani, Pythium aphanidermatum, Fusarium graminearum andPhytophthora infestans in in vitro inhibition assays. Also in a microcosm assay strain In5 showedthe ability to suppress R. solani. By the use of different biochemical and genetical methods, strainIn5 was found to contain the capacity to produce the antifungal compounds hydrogen cyanide(HCN) and non-ribosomal peptide (NRP). Random mutagenesis with a Tn5 derived transposonresulted in one mutant deficient in HCN production and two mutants with reduced antifungalactivities.