Fumonisin B1-deficient mutants of Fusarium proliferatum

Genetical transformation of fumonisin-producing Fusarium proliferatum strain ITEM 1727 has been performed by restriction enzyme mediated integration technique leading to loss of fumonisin B1 (FB1) production. The synthetic green fluorescent protein gene has been successfully used as marker to select fungal genetically modified strains and screen them for fumonisin production. In a survey of 119 fluorescent transformants, cultured on yeast extract sucrose agar for 2 weeks, 20 transformants were found blocked in the FB1 production. Some of these FB1-deficient mutants produced an unidentified compound that may be related to a change in the fumonisin biosynthesis pathway. Replicate experiments confirmed the block of FB1 production in three transformants and the appearance of the new metabolite in two of them. The chemical structure of this compound needs to be established as well as its possible role in fumonisin biosynthesis. The availability of the FB1-deficient mutants identified in this study will allow to examine closely the molecular biology of Fusarium proliferatum in relation to fumonisins biosynthesis and to investigate the potential use of these mutants as competitive strains to control fungal pathogens producing fumonisins on maize and/or other important crops.