SECONDARY METABOLITE PRODUCTION IN FILAMENTOUS FUNGI DISPLAYED

We report the potential of differential display technology for the iso lation of genes of biotechnological interest. We have assessed the use fulness of the technique for the cloning of genes involved in the prod uction of secondary metabolites, many of which are of industrial use o r interest. We have used the complex pathway for the biosynthesis of g ibberellins, as well as bikaverin and carotenoids, present in the fila mentous fungus Gibberella fujikuroi as a test system. From a total dis play of approximately 16000 PCR products for each RNA sample, 100 were derived from the derepressed but not the repressed condition. These p roducts were analysed by Northern blotting and a subset of 16 such PCR products showed differential expression at the transcript level. A nu mber of different mRNA species were observed on this basis which varie d in their size. Hence, this approach appears suitable for the isolati on of genes involved in the complex pathways often required for the sy nthesis of secondary metabolites in organisms which are genetically in tractable. Moreover, the method has the advantage that it is quick, di fferential displays being obtained after 2 days and DNA clones in 6 da ys.