DNA- and PCR-fingerprinting in fungi

Abstract

DNA-fingerprinting has been successfully used to detect hypervariable, repetitive DNA sequences (minisatellites and microsatellites) in fungi. Combined with methods used to identify random amplified polymorphic DNA (RAPD), conventional DNA-fingerprinting hybridization probes can also be used as single primers to detect DNA polymorphisms among fungal species and strains. The oligonucleotides (CA)8, (CT)8, (CAC)5, (GTG)5, (GACA)4 and (GATA)4, as well as the phage M13 and its core sequence, have been used as specific probes in hybridization experiments and as primers for PCR analysis. Both methods have enabled the differentiation of all the fungal species and strains that were examined, including species of Penicillium, Trichoderma, Leptosphaeria, Saccharomyces, Candida and Cryptococcus. These methods have been used 1) to clarify the taxonomic relationships among relevant species of the Trichoderma aggregate, 2) to discriminate between aggressive and non-aggressive isolates of the rape seed phytopathogen, Leptosphaeria maculans, and 3) to identify strains of the pathogenic yeasts, Cryptococcus neoformans and Candida albicans. PCR-fingerprinting allowed serotypes of C. neoformans to be distinguished. The application of DNA- and PCR-fingerprinting to fungal DNA should aid in clarification of their taxonomy and improved diagnosis of mycotic disease.