MOLECULAR POLYMORPHISM AND PHENOTYPIC VARIATION IN ASPERGILLUS-CARBONARIUS

Thirteen collection strains and field isolates of Aspergillus carbonar ius were examined by using various genotypic and phenotypic approaches . Restriction fragment length polymorphism analysis of the ribosomal R NA gene cluster and the mitochondrial DNA of the strains revealed only slight variations, except for one field isolate (IN7), which exhibite d completely different ribosomal RNA gene cluster and mitochondrial DN A patterns. The mitochondrial DNAs of these strains were found to be m uch larger (45 to 57 kb) than those found earlier in the A. niger aggr egate. Strain-specific characters could be detected by the random ampl ified polymorphic DNA technique. Isoenzyme analysis and examination of carbon source utilisation patterns of the strains also revealed some intraspecific variability, though much smaller than that observed by u sing DNA-based techniques. The dendrograms constructed based on genoty pic and phenotypic data suggest that strain IN7 might represent a new subspecies of A. carbonarius.