Mitochondrial DNA analysis of Phialophora verrucosa

Restriction fragment length polymorphism (RFLP) of mitochondrial DNA (mtDNA) was examined in 32 isolates of Phialophora verrucosa (eight isolates from Japan, 10 from China, four from the USA, six from Venezuela and four from Colombia) and in three of Phialophora americana using five restriction enzymes. P. verrucosa isolates were divided into 10 mtDNA types based on RFLP patterns. Phylogeny constructed on sequence divergence of mtDNA indicated that P. verrucosa is a single species and isolates are clustered into three groups. Japan and the USA contained Group A and Group B isolates, China Group B isolates and South America Group B and Group C isolates. RFLP patterns of P. americana mtDNA were identical to those of Type 1 or Type 4 of P. verrucosa mtDNA, suggesting that both are identical. RFLP patterns of P. verrucosa were distinct from those of other dematiaceous fungi including Exophiala jeanselmei, E. moniliae, E. dermatitidis, E. spinifera, Cladophialophora (Cladosporium) carrionii, Fonsecaea pedrosoi, and Hortaea werneckii. These results indicate that RFLP analysis of mtDNA is a useful method for the identification, taxonomy, typing, epidemiology and phylogeny of P. verrucosa.