Genetic variation within Phaeoacremonium aleophilum and P. chlamydosporum in Italy

Genetic variation among isolates of Phaeoacremonium chlamydosporum (Pch) and P. aleophilum (Pal), two hyphomycetous fungi involved in the development of symptoms of esca and in a decline of young grapevines, was studied in eight Italian grapevine growing regions. Genetic variation was estimated by analysis of amplification profiles obtained in RAPD- and RAMS-PCR experiments (RAPD = Random Amplified Polymorphic DNA; RAMS = Random Amplified Micro- or Mini-Satellites). The genetic divergence between the two species suggests their assignment to two different genera. Within each species, a low level of polymorphism was found; however a higher degree of genetic variation was found with RAPD than with RAMS experiments, and more with Pal than with Pch isolates. No relationship was found for either species between the clustering of isolates in statistically defined groups and the geographic origin of those isolates. A low level of genetic disequilibrium was found in Pch and Pal, suggesting that sexual reproduction may occur in both fungi.