Genetic Diversity within an Italian Population of Forest Armillaria gallica Isolates as Assessed by RAPD-PCR Analysis

The genus Armillaria includes harmful fungal pathogens that cause root rot and wood decay in a broad range of host plants throughout the world. The aim of this study was to detect, by means of Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) markers, the level of intraspecific variability within isolates of an Armillaria gallica population sampled from a Quercus spp. stand located in Gravina in Puglia, southern Italy. UPGMA cluster analysis of RAPD profiles generated by decamer primers grouped the isolates in subclusters demonstrating relatively low intraspecific genetic variability. Moreover, RAPD pattern analysis yielded clusters which did not correspond to the groups discriminated by vegetative compatibility tests performed by a previous investigation on the same population. The findings of this research pose the question of whether somatic incompatibility, which involves an undefined number of genes and alleles per gene, might still be considered an effective tool for the epidemiological studies of A. gallica , whereas molecular analyses are more useful for assessing genomic variation within the species.