Genetic diversity of Heterobasidion, the causal agent of conifer root and butt rot

Heterobasidion annosum s.l. is a root and butt rot fungus that cause losses in timber production. This pathogen is relatively common and can be found in saprophytic habit on stumps and wood logs in the forest (Woodward et al., 1998). In Italy, within the complex H. annosum s.l., three European species (H. annosum s.s., H. abietinum and H. parviporum) have been described (Capretti et al., 1998). Furthermore also the invasive H. irregulare, introduced from North America, was found along the Tyrrhenian coast (D’Amico et al., 2007; Gonthier at al., 2014). By using molecular markers the diversity of H. annosum s.l. populations have been studied in Italy (Petta et al., 2001; D’Amico et al., 2007; Zamponi et al., 2007). Genetic divergences in H. annosum and H. abietinum populations were found (Zamponi et al., 2007; Luchi et al., 2011). These variations within each fungal population, could be mainly related to the host population but also to the morphology of Italian peninsula that reduced the gene migration among fungal strains. Objective of this work is to study the population structure and spatialization of genetic diversity in H. abietinum and H. annosum populations in Italy by using minisatellites.