Genetic variability of ITS sequence among Pisolithus strains associated with native hosts and exotic Eucalyptus in the Mediterranean forests.

ANTA, BERTA¹, JESúS DíEZ² & J.L. MANJóN².

¹Viveros Alborada, Cañada 28, 28597 Fuentidueña de Tajo, SPAIN. ²Biología Vegetal, Universidad de Alcalá, 28871 Alcalá de Henares, SPAIN.

Pisolithus tinctorius is a common mycorrhizal fungus in the indigenous forests (Quercus ilex, Pinus spp.) and shrublands (Cistus spp., etc.) of the Mediterranean Basin. In this region, it also establishes mycorrhizal symbiosis with Pinus and Eucalyptus in forest plantations. In order to know whether Pisolithus populations of exotic plantations are native, or have been introduced with the Eucalyptus trees and introgression of exotic strains in the indigenous populations is happening, we have sequenced the ITS (nuclear rDNA) of 20 isolates of P. tinctorius associated with indigenous hosts or exotic Eucalyptus species. To take into account a general overview ot the world variability in the ITS of this fungus, the present study also includes the ITS sequence of several strains from other continents (Africa, America, Australia).