ITS primers for the identification of marketable Boletus.

Boletus species belonging to the section Boletus are the most frequently eaten fungi among those harvested in natural conditions in Europe. This section groups 10 taxa which are hardly distinguishable on the basis of their morphology. Some of them have been shown to induce allergic IgE-mediated symptoms either through inhalation, ingestion or contact. Since questions relating to the presence of allergens in any of the species most in demand (B. edulis, B. aereus, B. pinophilus, B. aestivalis, all classified as B. edulis s.l.) remain open, together with the absence of tools which distinguish the species, we sequenced the ITS region of 28 Boletus samples and then we designed specific primers. These allowed the effective separation of the taxa. In addition, the phylogenetic tree obtained from the sequences alignment revealed that B. violaceofuscus, a spectacular Chinese fungus considered belonging to the section Boletus and often sold intermixed with B. edulis s.l. specimens, clusters outside the section Boletus.