Phylogenetic relationship and species delimitation of matsutake and allied species based on multilocus phylogeny and haplotype analyses.

Tricholoma matsutake (S. Ito & S. Imai) Singer and its allied species are referred to as matsutake worldwide and are the most economically important edible mushrooms in Japan. They are widely distributed in the northern hemisphere and established an ectomycorrhizal relationship with conifer and broadleaf trees. To clarify relationships among T. matsutake and its allies, and to delimit phylogenetic species, we analyzed multilocus datasets (ITS, megB1, tef, gpd) with samples that were correctly identified based on morphological characteristics. Phylogenetic analyses clearly identified four major groups: matsutake, T. bakamatsutake, T. fulvocastaneum and T. caligatum; the latter three species were outside the matsutake group. The haplotype analyses and median-joining haplotype network analyses showed that the matsutake group included four closely related but clearly distinct taxa (T. matsutake, T. anatolicum, Tricholoma sp. from Mexico and T. magnivelare) from different geographical regions; these were considered to be distinct phylogenetic species.