Estimation of novel colony establishment and persistence of the ectomycorrhizal basidiomycete Tricholoma matsutake in a Pinus densiflora forest

Tricholoma matsutake is an economically valuable fungus in Japan. Its fruit bodies occur in colonies established in natural pine forests. We traced colony establishment processes of T. matsutake in 2001 and 2010 by using microsatellite markers. T. matsutake genets persisted at least for a decade. Comparing colonies found in 2001 and 2010, five novel colonies were observed in 2010, where the organic layer was removed or pine trees were regenerated less than 50 y ago. The novel colonies were genotyped, and all of them were different from colonies found in 2001, indicating that these colonies were established by dispersed basidiospores. Novel genet and candidate parent genets were located in the same ridge, and the mean geographical distance between a novel genet and a parent genet was 19.59 ± 14.73 m, indicating that basidiospores may colonize more easily on roots of hosts near parental basidiocarps. In conclusion, sufficient basidiospore supply and organic layer removal or pine tree regeneration were essential factors for colony establishment of T. matsutake.