LAUSR

ABSTRACT Tricholoma matsutake is an ectomycorrhizal fungus found in Pinaceae forests in Japan. It produces the “matsutake” mushroom, which has been consumed as an important part of Japanese cuisine since ancient times. Domestic matsutake are among the most valuable special forest products; however, their production in Japan has decreased over the past several decades. In the present study, to facilitate the conservation of genetic resources of domestic matsutake, we analyzed the fruiting bodies of T. matsutake collected from 13 prefectures, including one Picea glehnii forest and 12 Pinus densiflora forests in the Japanese archipelago, using SSR markers and elucidated their genetic structures . In total, 123 genotypes were detected in these populations. The genetic differentiation between populations was low (F ST = 0.048 and G’ST = 0.052). Moreover, no significant IBD was detected on the spatial scale, where the distance between the populations was up to approximately 1300 km. The genetic differences among T. matsutake populations in different regions of Japan are small. Three genetic clusters were identified, although no clear structure was confirmed based on geographical and genetic distributions However, F IS>0 was confirmed in several populations (p < 0.01), and AMOVA showed a significant genetic variation of approximately 5% among the groups, indicating a weak genetic structure of Japanese T. matsutake. The genetic resource conservation area could not be uniformly determined, because the correlation between genetic structure and geographical distribution is unclear.