Spatial distribution of the subterranean mycelia and ectomycorrhizae of Suillus grevillei genets

To analyze the distribution of subterranean parts of ectomycorrhizal genets, species-specific polymorphic markers are necessary. In this study, we examined the species-specificity of five polymorphic simple sequence repeat (SSR) markers of Suillus grevillei, and found that one, SG-5, is species-specific to S.grevillei and polymorphic. Using the SG-5 marker, we analyzed for the first time the horizontal and vertical distribution of the subterranean parts of several S.grevillei genets. The spatial distribution of S.grevillei genets in the soil demonstrated that the develop ment of S.grevillei sporocarps is correlated with that of extra-radical mycelia and ectomycorrhizae of the same genet, which are distributed in a narrow area. However, sporocarps are not always centered over the subterranean parts and the amount of subterranean mycelia and mycorrhizae is not always correlated to the number of sporocarps formed on them. No S.grevillei mycelia and mycorrhizae were detected beneath the positions where S.grevillei sporocarps emerged in the previous year. The observation indicates the rapid alteration of the subterranean parts of S.grevillei genets, and suggests that S.grevillei genets change location rather than merely extend their habitat year after year.