Ectomycorrhizal fungal communities in an Abies firma forest, with special reference to ectomycorrhizal associations between seedlings and mature trees

Ectomycorrhizal fungal communities of both seedlings and mature trees of Abies firma Sieb. et Zucc. were studied based on morphological and molecular analyses of ectomycorrhizal (ECM) roots. A total of 142 seedlings and 28 soil cores were collected from a 10 m x 30 m plot, and 37 morphotypes were recorded from seedlings and 23 from mature trees. A morphotype, type 21, formed by an unidentified fungus that is likely a Russula species, was dominant on both seedlings (30% of the total number of the ECM roots detected) and mature trees (56%) and overlapped them spatially, suggesting a hyphal linkage between mature trees and seedlings in the plot. A total of 12 morphotypes were recorded from soil blocks underneath fruiting bodies of undescribed Russula sp. 1, the dominant aboveground fruiting body in the plot, among which type 21 was the most abundant. The pattern of restriction fragment length polymorphism of this type was identical to that of the fruiting body of Russula sp. 1. These results indicate that Russula sp. 1 was the dominant ECM fungus associated with both mature trees and seedlings and would play an important role in the dynamics and maintenance of this Abies-dominated forest site.