Characterization and Identification of <i>Strobilomyces confusus</i> Ectomycorrhizas on Momi Fir by RFLP Analysis of the PCR-Amplified ITS Region of the rDNA

Abstract

We identified ectomycorrhizal (ECM) roots formed by Strobilomyces confusus associated withAbies firma based on molecular analyses combined with ECM descriptions and examined the correspondence between above-groundS. confusus fruiting bodies and ECM roots below ground. Both mature fruiting bodies ofS. confusus and soil samples (1,000 cm3 in volume) from directly below the fruiting body were collected from three different spots in a 10 × 30-m plot in central Japan, in whichA. firma was the dominant species. Total of 6,156 root tips was collected from the area directly under the fruiting bodies ofS. confusus were classified representing 16 morphotypes. Among them, type 16 was identical in both the length of the internal transcribed spacer region and the restriction fragment length polymorphism profiles ofAlu I orHinf 1 digests, to those of the fruiting body ofS. confusus. Although a specific ECM association betweenS. confusus andA. firma was confirmed by using molecular tools, the abundance of the ECM roots was consistently low in every soil sample tested. These results suggest that even directly beneathS. confusus fruiting bodies, the occurrence of this species above-ground does not accurately reflect its relative abundance below ground, as evaluated in terms of the number of ECM roots.