Genetic diversity and interrelationships among common European Suillus species based on ribosomal DNA sequences

The nucleotide sequence of the internal transcribed spacer (ITS) 1 and 2 re gions was determined for 22 Suillus isolates representing seven species. An alysis of the sequence data along with 12 related sequences from databases divided the 34 isolates into seven groups, and six of these were supported by 100% bootstrap values. Isolates belonging to Suillus granulatus (0-11 di vergence) were divided into three groups (SG1, SG2 and SG3); SG1 and SG2 ha d 100% bootstrap values. SG2 was clustered with two Suillus collinitus isol ates and a Suillus variegatus isolate; SG3 was linked to a previously chara cterised Suillus subluteus isolate. These results clearly indicate heteroge neity among the isolates described under these species. Intra- (0.4-11) and inter- (2.4-13.6) specific divergence varied considerably. Suillus laricin us showed a high level (0.5-4.4) of intra-specific divergence. Suillus bovi nus showed maximum divergence (11.4-13.3) to all other species examined. Th e potential of the ITS region for understanding the intra- and inter-specif ic relationships among Suillus species and refining their taxonomy is discu ssed. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.