Population Evidence of Cryptic Species and Geographical Structure in the Cosmopolitan Ectomycorrhizal Fungus, Tricholoma scalpturatum

• Published in: Microbial ecology Vol. 56; no. 3; pp. 513 - 524
• Main Authors: Carriconde, Fabian, Gardes, Monique, Jargeat, Patricia, Heilmann-Clausen, Jacob, Mouhamadou, Bello, Gryta, Hervé
• Format: Journal Article
• Language: English
• Published: New York New York : Springer-Verlag 01.10.2008; Springer Science + Business Media, Inc; Springer-Verlag; Springer; Springer Nature B.V; Springer Verlag
• Subjects: Agaricales - genetics; Agaricales - growth & development; Base Sequence; Biodiversity; Biological and medical sciences; Biological taxonomies; Biomedical and Life Sciences; Cluster Analysis; Cryptic species; DNA, Fungal - chemistry; DNA, Fungal - genetics; DNA, Ribosomal Spacer - chemistry; DNA, Ribosomal Spacer - genetics; Ecology; Ecology, environment; Endemism; Europe; Evolutionary genetics; Fundamental and applied biological sciences. Psychology; Fungal fruiting bodies; Fungi; Genetic diversity; Genetic structure; Genetic Variation; Geoecology/Natural Processes; Human genetics; Life Sciences; Microbial Ecology; Microbiology; Microsatellite Repeats - genetics; Molecular Sequence Data; Mycology; Nature Conservation; Original Article; Phylogeny; Polymerase Chain Reaction; Polymorphism, Genetic; Polymorphism, Restriction Fragment Length; Population differentiation; Population genetics; Population structure; Tricholoma; Vegetal Biology; Water Quality/Water Pollution; Southern Europe; Scandinavia; Europe; Spain; Western Europe; Ectomycorrhizal Fungus; Cryptic Species; Genetic Group; Internal Transcribe Spacer; Saprotrophic Fungus; Ability; Root; Sexual behavior; Ribosomal DNA; Environmental factor; Genotype; Genetic diversity; Method; Tricholoma; Biodiversity; Population genetics; Breeding behavior; Basidiomycota; Cryptic; Fungi; Restriction fragment length polymorphism; Microsatellite DNA; Ecosystem; Habitat
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-008-9370-2

Tricholoma scalpturatum is an ectomycorrhizal fungus that forms symbioses with roots of diverse trees and shrubs. It is commonly encountered in a wide range of habitats, across temperate ecosystems. A previous study has revealed a high genetic diversity at a local scale, and ruderal abilities. To examine genetic structure at a large geographical scale, a total of 164 basidiocarps were collected from 30 populations located in Western Europe, from Spain to Scandinavia. These samples were analyzed by three molecular methods with different levels of resolution: inter-simple sequence repeats (ISSRs), restriction fragment length polymorphisms (RFLPs) in the rDNA internal transcribed spacer (ITS), and ITS sequence analysis. Considerable genetic variation was found, and the morphospecies was separated into two genetic groups that were distinct from each other. The ISSR data and the relatively low percentage value (96%) of shared sequence polymorphisms in the ITS between isolates from the two groups, strongly suggest cryptic species and long-lasting separation. No geographical exclusion was detected for these two widely distributed taxa. However, high estimates of population differentiation were observed in each group, including between populations less than a few kilometers apart. This result provides evidence for limited gene flow and/or founding effects. It also indicates that T. scalpturatum does not constitute a random mating population, and the hypothesis of endemism cannot be excluded for this cosmopolitan wind-dispersed fungus.