title: Cryptic species revealed by molecular phylogenetic analysis of sequences obtained from basidiomata of Tulasnella.
abstract: Delimitation of species and the search for a proper threshold for defining phylogenetic species in fungi are under discussion. In this study, morphological and molecular data are correlated to delimit species of Tulasnella, the most important mycobionts of Orchidaceae, which suffer from poor taxonomy. Resupinate basidiomata of Tulasnella species were collected in Ecuador and Germany, and 11 specimens (seven from Ecuador, four from Germany) were assigned to traditional species concepts by use of morphological keys. The specimens were compared by micro-anatomical examination with 75 specimens of Tulasnella borrowed from fungaria to obtain better insights on variation of characters. Sequences of the ITS region (127) were obtained after cloning from the fresh basidiomata and from pure cultures. Proportional variability of ITS sequences was analyzed within and among the cultures and the specimens designated to different morphospecies. Results suggested an intragenomic variation of less than 2%, an intraspecific variation of up to 4% and an interspecific divergence of more than 9% in Tulasnella. Cryptic species in Tulasnella, mostly from Ecuador, were revealed by phylogenetic analyses with 4% intraspecific divergence as a minimum threshold for delimiting species. Conventional diagnostic morphological characters appeared insufficient for species characterization. Arguments are presented for molecular delimitation of the established species Tulasnella albida, T. asymmetrica, T. eichleriana, T. cf. pinicola, T. tomaculum and T. violea.
authors.affiliation: Departamento de Ciencias Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto s/n C.P. 11 01 608, Loja, Ecuador djcruz@utpl.edu.ec.
authors.forename: Darío
authors.initials: D
authors.lastname: Cruz
authors.affiliation: Departamento de Ciencias Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto s/n C.P. 11 01 608, Loja, Ecuador.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Suárez
authors.affiliation: Departamento de Ciencias Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto s/n C.P. 11 01 608, Loja, EcuadorInstitute of Evolution and Ecology, Evolutionary Ecology of Plants, Eberhard-Karls-University Tübingen, Auf der Morgenstelle 1, D-72076 Tübingen, Germany.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Kottke
authors.affiliation: Institute of Ecology, Evolution and Diversity, Goethe-University Frankfurt am Main, Max-von-Laue-Str. 13, D-60438 Frankfurt am Main, Germany.
authors.forename: Meike
authors.initials: M
authors.lastname: Piepenbring
mesh_terms: D001483:Base Sequence; D001487:Basidiomycota / Q000235:genetics*; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D004484:Ecuador; D005858:Germany; D008969:Molecular Sequence Data; D029595:Orchidaceae / Q000382:microbiology*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013172:Spores, Fungal; D014197:Trees
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer
keywords: ITS-5.8S region; interspecific divergence; intragenomic variability; intraspecific variability; morphospecies; teleomorphic states