title: Evolutionary history of the sequestrate genusRossbeevera(Boletaceae) reveals a new genusTurmalineaand highlights the utility of ITS minisatellite-like insertions for molecular identification.
abstract: The sequestrate (truffle-like) basidiomycete generaRossbeevera,Chamonixia, andOctavianiaare closely related to the epigeous mushroom generaLeccinumandLeccinellum. In order to elucidate the properties and placement of several undescribed sequestrate taxa in the group and to reveal the evolutionary history ofRossbeeveraand its allies, we conducted phylogenetic analyses based on three nuclear (ITS, nLSU,EF-1α) and two mitochondrial DNA loci (ATP6and mtSSU) as well as precise morphological observations. Phylogenetic analyses of three nuclear loci suggest a complex evolutionary history with sequestrate fruiting bodies present in several clades, including a previously unrecognized sister clade toRossbeevera. Here we propose a new sequestrate genus,Turmalinea, with four new species and one new subspecies as well as two new species ofRossbeevera. The three-locus nuclear phylogeny resolves species-level divergence within theRossbeevera-Turmalinealineage, whereas a separate phylogeny based on two mitochondrial genes corresponds to geographic distance within each species-level lineage and suggests incomplete lineage sorting (ILS) and gene introgression within several intraspecific lineages ofRossbeevera. Furthermore, topological incongruence among the three nuclear single-locus phylogenies suggests that ancient speciation withinRossbeeveraprobably involved considerable ILS. We also found an unusually long, minisatellite-like insertion within the ITS2 in allRossbeeveraandTurmalineaspecies. A barcode gap analysis demonstrates that the insertion is more informative for discrimination at various taxonomic levels than the rest of the ITS region and could therefore serve as a unique molecular barcode for these genera.
authors.affiliation: Kanagawa Prefectural Museum of Natural History, 499 Iryuda, Odawara-shi, Kanagawa 250-0031, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Orihara
authors.affiliation: National Herbarium of Victoria, Royal Botanic Gardens Melbourne, Private Bag 2000, Birdwood Ave, South Yarra, Vic., 3141, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Lebel
authors.affiliation: Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
authors.forename: Z-W
authors.initials: ZW
authors.lastname: Ge
authors.affiliation: Department of Plant Pathology, University of Florida, Gainesville FL 32611-0680, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Smith
authors.affiliation: Fungus/Mushroom Resource and Research Center, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Maekawa
keywords: DNA barcoding; biogeography; cryptic species; hypogeous fungi; introgression; species tree