title: High diversity and widespread occurrence of mitotic spore mats in ectomycorrhizal Pezizales.
abstract: Fungal mitospores may function as dispersal units and/ or spermatia and thus play a role in distribution and/or mating of species that produce them. Mitospore production in ectomycorrhizal (EcM) Pezizales is rarely reported, but here we document mitospore production by a high diversity of EcM Pezizales on three continents, in both hemispheres. We sequenced the internal transcribed spacer (ITS) and partial large subunit (LSU) nuclear rDNA from 292 spore mats (visible mitospore clumps) collected in Argentina, Chile, China, Mexico and the USA between 2009 and 2012. We collated spore mat ITS sequences with 105 fruit body and 47 EcM root sequences to generate operational taxonomic units (OTUs). Phylogenetic inferences were made through analyses of both molecular data sets. A total of 48 OTUs from spore mats represented six independent EcM Pezizales lineages and included truffles and cup fungi. Three clades of seven OTUs have no known meiospore stage. Mitospores failed to germinate on sterile media, or form ectomycorrhizas on Quercus, Pinus and Populus seedlings, consistent with a hypothesized role of spermatia. The broad geographic range, high frequency and phylogenetic diversity of spore mats produced by EcM Pezizales suggests that a mitospore stage is important for many species in this group in terms of mating, reproduction and/or dispersal.
authors.affiliation: Department of Plant Biology, University of Minnesota, St. Paul, MN 55108, USA. healy089@umn.edu
authors.forename: R A
authors.initials: RA
authors.lastname: Healy
authors.forename: M E
authors.initials: ME
authors.lastname: Smith
authors.forename: G M
authors.initials: GM
authors.lastname: Bonito
authors.forename: D H
authors.initials: DH
authors.lastname: Pfister
authors.forename: Z-W
authors.initials: ZW
authors.lastname: Ge
authors.forename: G G
authors.initials: GG
authors.lastname: Guevara
authors.forename: G
authors.initials: G
authors.lastname: Williams
authors.forename: K
authors.initials: K
authors.lastname: Stafford
authors.forename: L
authors.initials: L
authors.lastname: Kumar
authors.forename: T
authors.initials: T
authors.lastname: Lee
authors.forename: C
authors.initials: C
authors.lastname: Hobart
authors.forename: J
authors.initials: J
authors.lastname: Trappe
authors.forename: R
authors.initials: R
authors.lastname: Vilgalys
authors.forename: D J
authors.initials: DJ
authors.lastname: McLaughlin
mesh_terms: D001203:Ascomycota / Q000145:classification* / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D016013:Likelihood Functions; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000145:classification* / Q000235:genetics; D010802:Phylogeny; D028223:Pinus / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D032107:Populus / Q000382:microbiology; D029963:Quercus / Q000382:microbiology; D017422:Sequence Analysis, DNA; D013172:Spores, Fungal / Q000145:classification / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer