title: Archaeorhizomyces borealis sp. nov. and a sequence-based classification of related soil fungal species.
abstract: The class Archaeorhizomycetes (Taphrinomycotina, Ascomycota) was introduced to accommodate an ancient lineage of soil-inhabiting fungi found in association with plant roots. Based on environmental sequencing data Archaeorhizomycetes may comprise a significant proportion of the total fungal community in soils. Yet the only species described and cultivated in this class is Archaeorhizomyces finlayi. In this paper, we describe a second species from a pure culture, Archaeorhizomyces borealis NS99-600(T) (=CBS138755(ExT)) based on morphological, physiological, and multi-locus molecular characterization. Archaeorhizomyces borealis was isolated from a root tip of a Pinus sylvestris seedling grown in a forest nursery in Lithuania. Analysis of Archaeorhizomycete species from environmental samples shows that it has a Eurasian distribution and is the most commonly observed species. Archaeorhizomyces borealis shows slow growth in culture and forms yellowish creamy colonies, characteristics that distinguish A. borealis from its closest relative A. finlayi. Here we also propose a sequence-based taxonomic classification of Archaeorhizomycetes and predict that approximately 500 species in this class remain to be isolated and described.
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden. Electronic address: audrius.menkis@slu.se.
authors.forename: Audrius
authors.initials: A
authors.lastname: Menkis
authors.affiliation: Department of Evolutionary Biology, Uppsala University, Norbyvägen 18D, SE-75236 Uppsala, Sweden.
authors.forename: Hector
authors.initials: H
authors.lastname: Urbina
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Timothy Y
authors.initials: TY
authors.lastname: James
authors.affiliation: Department of Evolutionary Biology, Uppsala University, Norbyvägen 18D, SE-75236 Uppsala, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Rosling
mesh_terms: D001203:Ascomycota / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004271:DNA, Fungal / Q000235:genetics; D010802:Phylogeny; D041605:Pinus sylvestris / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D012339:RNA, Ribosomal, 28S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
chemical_list: D004271:DNA, Fungal; D012339:RNA, Ribosomal, 28S
keywords: Plant roots; Rhizosphere; Soil clone group 1; Soil fungi; Symbiosis