title: Ultrastructural and molecular analyses of Rhizophydiales (Chytridiomycota) isolates from North America and Argentina.
abstract: The Rhizophydiales is the most recently circumscribed order in the Chytridiomycota. Past studies focused on soil chytrids from North America and Australia to determine the range of diversity within this clade of chytrids and established three families (Rhizophydiaceae, Terramycetaceae, and Kappamycetaceae) in the new order. Although Rhizophydiales contains seemingly simple chytrids morphologically, analyses of ribosomal gene sequences and zoospore characters have demonstrated unexpected genetic and ultrastructural diversity, highlighting the need for broader habitat and geographic sampling to reveal the actual diversity within this new order. To enlarge our sampling, in this study we investigated 38 newly cultured chytrids collected from aquatic habitats in Argentina, a territory under-explored for chytrid diversity. From analyses of thallus morphology, zoospore ultrastructure, and 28S and ITS1-5.8S-ITS2 ribosomal gene sequences, we expand the concept of Rhizophydiales, describing seven new families (Alphamycetaceae, Angulomycetaceae, Aquamycetaceae, Globomycetaceae, Gorgonomycetaceae, Pateramycetaceae, and Protrudomycetaceae) and eight new genera (Alphamyces, Angulomyces, Aquamyces, Globomyces, Urceomyces, Gorgonomyces, Pateramyces, and Protrudomyces). Results of this study underscore that even more extensive sampling from varied habitats and geographies is needed to adequately ascertain the diversity of chytrids in the Rhizophydiales.
authors.affiliation: Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA. letch006@bama.ua.edu <letch006@bama.ua.edu>
authors.forename: Peter M
authors.initials: PM
authors.lastname: Letcher
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Vélez
authors.forename: María Eugenia
authors.initials: ME
authors.lastname: Barrantes
authors.forename: Martha J
authors.initials: MJ
authors.lastname: Powell
authors.forename: Perry F
authors.initials: PF
authors.lastname: Churchill
authors.forename: William S
authors.initials: WS
authors.lastname: Wakefield
mesh_terms: D001118:Argentina; D008411:Chytridiomycota / Q000235:genetics* / Q000302:isolation & purification / Q000648:ultrastructure*; D004271:DNA, Fungal / Q000145:classification* / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D005843:Geography; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009656:North America; D010802:Phylogeny; D012339:RNA, Ribosomal, 28S / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D012339:RNA, Ribosomal, 28S