Two New Endophytic Atractiellomycetes, Atractidochium Hillariae and Proceropycnis Hameedii
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Mycologia ISSN: 0027-5514 (Print) 1557-2536 (Online) Journal homepage: http://www.tandfonline.com/loi/umyc20 Two new endophytic Atractiellomycetes, Atractidochium hillariae and Proceropycnis hameedii M. Catherine Aime, Hector Urbina, Julian A. Liber, Gregory Bonito & Ryoko Oono To cite this article: M. Catherine Aime, Hector Urbina, Julian A. Liber, Gregory Bonito & Ryoko Oono (2018) Two new endophytic Atractiellomycetes, Atractidochium hillariae and Proceropycnis hameedii, Mycologia, 110:1, 136-146 To link to this article: https://doi.org/10.1080/00275514.2018.1446650 Published online: 04 Jun 2018. Submit your article to this journal View related articles View Crossmark data Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=umyc20 MYCOLOGIA 2018, VOL. 110, NO. 1, 136–146 https://doi.org/10.1080/00275514.2018.1446650 Two new endophytic Atractiellomycetes, Atractidochium hillariae and Proceropycnis hameedii M. Catherine Aime a, Hector Urbina a, Julian A. Liber b, Gregory Bonito b, and Ryoko Oono c aDepartment of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907; bDepartment of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824; cDepartment of Ecology, Evolution, and Marine Biology, University of California–Santa Barbara, Santa Barbara, California 93106 ABSTRACT ARTICLE HISTORY Sterile fungal isolates are often recovered in leaf and root endophytic studies, although these Received 12 July 2017 seldom play a significant role in downstream analyses. The authors sought to identify and Accepted 26 February 2018 — characterize two such endophytes one representing the most commonly recovered fungal KEYWORDS isolate in recent studies of needle endophytes of Pinus taeda and the other representing a rarely Atractiella; Helicogloeaceae; isolated root endophyte of Populus trichocarpa. Both are shown by DNA sequencing to be Hobsonia; Leucogloea; orchid undescribed species of Atractiellomycetes (Pucciniomycotina, Basidiomycota), a poorly character- mycorrhizae; Phleogena; ized class of mostly plant-associated and presumably saprobic microfungi. The authors describe Saccoblastia; 7 new taxa the new genus and species Atractidochium hillariae (Phleogenaceae) and the new species Proceropycnis hameedii (Hoehnelomycetaceae), both in the Atractiellales, to accommodate these unusual isolates. Following incubations of 1–2 mo, A. hillariae produces minute white sporodo- chia, similar to those produced by several other members of Atractiellales, whereas Pr. hameedii forms conidia singly or in chains in a manner similar to its sister species Pr. pinicola. Additionally, we provide a taxonomic revision of Atractiellomycetes based on multilocus analyses and propose the new genera Neogloea (Helicogloeaceae) and Bourdotigloea (Phleogenaceae) to accommodate ex-Helicogloea species that are not congeneric with the type H. lagerheimii. Atractiellomycetes consists of a single order, Atractiellales, and three families, Hoehnelomycetaceae, Phleogenaceae, and Helicogloeaceae. Accumulated evidence suggests that Atractiellomycetes species are com- mon but infrequently isolated members of plant foliar and root endobiomes. INTRODUCTION unlikely endophytic role for these (Toome et al. 2014). Most recovered foliar fungal endophytes are species of Known root associates in Pucciniomycotina are like- Ascomycota, with members of the Sordariomycetes, wise sparsely reported and primarily consist of the root Dothideomycetes, Leotiomycetes, and Eurotiomycetes pathogen Helicobasidium (Valder 1958), unnamed being predominant (e.g., Arnold and Lutzoni 2007; orchid-mycorrhiza formers in Atractiellales (Kottke Arnold et al. 2007). Although fungal species from the et al. 2010), and the Populus root associate Atractiella Basidiomycota can also be common in the endophyte rhizophila (Bonito et al. 2017). biome, especially in woody tree trunks (e.g., Crozier Atractiellomycetes constitute one of nine classes of et al. 2006; Thomas et al. 2008; Vega et al. 2010), few Pucciniomycotina (Aime et al. 2006, 2014;Schelletal. are reported abundantly or consistently in leaves or in 2011). Species are primarily known for forming inconspic- association with a specific plant host (but see Pinruan uous basidiomata or conidiomata on woody or herbaceous et al. 2010). Within Pucciniomycotina (one of three material, where they are assumed saprobic (Bauer et al. subphyla of Basidiomycota), only some yeast species 2006). However, recent studies, spurred by environmental in the genera Rhodotorula and Sporobolomyces appear sequencing or molecular identifications of nonsporulating to have been infrequently recovered as foliar endo- cultures, show that members of the class may be associated phytes (Bura et al. 2012; Urbina and Aime 2018; Zhao with plant roots and are presumably mycorrhizal or endor- et al. 2002), although environmental sequences indica- hizal (Kottke et al. 2010;Bonitoetal.2016, 2017). tive of Mixia (Mixiomycetes) were detected from leaves The most frequently cultured fungus (30.7% of iso- in Europe and Asia, which may suggest a potential but lates) from a recent study of Pinus taeda (loblolly pine) CONTACT M. Catherine Aime [email protected] Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/umyc. Seven new taxa reported: Atractidochium, gen. nov.; Atractidiochium hilleriae, sp. nov.; Proceropycnis hameedii, sp. nov.; Bourdotigloea, gen. nov.; Neogloea, gen. nov.; Neogloea variabilis, comb. nov.; Bourdotigloea vestita, comb. nov. © 2018 The Mycological Society of America Published online 04 Jun 2018 MYCOLOGIA 137 needle endophytes belonged to a single unknown, ster- USA), Difco potato dextrose agar (PDA), Difco yeast ile operational taxonomic unit (Oono et al. 2015). DNA extract-peptone-dextrose (YPD) agar, and walnut agar sequence analyses indicated a basidiomycetous affinity (WA; 8 whole blended walnuts with shells in 500 mL of for this species, with possible placement in the Millipore water and 1.5% of agar, autoclaved at 121 C Atractiellomycetes. Additionally, during ongoing efforts and 15 psi for 20 min). Cultures were incubated at room to document endorhizal associates of Populus tricho- temperature and examined every 2 wk for 2 mo for signs carpa, a single (from >1800 isolations) sterile strain of of differentiated hyphae or sporulating structures. what appeared to be an Atractiellomycete, but one not Cultures were photographed with a SZ61-Olympus dis- congeneric with the more frequently isolated and secting microscope with SC30-Olympus camera and the recently described A. rhizophila, was discovered software cellSens Olympus 1.14 (Olympus Life Science (Bonito et al. 2016, 2017). The goals of the present Solutions, Waltham, Massachusetts, USA). Water study are to completely characterize these inhabitants mounts were examined with a BH2-Olympus research of Pi. taeda needles and Po. trichocarpa roots, described microscope and photographed with the same camera. To here as Atractidochium hillariae, gen. et sp. nov., and ascertain the nuclear status of Pr. hameedii, slide cultures Proceropycnis hameedii, sp. nov., respectively. To this were prepared and visualized following the methods of end, a resolved multilocus phylogenetic analysis of the Fisher et al. (2018) by growing mycelium across a thin Atractiellomycetes is presented and the genera Neogloea layer of nutrient agar, made by dipping sterile glass gen. nov. and Bourdotigloea gen. nov., are proposed to microscope slides into liquid medium (10 g/L malt accommodate some species of Helicogloea that are not extract, 1 g/L yeast extract, 10 g/L Bacto agar; BD congeneric with the type, H. lagerheimii. Biosciences, San Jose, California, USA) and allowing this to solidify. Plugs with mycelium measuring 0.5 cm MATERIALS AND METHODS × 1 cm were placed on one side of the slide, then slides were placed in a moist chamber, prepared in glass Petri Strain isolation and morphological characterization.— dish with a wet, sterile wipe and bent glass rod to elevate Cultures from needles of adult Pi. taeda trees were the slide. After 1 wk of growth, plugs were removed from isolated from surface sterilized mature needles (second the slides with a razor. Fungal cell walls and nuclei were year) in the Blackwood Forest Division of Duke Forest in stained following a protocol adapted from Robin et al. Orange County, North Carolina, USA (approx. 35.97°N, (1986) and Chazotte (2011). Briefly, slides with growing 79.09°W). Cultures were prevalent in needles collected mycelium were submerged for 15 min in phosphate- during both winter and summer months and were buffered saline (PBS) solution with bovine serum albu- isolated over multiple years (Arnold et al. 2007; Oono min (BSA) (PBS+; 137 mM NaCl, 2.7 mM KCl, 10 mM et al. 2015); details of isolation and culturing are outlined Na2HPO4, 1.8 mM KH2PO4, 1 mM CaCl2, 0.5 mM in Oono et al. (2015). From roots of natural Po. MgCl2, 1mg/mL BSA). Then slides were placed in 0.2% trichocarpa stands in southern Washington, an isolate of Triton X-100 for 5 min, then for 10 min in PBS+ without Atractiellomycetes (PMI 927; GenBank accession number BSA. The mycelium on the slides was inundated in 50 μL KF428609; Bonito et al. 2016, supplementary material) of 10 μg/mL fluorescein-labeled wheat germ agglutinin λ λ was obtained among ca. 1800 fungal isolates as part of ( ex ~ 494 nm, em ~ 518 nm) and placed in a humid the Plant Microbial Interfaces