Amplistroma Gen. Nov. and Its Relation to Wallrothiella, Two Genera with Globose Ascospores and Acrodontium-Like Anamorphs
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Mycologia, 101(6), 2009, pp. 904–919. DOI: 10.3852/08-213 # 2009 by The Mycological Society of America, Lawrence, KS 66044-8897 Amplistroma gen. nov. and its relation to Wallrothiella, two genera with globose ascospores and acrodontium-like anamorphs Sabine M. Huhndorf1 INTRODUCTION Botany Department, Field Museum of Natural History, Chicago, Illinois 60605-2496 Genus Wallrothiella Sacc. recently has been rede- scribed and the type species, W. congregata (Wallr.) Andrew N. Miller Sacc., was neotypified based on collections from Illinois Natural History Survey, University of Illinois at France and Ukraine (Re´blova´ and Seifert 2004). Urbana-Champaign, Champaign, Illinois 61820-6970 The genus is distinct in its globose, long-necked Matthew Greif ascomata, its wide, long, tapering paraphyses and its Botany Department, Field Museum of Natural History, cylindrical, stipitate asci with eight, small, globose Chicago, Illinois 60605-2496 ascospores. Surveys of wood-inhabiting Sordariomy- cetes in Puerto Rico and Great Smoky Mountains Gary J. Samuels National Park in the eastern United States uncovered USDA-ARS, Systematic Mycology & Microbiology several specimens that match the description of W. Laboratory, Room 304, B-011A, 10300 Baltimore Avenue, Beltsville, Maryland 20705-2350 congregata, and a collection from Puerto Rico was obtained in culture. A few years earlier several specimens that shared key characteristics of W. Abstract: Amplistroma is described as a new genus congregata were conveyed to us. These specimens for A. carolinianum, A. diminutisporum, A. guianense, have the same distinctive eight, globose-spored asci A. hallingii, A. ravum, A. tartareum and A. xylar- and wide paraphyses that are long and tapering above ioides.SpeciesofAmplistroma are distinguished by the asci. They differ however in having ascomata large stromata of textura intricata with polystichous united in large, fleshy stromata. To reveal the ascomata and long necks that are either erumpent relationships of W. congregata and these unknown from the stromatal surface or form bumps or fungi new sequences of the LSU were analyzed and protuberances. The type collection of Ceratostoma compared to known datasets with maximum parsimo- sphaerospermum was examined and found to be ny and Bayesian analyses. synonymous with Wallrothiella congregata. The distri- bution of W. congregata is expanded by collections MATERIALS AND METHODS from Costa Rica, the eastern United States and Taxon sampling.—Taxa sequenced in this study are listed Puerto Rico. Wallrothiella congregata has ascomata (TABLE I) with collection data provided under the exam- that are long-necked and develop individually or are ined specimens for each taxon. Representatives from gregarious on the substrate but do not form large families and orders within the Sordariomycetes were stromata. Amplistroma and Wallrothiella are distin- included to determine the phylogenetic position of the guished by small asci with eight, minute, globose target taxa. In addition we also included sequences for two ascospores. An acrodontium-like anamorph occurs in stromatic species, Pachytrype rimosa F.A. Ferna´ndez et al both genera. Phylogenetic analyses of 28S large- (COSTA RICA. Cartago, Parque Nacional Tapantı´, on 1 m subunit rDNA sequences group these taxa in a well diam log, 4-VII-2002, F.A. Ferna´ndez FF1066, F) and P. supported clade distinct from known orders within princeps (Penz. & Sacc.) M.E. Barr et al (USA. Hawaii. the Sordariomycetidae but showing unsupported Manuka Park, on dead wood of Metrosideros polymorpha 21- XI-1998, J.D. Rogers, F). All voucher specimens are relationships with the Chaetosphaeriales and the deposited in the Field Museum Mycology Herbarium (F). Magnaporthaceae. Family Amplistromataceae is de- Ascomata were mounted in water and replaced with scribed for this clade and placed within the lactophenol containing azure A. A minimum of 30 asci, Sordariomycetidae incertae sedis. ascospores and conidia were measured with Scion Image Key words: Amplistromataceae, Ascomycota, (www.scioncorp.com), and measurements were made and LSU rDNA, systematics, wood-inhabiting fungi images were captured of material in both mounting fluids. Ascomata were sectioned at 5 mm for light microscopy with the techniques of Huhndorf (1991). Images were captured with photomacrography, bright field (BF), phase contrast (PH) and differential interference microscopy (DIC), and Accepted for publication 5 May 2009. photographic plates were produced following the methods 1 Corresponding author. E-mail: [email protected] of Huhndorf and Ferna´ndez (1998). Methods for scanning 904 HUHNDORF ET AL: AMPLISTROMA GEN. NOV. 905 TABLE I. Taxa sequenced in this study Taxon Source GenBank accession number Amplistroma carolinianum Ascomata, Doi sn FJ532376 Amplistroma carolinianum Culture, BEO9923 FJ532377 Amplistroma guianense Ascomata, G.J.S. 5740 FJ532380 Amplistroma hallingii Ascomata, R.E. Halling 7389 FJ532379 Amplistroma ravum Ascomata, SMH4958 FJ532378 Pachytrype princeps Ascomata, Rogers sn FJ532382 Pachytrype rimosa Ascomata, FF1066 FJ532381 Wallrothiella congregata Ascomata, ANM81 FJ532374 Wallrothiella congregata Culture, SMH1760 FJ532375 electron microscopy (SEM) follow Meyer and Plaskowitz for the nucleotide substitution model and for priors with (1989). Cultures were obtained by germinating ascospores the chain temperature set at 0.2. The nucleotide substitu- on water agar or cornmeal dextrose agar. Germination tion model was chosen with Modeltest 3.7 (Posada and occurred at a high percentage after 48 h. Single ascospores Crandall 1998). Every 100th tree was sampled for 2 500 000 and asci with germinating spores were isolated with a generations. The first 6250 trees (25% of total) were micromanipulator or by hand. Growth observations of discarded as burn-in and posterior probabilities $95% were multispore isolates were made on cornmeal agar and malt determined from a consensus tree generated with the extract agar at 1 wk. Colors of the cultures follow Rayner remaining 18 750 trees. The consensus tree was viewed with (1970). The cultures are deposited at Centraalbureau voor PAUP 4.0 b10 (Swofford 2002). Schimmelcultures, Netherlands (CBS). DNA extraction, PCR amplification and sequencing.—De- RESULTS tailed protocols for the extraction, amplification and Sequence alignment and phylogenetic analyses.—The sequencing of DNA are described in Huhndorf et al (2008). LSU alignment contained a total of 87 taxa and 1046 Sequence alignment and phylogenetic analyses.—Methods for characters, 534 of which were constant and 404 were the alignment of LSU sequences are described in Huhndorf parsimony informative. The heuristic search pro- et al (2008). Sequence data for nine species were aligned duced 74 equally parsimonious trees (one of which with sequences of 78 species retrieved from GenBank, is shown in FIG. 1) with a consistency index of 0.315 representing major clades within the Sordariomycetes and a retention index of 0.654. where LSU data was available, using Se-Al 2.0a11 Carbon (Rambaut 2002). The data matrix was assembled with Se-Al, Species relationships.—The LSU phylogeny contains a then exported to Mesquite 1.12 (Madison and Madison clade representing the proposed new family support- 2006) where it was automatically aligned with Clustal 3 1.83 ed by both bootstrap support and significant Bayesian (Thompson et al 1997). The aligned matrix was imported posterior probability. These data support a strong clade back into Se-Al and edited manually. Scutellinia scutellata containing Wallrothiella congregata and the proposed DQ247806 was used as outgroup taxon. A maximum new genus. Another species, W, subiculosa, does not parsimony analysis was performed with PAUP 4.0 b10 (Swofford 2002). A heuristic search consisting of 100 cluster with W. congregata and is of uncertain placement random stepwise addition replicates was conducted with in these analyses. Ordinal placement of the new family is parsimony as the optimality criterion with gaps treated as not supported so it is referred to the Sordariomycetidae missing data. Tree-bisection-reconnection was chosen as the incertae sedis. Pachytrype rimosa and P. princeps find their branch-swapping algorithm with MULTREES option in effect. placement in the Diaporthales. Branch support was estimated by performing 1000 boot- strap replicates with a heuristic search consisting of 100 TAXONOMY random stepwise addition replicates for each bootstrap replicate with the above settings and the MAXTREES setting Amplistromataceae Huhndorf, A.N. Mill., M. Greif & set to 10 000 (Felsenstein 1985). The tree was viewed with Samuels, fam. nov. PAUP 4.0 b10 (Swofford 2002). A Bayesian analysis was MycoBank MB 513238 conducted with MrBayes 3.1.2 (Huelsenbeck et al 2001), Stromata superficialis, turbinata vel obovoidea vel irregu- which approximates posterior probabilities of clades with a lariter pulvinata, textura mollis vel cartilaginea; vel stromata Markov chain Monte Carlo (MCMC) method (Huelsenbeck nullus et perithecia seperata vel aggregata, subiculum and Ronquist 2001). The data matrix was analyzed with the hyphae vel nullus. Perithecia globosa vel subglobosa, general time reversible model of substitution including polysticha vel monosticha, longirostris. Paraphyses abun- estimation of invariant sites and assuming a discrete gamma dans. Asci abundans, cylindrici vel clavati. Ascosporae distribution (GTR + I + G) with six rate categories provided globosae. 906 MYCOLOGIA FIG. 1. Phylogenetic