Mycologia, 102(3), 2010, pp. 574–587. DOI: 10.3852/09-051 # 2010 by The Mycological Society of America, Lawrence, KS 66044-8897 Three new species of Acanthostigma (Tubeufiaceae, Dothideomycetes) from Great Smoky Mountains National Park Itthayakorn Promputtha cellular pseudoparaphyses, cylindrical to clavate, Andrew N. Miller1 bitunicate asci, and cylindrical-fusiform to elongate- University of Illinois, Illinois Natural History Survey, fusiform, hyaline, transversely multiseptate ascospores 1816 South Oak Street, Champaign, Illinois 61820- (Re´blova and Barr 2000). Members of Acanthostigma 6970 usually occur as saprobes on terrestrial decomposing wood (Rossman 1987, Re´blova and Barr 2000) but also have been found on submerged wood in Abstract: Three new bitunicate ascomycetes belong- freshwater (Kodsueb et al. 2006). Some species are ing to the genus Acanthostigma are described from associated with helicosporous hyphomycete ana- terrestrial decomposing wood collected from Great morphs (Barr 1980, Re´blova and Barr 2000, Kodsueb Smoky Mountains National Park, USA. Phylogenetic et al. 2004, Tsui et al. 2006). analyses of the nuclear ribosomal 28S large subunit During our ongoing study of fungal diversity in and internal transcribed spacer region placed all three Great Smoky Mountains National Park (GSMNP) five species in the Tubeufiaceae and confirmed morpho- species of Acanthostigma were found, three of which logical analyses that these are distinct species. Expand- do not fit the description of any known species. These ed phylogenetic analyses of 28S large subunit includ- three newly discovered species are described, illus- ing taxa throughout the Dothideomycetes confirmed trated and compared morphologically and genetically the placement of Acanthostigma in the Tubeufiaceae. to other known species in the genus. A key to nine Acanthostigma filiforme differs from other Acanthos- accepted species in Acanthostigma is provided. tigma species in having longer ascospores with more septa. Acanthostigma multiseptatum can be distin- guished in having longer asci and longer ascospores MATERIALS AND METHODS with more septa. Acanthostigma septoconstrictum differs Morphological characterization.—Eighty-six collections of in having longer setae and asci and broader, asymmet- Tubeufiaceae were made from 2004 to 2007, but morpho- rical ascospores that are constricted at their septa. A logical examination occurred mostly throughout 2008. Due dichotomous key to Acanthostigma species is provided. to the large number of specimens collected during our Key words: Ascomycota, ITS, LSU, saprobe, inventory and because of the delayed morphological southern Appalachians, systematics, Tubeufia analyses cultures were not obtained from these specimens. Thus anamorphic data from cultures are not available for these species. Ascomata were squash-mounted in water and INTRODUCTION images of micromorphological structures were captured The taxonomic status of Acanthostigma de Not. (de with a QImaging QColor 3 digital camera mounted on Notaris 1863) has had an obscure history mostly due either a Leica MZ7.5 dissecting microscope with a Schott to the perceived loss of the type specimen for its type KL1500 fiber optics light source or an Olympus BX51 compound microscope with differential interference mi- species, A. perpusillum de Not. The recent rediscovery croscopy. Images were processed with Adobe Photoshop 7.0 and re-examination of the type specimen of A. (Adobe Systems Inc., Mountain View, California). A perpusillum (Re´blova and Barr 2000) along with minimum of 30 measurements was taken for all morpho- molecular analyses including the type species (Tsui logical structures when possible with NIH Image 1.63 et al. 2006, 2007) has clarified the circumscription of (National Institute of Health, Bethesda, Maryland). Means, Acanthostigma and confirmed its taxonomic place- which are shown in brackets, were calculated for asci and ment in the Tubeufiaceae. The taxonomy of ascospores. Ascomata were sectioned at ca. 5 mm with a Acanthostigma has been discussed adequately else- modified procedure of Huhndorf (1991). Taxa were where (Mu¨ller 1965; von Arx and Mu¨ller 1975; Barr compared with published species descriptions of Acanthos- 1977, 1980, 1990; Rossman 1987; Erikkson and tigma taxa listed on Index Fungorum (www.indexfungorum. Hawksworth 1998; Re´blova and Barr 2000; Kodsueb org, 1 Feb 2009). et al. 2006). Acanthostigma is characterized by having Molecular sequencing.—A DNeasyH Mini Plant Extraction minute, dark, setose ascomata with thick-walled setae, Kit (QIAGEN Inc., Valencia, California) was used to extract DNA from dried ascomata following the manufacturer’s Submitted 2 Apr 2009; accepted for publication 6 Oct 2009. protocols, except tissues were not ground in liquid nitrogen 1 Corresponding author. E-mail: [email protected] and final elution volume was 25 mL. Ascomata initially were 574 PROMPUTTHA AND MILLER:NEW ACANTHOSTIGMA SPECIES 575 rehydrated in 50 mL AP1 buffer 3–5 h, followed by freezing four and nine ambiguously aligned regions were delimited at 280 C for 3–14 d before DNA extraction. Due to their respectively in the expanded LSU, limited LSU and ITS relatively small size, 30–50 ascomata were used in the datasets. A portion of the phylogenetic signal was recovered extraction of DNA. The relative quantity of total genomic from all four regions in the limited LSU dataset and three of DNA was observed on a 1% TBE agarose gel stained with the nine regions in the ITS dataset by recoding them with the ethidium bromide. The entire internal transcribed spacer program INAASE (Lutzoni et al. 2000). The remaining six (ITS) region and the first 600 bp of the 59 end of 28S large ambiguously aligned regions in the ITS dataset and all 13 subunit (LSU) was PCR amplified on a Bio-Rad PTC 200 regions in the expanded LSU could not be recoded due to thermal cycler with PuReTaq Ready-To-GoTM PCR Beads their size so they were excluded from all analyses. The (GE Healthcare, Piscataway, New Jersey) and primers remaining unambiguously aligned characters in each dataset ITS1F/ITS5 and ITS4 or LROR and LR6 respectively were subjected to a symmetrical step-matrix to differentially (Vilgalys and Hester 1990, White et al. 1990, Gardes and weight nucleotide transformations with STMatrix 2.2 (Fran- Bruns 1993, Rehner and Samuels 1995). These reagents c¸ois Lutzoni and Stefan Zoller, Duke University), which were added to each PCR reaction: 1–5 mL DNA, 1.0 mL each calculates the costs for changes among character states based 10 mM primer and sufficient amount of sterile H2O to bring on the negative natural logarithm of the percentages of the total volume to 25 mL. Occasionally 2.5 mL BSA (bovine reciprocal changes between any two character states. Un- serum albumin, New England Biolabs, Ipswich, Massachu- equally weighted MP analyses were performed with 1000 setts) and/or 2.5 mL DMSO (dimethyl sulfoxide, Fisher stepwise random addition heuristic searches, TBR branch- Scientific, Pittsburgh, Pennsylvania) also were added to the swapping, MULTREES option in effect, zero-length branches PCR reaction. These thermo-cycling parameters were used: collapsed, constant characters excluded and gaps treated as initial denaturation at 95 C for 5 min, followed by 35 or 40 missing. Branch support was estimated by performing 100 cycles of 95 C for 30 s, 41 or 50 C for 15 s, and 72 C for 1 min bootstrap replicates (Felsenstein 1985) each consisting of 10 with a final extension step of 72 C for 10 min. After stepwise random addition heuristic searches as above. verification on an ethidium bromide-stained 1% TBE Modeltest 3.7 (Posada and Crandall 1998) was used to agarose gel, PCR products were purified with either a determine the best-fit model of evolution. The model of QIAquick PCR purification kit (QIAGEN Inc.) or ExoSAP- evolution selected by Modeltest for the LSU datasets was the ITH (Affymetrix, Cleveland, Ohio) following the manufac- GTR model (Rodrı´guez et al. 1990), while the model selected turer’s recommendations. A BigDyeH Terminator 3.1 cycle for the ITS dataset was the TrN model (Tamura and Nei sequencing kit (Applied Biosystems Inc., Foster City, 1993). Both models included a proportion of invariable sites California) was used to sequence both strands with a with the remaining sites subjected to a gamma distribution combination of these primers: ITS 5 ITS1F, ITS5, ITS1, shape parameter. ML analyses were performed on the limited ITS4; LSU 5 LROR, LRFF1, LRAM1, LR3, LR3R, LR5, LR6 LSU and ITS datasets with the above models with 100 stepwise (Vilgalys and Hester 1990, White et al. 1990, Gardes and random addition replicates and TBR branch-swapping with a Bruns 1993, Rehner and Samuels 1995, Huhndorf et al. reconnection limit of 12. Constant characters were included 2004). Sequences were generated on an Applied Biosystems and ambiguously aligned characters were excluded from the 3730XL high-throughput capillary sequencer. Each se- ML analyses. Bayesian analyses were performed on all datasets quence fragment was subjected to an individual BLAST with MrBayes 3.1 (Huelsenbeck and Ronquist 2001, Ronquist analysis to verify its identity. Sequences were assembled with and Huelsenbeck 2003) as an additional means of assessing Sequencher 4.7 (Gene Codes Corp., Ann Arbor, Michigan). branch support. Constant characters were included, the above models of evolution were implemented and Phylogenetic analyses.—Three datasets were assembled and 50 000 000 or 100 000 000 generations were sampled every analyzed: (i) an expanded LSU dataset consisting of nearly all 1000th generation resulting respectively in 50 000 or 100 000 Dothideomycetes taxa included in Schoch et al. (2006) along total trees for the ITS and limited LSU datasets and expanded with representatives of Acanthostigma; (ii) a limited LSU LSU dataset. The Markov chain always achieved stationarity dataset consisting of previously published anamorphic and after the first 100 000 generations, so the first 10 000 trees, teleomorphic taxa in the Tubeufiaceae along with the newly which extended well beyond the burn-in phase of each sequenced taxa generated during this study and (iii) an ITS analysis, were discarded.