title: Minutisphaerales (Dothideomycetes, Ascomycota): a new order of freshwater ascomycetes including a new family, Minutisphaeraceae, and two new species from North Carolina, USA.
abstract: Minutisphaera is a recently established genus of freshwater Dothideomycetes characterized by small, globose to subglobose or apothecioid, erumpent to superficial, brown ascomata; fissitunicate, eight-spored, ovoid to obclavate asci; and 1-2-septate, clavate to broadly fusiform, hyaline to pale brown ascospores with or without a gelatinous sheath and filamentous appendages. The genus currently contains two species: M. fimbriatispora, the type species, and M. japonica. The higher-level phylogenetic relationship of Minutisphaera within the Dothideomycetes currently is unresolved. To establish the phylogenetic position of Minutisphaera within the Dothideomycetes and evaluate the phylogenetic affinities of newly collected Minutisphaera-like taxa, we sequenced three rDNA regions-18S, ITS1-5.8SITS2 (ITS) and 28S nuc rDNA, and a protein-coding gene, MCM7, for newly collected strains of Minutisphaera. Based on maximum likelihood and Bayesian analyses of a combined dataset (18S and 28S) composed of 167 taxa, a more refined dataset (28S and MCM7) comprising 52 taxa and a separate ITS dataset, and an examination of morphology, we describe and illustrate two new species of Minutisphaera. The Minutisphaera clade was strongly supported within the Dothideomycetes with likelihood and Bayesian statistics but did not share phylogenetic affinities with any existing taxonomic group within the Dothideomycetes. We therefore establish a new order, Minutisphaerales, and new family, Minutisphaeraceae, for this monophyletic clade of freshwater ascomycetes. Chemical analysis of the organic extract M. aspera (G427) resulted in isolation and characterization of five known secondary metabolites, of which four were dipeptides (1-4) and one an aromatic polyketide (5). Conversely, two aromatic polyketides (5, 6) were isolated and identified from the organic extract of M. parafimbriatispora (G156-4). The isolated compounds were tested for their antimicrobial activity against an array of bacteria and fungi. Compound 6 showed promising activity against Staphylococcus aureus and Mycobacterium smegmatis with minimal inhibitory concentration values of 30 and 60 μg/mL, respectively.
authors: Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, North Carolina 27402 haraja@uncg.edu.
authors: Huzefa A
authors: HA
authors: Raja
authors: Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, North Carolina 27402.
authors: Tamam
authors: T
authors: El-Elimat
authors: Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, North Carolina 27402.
authors: Nicholas H
authors: NH
authors: Oberlies
authors: Department of Plant Biology, University of Illinois, Urbana, Illinois 61801.
authors: Carol A
authors: CA
authors: Shearer
authors: Illinois Natural History Survey, University of Illinois, Champaign, Illinois 61820.
authors: Andrew N
authors: AN
authors: Miller
authors: Faculty of Agriculture and Life Sciences, Hirosaki University, Bunkyo-cho, Hiroskaki, Aomori 036-8561, Japan.
authors: Kazuaki
authors: K
authors: Tanaka
authors: The United Graduate School of Agricultural Sciences, Iwate University, 18-8 Ueda 3 chome, Morioka 020-8550, Japan.
authors: Akira
authors: A
authors: Hashimoto
authors: Las Muros, 09420 Rimont, France.
authors: Jacques
authors: J
authors: Fournier
mesh_terms: D001203:Ascomycota / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D044822:Biodiversity; D004271:DNA, Fungal / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D017753:Ecosystem; D005618:Fresh Water / Q000382:microbiology*; D019015:Geologic Sediments / Q000382:microbiology*; D025301:Hyphae / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009657:North Carolina; D010802:Phylogeny; D061065:Polyketides / Q000378:metabolism; D013172:Spores, Fungal / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D061065:Polyketides
keywords: Aquatic; microfungi; submerged wood; systematics