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- Urbina, Hector, et al.
(author)
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Multilocus phylogenetic study of the Scheffersomyces yeast clade and characterization of the N-terminal region of xylose reductase gene.
- 2012
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:6, s. e39128-
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Journal article (peer-reviewed)abstract
- Many of the known xylose-fermenting (X-F) yeasts are placed in the Scheffersomyces clade, a group of ascomycete yeasts that have been isolated from plant tissues and in association with lignicolous insects. We formally recognize fourteen species in this clade based on a maximum likelihood (ML) phylogenetic analysis using a multilocus dataset. This clade is divided into three subclades, each of which exhibits the biochemical ability to ferment cellobiose or xylose. New combinations are made for seven species of Candida in the clade, and three X-F taxa associated with rotted hardwood are described: Scheffersomyces illinoinensis (type strain NRRL Y-48827T = CBS 12624), Scheffersomyces quercinus (type strain NRRL Y-48825T = CBS 12625), and Scheffersomyces virginianus (type strain NRRL Y-48822T = CBS 12626). The new X-F species are distinctive based on their position in the multilocus phylogenetic analysis and biochemical and morphological characters. The molecular characterization of xylose reductase (XR) indicates that the regions surrounding the conserved domain contain mutations that may enhance the performance of the enzyme in X-F yeasts. The phylogenetic reconstruction using XYL1 or RPB1 was identical to the multilocus analysis, and these loci have potential for rapid identification of cryptic species in this clade.
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- Urbina, Hector, 1977-, et al.
(author)
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Scheffersomyces cryptocercus: a new xylose-fermenting yeast associated with the gut of wood roaches and a taxonomic revision of the Sugiyamaella yeast clade
- 2012
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In: Mycologia. - : Informa UK Limited. - 0027-5514 .- 1557-2536. ; 105:3, s. 650-660
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Journal article (peer-reviewed)abstract
- The gut of wood-feeding insects is a microhabitat for a specialized community of microbes, including bacteria and several groups of eukaryotes such as nematodes, parabasalids and fungi. The characterization of gut yeast communities from a variety of insects has shown that certain yeasts often are associated with the insects. The gut of wood-feeding insects is rich in ascomycete yeasts and in particular xylose-fermenting (X-F) and assimilating yeasts have been consistently present in the gut of lignicolous insects. The objective of this study was the characterization of the yeast flora from the gut of the wood roach Cryptocercus sp. (Blattodea: Cryptocercidae). Five wood roaches were collected along the Appalachian Trail near the border between Tennessee and North Carolina, USA. We isolated 18 yeast strains from the wood roaches identified as Sugiyamaella paludigena and Sugiyamaella lignohabitans, xylose-assimilating yeasts, and Scheffersomyces cryptocercus (NRRL Y-48824T = CBS 12658) a new species of X-F yeast. The presence of X-F and certain non X-F yeasts in the gut of the subsocial wood roach Cryptocercus sp. extends the previous findings of associations between certain ascomycete yeasts and lignicolous insects. New combinations were made for 13 asexual members of the Sugiyamaella clade.
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- Urbina, Hector, 1977-, et al.
(author)
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The gut of Guatemalan passalid beetles : A habitat colonized by cellobiose- and xylose-fermenting yeasts
- 2013
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In: Fungal ecology. - : Elsevier BV. - 1754-5048 .- 1878-0083. ; 6:5, s. 339-355
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Journal article (peer-reviewed)abstract
- The gut of insects is a productive environment for discovering undescribed species of yeasts, and the gut of wood-feeding insects of several families is especially rich in yeasts that carry out the fermentation of cellobiose and xylose. Passalid beetles (Passalidae, Coleoptera) live in dead wood that they ingest as their primary food source. We report the isolation, molecular identification and physiological characterization of 771 yeast cultures isolated from the gut of 16 species of passalids collected in nine localities in Guatemala. Ascomycete yeasts were present in the gut of every passalid studied, and the xylose-fermenting (X-F) yeasts Scheffersomyces shehatae and Scheffersomyces stipitis were the most abundant taxa isolated. The gut of the beetles also contained undescribed cellobiose-fermenting and X-F species in the Lodderomyces,Scheffersomyces and Spathaspora, and undescribed species in Sugiyamaella clades as well as rare yeast species in the Phaffomyces and Spencermartinsiella clades. Basidiomycete yeasts in the generaCryptococcus and Trichosporon were also common. The yeast species richness was influenced by the host species and the substrate, and gut-inhabiting yeasts have the ability to survive the differing physiological conditions of several gut compartments.
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