Exophiala yunnanensis and Exophiala yuxiensis (Chaetothyriales, Herpotrichiellaceae), two new species of soil-inhabiting Exophiala from Yunnan Province, China

Abstract

During a survey of soil fungi collected from Yunnan Province, China, two new species of Exophiala, E. yunnanensis and E. yuxiensis, were isolated from the soil of karst rocky desertification (KRD). The DNA sequences of these respective strains, including internal transcribed spacers (ITS), large subunit nuclear ribosomal RNA (LSU rRNA), partial small subunit (SSU) and β-tubulin (tub2) were sequenced and compared with those from species closely-related to Exophiala. Exophiala yunnanensis differs from the phylogenetically closely related E. nagquensis and E. brunnea by its smaller aseptate conidia. Exophiala yuxiensis is phylogenetically related to E. lecanii-corni, E. lavatrina and E. mali, but can be distinguished from them by its larger conidia. Full descriptions, illustrations and phylogenetic positions of E. yunnanensis and E. yuxiensis were provided.

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“…The habitats of species belonging to the Exophiala clade are very diverse, such as soil (E. alcalophiala, Exophiala pseudooligosperma, Exophiala yunnanensis and Exophiala yuxiensis), soil contaminated with aromatic hydrocarbons (Exophiala angulospora, Exophiala macquariensis and Exophiala xenobiotica), rock (Exophiala lamphunensis, Exophiala lapidea, Exophiala saxicola and Exophiala siamensis), leaf litter (Exophiala brunnea), rotten wood (Exophiala calicioides), bark of Abie alba (Exophiala abietophia) and fallen decorticated trunk (Exophiala lignicola) [6,7,[27][28][29][30][31][32][33][34]. Some species of the genus Exophiala have been isolated from drinking water, lakes and seawater (E. angulospora, Exophiala castellanii, E. halophiala, Exophiala lacus and Exophiala opportunistica), and they have also been discovered in indoor environments including bathrooms (E. alcalophila, Exophiala cancerae, Exophiala equina, Exophiala lecanii-corni and Exophiala mesophiala), kitchens (E. alcalophila, Exophiala jeanselmei, E. lecanii-corni, Exophiala oligosperma and E. xenobiotica,), refrigerator rubber seals (E. cancerae, Exophiala dermatitidis and E. oligosperma) and washing dispensers (E. alcalophiala) [27,28,34].…”

“…Species of the genus Exophiala are members of to the family Herpotrichiellaceae (Chaetothyriales, Ascomycota) and are commonly recognised as 'black yeast-like fungi' because their colonies are mainly dark, sometimes black, olive green, brown to black, olivaceous green and olivaceous grey [2][3][4][5][6]. The genus is mainly characterised by annellidic conidiogenous cells and yeast-like states [7]. However, members of the genus Exophiala have been reported as polymorphic fungi, on the basis of morphological changes, such as budding cells, phialidic, catenate and sympodial synanamorphs [6].…”