Fungalpedia – Note 1022, Melanoctona

 

Melanoctona. Qing Tian, Doilom & K.D. Hyde.

Citation when using this data: Tian Q et al. 2021 (in prep.) – Fungalpedia, Ascomycota.

Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1

Classification: Herpotrichiellaceae, Chaetothyriales, Chaetothyriomycetidae, Eurotiomycetes, Pezizomycotina, Ascomycota, Fungi

Saprobic on decaying wood in terrestrial habitats. Colonies superficial, effuse, scattered, dark brown to black. Sexual morph: Undetermined. Asexual morph: hyphomycetous. Conidiophores mononematous, macronematous, unbranched, erect, straight or flexuous, smooth, dark brown. Conidiogenous cells integrated, sympodially proliferating, terminal and intercalary, enteroblastic, phialidic, pale brown or subhyaline. Conidia acrogenous, brown to black, ovoid, muriform, rounded at base and apex, smooth-walled.

Notes – Melanoctona was introduced to accommodate an asexual species in Herpotrichiellaceae and is typified by M. tectonae which forms a distinct clade (Tian et al. 2016). To date, the asexual morphs of Herpotrichiellaceae are predominantly black yeasts with holoblastic, conidiogenous cells which proliferate percurrently and aseptate or septate conidia, and include Cladophialophora, Exophiala, Fonsecaea, Phialophora, Ramichloridium and Rhinocladiella species (Müller et al. 1987, Untereiner et al. 1995, Crous et al. 2007, Gueidan et al. 2014, Liu et al. 2015), and undetermined pyricularia-like taxa (Klaubauf et al. 2014). Species of Exophiala are characterized by brown, aseptate to 1-septate conidia, forming successively from the apex of the sporogenous cell and aggregating in slime balls (Carmichael 1966). Phialophora produces hyaline to pigmented, aseptate conidia, forming from flask-shaped to straight phialides (Harrington & Mcnew 2003). Cladophialophora has aseptate, hydrophobic conidia and is mostly isolated as clinical fungi (Badali et al. 2011). Fonsecaea has melanized conidiophores with cylindrical denticles and aseptate, acrogenous conidia (de Hoog et al. 2000a). Melanoctona however, has dark brown to black, muriform or multi-septate, acrogenous, conidia. Melanoctona tectonae was isolated from a dead branch of Tectona grandis as a saprobe, while other asexual morphs in Herpotrichiellaceae have been isolated as human pathogens (such as human chromoblastomycosis) (de Hoog et al. 2007). Melanoctona was collected on decaying wood of Tectona grandis in Chiang Rai Province, Thailand and phylogenetic analyses of combined ITS, LSU sequence data place Melanoctona in a distinct lineage in Herpotrichiellaceae.

Type species: Melanoctona tectonae Qing Tian, Doilom & K.D. Hyde.

Other accepted species: Species Fungorum – search Melanoctona.

 

image

 

           Figure 1 – Melanoctona tectonae (MFLU 15-3528, holotype). a Appearance of fungus on a dead branch of Tectona grandis. b, c Conidiascattered on the surface of the wood. d, e Conidia. Melanoctona tectonae (MFLU 15-3528, holotype). a Appearance of fungus on a dead branch of Tectona grandis. b, c Conidia scattered on the surface of the wood. d, e Conidia.

 

References

Badali H, Prenafeta-Boldú FX, Guarro J, Klaassen CH et al. 2011 – Cladophialophora psammophila, a novel species of Chaetothyriales with a potential use in the bioremediation of volatile aromatic hydrocarbons. Fungal Biologyogy 115, 1019–1029.

Carmichael JW. 1966 – Cerebral mycetoma of trout due to a Phialophora-like fungus. Sabouraudia 5(1), 120–123.

Crous PW, Schubert K, Braun U, de Hoog GS et al. 2007 – Opportunistic, human-pathogenic species in the Herpotrichiellaceae are phenotypically similar to saprobic or phytopathogenic species in the Venturiaceae. Studies in Mycology 58, 185–217.

de Hoog GS, Guarro J, Gené J, Figueras MJ. 2000a – Atlas of Clinical Fungi, 2nd ed. Centraalbureau voor Schimmelcultures, Utrecht, Universitat Rovira i Virgili, Reus.

de Hoog GS, Nishikaku AS, Fernández Zeppenfeldt G, Padín-González C et al. 2007 – Molecular analysis and pathogenicity of the Cladophialophora carrionii complex, with the description of a novel species. Studies in Mycology 58, 219–234.

Gueidan C, Aptroot A, da Silva Cáceres ME, Badali H et al. 2014 – A reappraisal of orders and families within the subclass Chaetothyriomycetidae (Eurotiomycetes, Ascomycota). Mycological Progress 13, 1027–1039.

Harrington TC, Mcnew DL. 2003 – Phylogenetic analysis places the Phialophora-like anamorph genus Cladophora in the Helotiales. Mycotaxon 87, 141–151.

Klaubauf S., Tharreau D., Fournier E., Groenewald J.Z et al. 2014 – Resolving the polyphyletic nature of Pyricularia (Pyriculariaceae). Studies in Mycology 79, 85–120.

Liu JK, Hyde KD, Gareth EBG, Ariyawansa HA et al. 2015 – Fungal Diversityity notes 1–110: Taxonomic and phylogenetic contributions to fungal species. Fungal Diversity 72, 1–197.

Muller E, Pehini O, Fisher PJ, Samuels GJ et al. 1987 – Taxonomy and anamorphs of the Herpotrichiellaceae with notes on generic synonymy. Transactions of the British Mycological Society 88, 63–74.

Tian Q, Doilom M, Luo ZL, Chomnunti P et al. 2016 – Introducing Melanoctona tectonae gen. et sp. nov. and Minimelanolocus yunnanensis sp. nov. (Herpotrichiellaceae, Chaetothyriales). Cryptogamie, Mycologie 37, 477–492.

Untereiner WA, Straus NA, Malloch D. 1995 – A molecular-morphotaxonomic approach to the systematics of the Herpotrichiellaceae and allied black yeasts. Mycological Research 99, 897–913.

 

Entry by

Qing Tian, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand, School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand

 

Published online 16 December 2021

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