Chalara

Fungalpedia – Note 3010, Chalara

Citation when using this data: Wenping Wu & Yongzhao D. 2023– Fungalpedia.

Index Fungorum, Facesoffungi, MycoBank, GenBank

Classification: Pezizellaceae, Helotiales, Leotiomycetidae, Leotiomycetes, Pezizomycotina, Ascomycota, Fungi

≡ Torula subgen. Chalara Corda, Icon. Fung (Prague) 2: 9, 1838.

= Chaetochalara B. Sutton & Piroz., Trans. Br. mycol. Soc. 48: 350, 1965.

Emended description: Colonies effuse, brown to dark brown, hairy. Mycelium partly immersed and partly superficial, composed of pale brown to brown, smooth, septate and branched hyphae. Anamorph: Stroma absent or present; if present, consisting of aggregated cells. Setae absent or present; if present, solitary, erect, straight or flexuous, simple, cylindrical, brown to dark brown, septate, tapering towards apex, acute or obtuse at the apex. Conidiophores macronematous, micronematous, scattered or aggregated from the basal stroma, erect, simple, or rarely branched, subcylindrical, pale brown, brown to very dark brown, smooth or verrucose, septate, consisting of a basal cell or septate stalk and a terminal phialide, with or without percurrent proliferations. Conidiogenous cells ampulliform, lageniform, obclavate, ellipsoidal, urceolate or subcylindrical, pale brown to dark brown, composed of a venter and a collarette, transition from venter to collarette gradual, abrupt or barely perceptible. Conidia holoblastic, cylindrical, obclavate, straight, hyaline, aseptate, smooth, with rounded or truncate ends, often with basal marginal frill or rarely fringes of wall material slightly rounded at the apex, extruded in short chains. Teleomorph: unknown.

Ecology/substrate/host: Saprobe on decaying plant materials including leaves, branches, stems, fruits and wood from terrestrial and submerged environments.

Geographical distribution: Widely distributed in worldwide (Nag Raj and Kendrick 1975).

Description and illustration: Ellis (1971); Nag Raj and Kendrick (1975).

Notes: Based on the morphological and phylogenetic analyses in this study, the genus Chalara, typified by C. fusidioides, is emended as a monophyletic genus in narrower concept to accommodate eight chalara-like fungi (Chalara africana, C. bambusicola, C. clidemiae, C. cylindrosperma, C. longiphora, C. platanicola and C. qinlingensis), which clustered as a strongly supported clade distinct from other chalaralike fungi. Morphologically the emended Chalara s. str. is characterized by solitary and unbranched conidiophore, terminal phialide consisting of a venter and a cylindrical collarette with deeply seated sporulating locus, and hyaline, aseptate and cylindrical conidia. Morphologically several other chalara-like genera such as Calycina, Cylindrochalara, Leochalara, Minichalara, Stipitochalara, Constrictochalara and anamorphs of Hymenoscyphus, share some similarity with Chalara s. str., but can be distinguished by different combinations of morphological characters such as conidiophores, conidiogenous cells and conidia. Furthermore, the separation of these genera are strongly supported by the phylogenetic analyses. In Leochalara and Minichalara, the conidiophores and phialides are subhyaline to pale brown, and transition from venters to collarettes are gradual; in Constrictochalara the phialides are constricted between venters and collarettes, and the conidia are clavate or not typical cylindrical. Several species of Hymenoscyphus produce chalara-like anamorphs, but differs from Chalara by sessile conidiogenous cells, relatively short collarettes, and shortcylindrical or globose conidia. The genus Stipitochalara can hardly be distinguished from Chalara s. str. in morphology, but phylogenetically belong to different family in Leotiomycetes.

However, the above treatment for Chalara s. str. is still problematic since the phylogenetic relationship of the type species C. fusidioides with those eight species was not known. Currently only one SSU sequence from an unauthorized strain of C. fusidioides was available in GenBank (AF203463) and its identity with C. fusidioides was doubtful. Johnson et al. (2019) briefly notified that based on a comparison of SSU sequences, the specimen identified as C. fusidioides (AF203463) could be congeneric with C. longipes which belongs to Hyaloscyphaceae. The phylogenetic analyses with SSU/LSU dataset in this study also points to the same conclusion. Although it has been recorded with broad distribution in North American and Europe, no living strain was deposited in any of those public culture collections such as ATCC, BCCM, CABI Fungi, CBS, CGMCC, DSMZ, IFO, etc. Thus, the phylogenetic relationship of C. fusidioides and other chalara-like fungi couldn’t be determined. Future studies on collecting of fresh material and epitypification of the type species is needed.

Based on the morphological study and phylogenetic analyses, a total of 17 species were accepted in this emended Chalara s. str. Among of them, eight species, C. africana, C. bambusicola, C. clidemiae, C. cylindrosperma, C. longiphora, C. pengii, C. platanicola and C. qinlingensis, were confirmed by the phylogenetic analysis. While the other 9 species, the type species C. fusidioides, C. bacillaris, C. clavatophora, C. cylindrophora, C. kirkii, C. sessilis, C. sinensis, C. sporendocladioides and C. versicolor, were without available of living strains, and thus their phylogenetic relationship with other chalara-like fungi remains to be studied in future. Morphologically the species assigned to Chalara s. str. are very variable in setae, conidiophores, phialides and conidia. Two species, C. africana and C. qinlingensis, were with setae among the conidiophores. Most species were with reduced conidiophores consisting of 1–2-celled basal stalk and a terminal phialide, however long and well-developed conidiophores with multiseptated stalk were also seen in C. brevispora, C. cylindrosperma, C. parvispora and several new species. Conidia of these species were always cylindrical or short-cylindrical, hyaline, aseptate, with obtuse or truncate ends, and formed in short or long easily dispersible chains. The basal frills of conidia were only found in C. brevipes and C. parvispora (Nag Raj and Kendrick 1975).