Ceratocystidaceae Locq., Stud. Mycol. 68(1): 188 (2011)
MycoBank number: MB 515438; Index Fungorum number: IF 515438; Facesoffungi number: FoF 01248; 161 species.
Saprobic or pathogenic on plant materials and plants, parasitic in beetles, flies, or mites, and isolated from soil. Sexual morph: Ascomata perithecial, initially immersed to semi-immersed, becoming superficial, solitary or clustered; ascomatal bases globose, subglobose to obpyriform or ovoid, light brown or dark brown to black, clothed with spines or digitate or stellate appendages, ornamented or unornamented or with undifferentiated ornamental hyphae. Necks usually filiform, tapering and paler upwards. Ostiolar hyphae straight or divergent to convergent, aseptate, light brown to hyaline. Paraphyses lacking. Asci unitunicate, evanescent. Ascospores aseptate, hyaline, hat-shaped or varied in shape, ellipsoidal or elongate to slightly curved, with rounded ends, or oblong, cylindrical or narrowly fusiform to spindle-shaped, with eccentric wall thickening or surrounded by a sheath, accumulating in masses at tips of ostiole. Asexual morph: Conidiophores mononematous, single or aggregated in sporodochia or synnematous, septate, tapering towards apex, hyaline to pale brown or dark brown, unbranched or branched; in some genera such as Ceratocystis and Huntiella two types of conidiophores (primary and secondary) occur. Conidiogenous cells phialidic, borne terminally or laterally on vegetative hyphae, lageniform, tubular, rectangular, oblong cylindrical to flask-shaped, sometimes with a slightly flared collarette, subhyaline or pale brown, tapering towards the apex. Conidia unicellular, varied in shape, cylindrical to oblong, globose to subglobose, rectangular, single or formed in chains, with rounded or truncate ends, hyaline to pale brown, or becoming grey at maturity; in some genera with two types of conidia: (i) primary or bacilliform conidia hyaline, aseptate, cylindrical, and (ii) secondary or barrel-shaped conidia cylindrical to oblong, hyaline or becoming grey, aseptate, mostly in chains; aleurioconidia (some genera) globose to subglobose, ovoid to pyriform, single or in chains, hyaline or pale brown to brown (adapted from Réblová et al. 2011, Maharachchikumbura et al. 2016b).
Type genus – Ceratocystis Ellis & Halst.
Notes – Ceratocystidaceae (as “Ceratocystaceae”) was introduced by Locquin (1972), but was not validly published but validated by Réblová et al. (2011). It is currently placed in Microascales in the subclass Hypocreomycetidae (Réblová et al. 2011, de Beer et al. 2013b, Maharachchikumbura et al. 2016b). Within the order, it forms a monophyletic group, distinct from Gondwanamycetaceae based on strong bootstrap support (Réblová et al. 2011). Historically, Ceratocystidaceae and especially Ceratocystis included a highly heterogeneous group of species based on similar morphology. With the aid of multigene phylogenetic analyses, morphological characteristics and ecological preferences, several genera were delimited and placed in Ceratocystidaceae, which include Ambrosiella, Berkeleyomyces, Bretziella, Ceratocystis, Chalaropsis, Davidsoniella, Endoconidiophora, Huntiella, Meredithiella, Phialophoropsis and Thielaviopsis (Peyronel 1916, de Beer et al. 2014, 2017, Mayers et al. 2015, Nel et al. 2018).
Some asexual genera defined by similar characters are not readily identifiable which in the absence of molecular data, lead to difficulties in generic identification. DNA sequence data, the 60S ribosomal protein RPL10 (60S), nuclear ribosomal DNA large subunit (LSU) and mini- chromosome maintenance complex component 7 (MCM7) are suggested to delimit genera (de Beer et al. 2014, Marin-Felix et al. 2017). In addition, the internal transcribed spacer (ITS) regions and the 5.8S gene, partial β-tubulin (tub2), translation elongation factor 1α (tef1), second largest subunits of RNA polymerase II (rpb2), and/or the guanine nucleotide-binding protein subunit beta- like protein (MS204) gene regions are used to resolve taxa at the species level (de Beer et al. 2014, Marin-Felix et al. 2017, Liu et al. 2018). Huntiella chinaeucensis is illustrated in this study.