Bionectriaceae Samuels & Rossman, Stud. Mycol. 42: 15 (1999)
Index Fungorum number: IF82088; 579 species.
Herbicolous, corticolous, lichenicolous or fungicolous, some are coprophilous, most occur in terrestrial or freshwater habitats, less common in marine habitats. Sexual morph: Ascomata superficial on the substratum or embedded in a weakly or well-developed erumpent stroma, solitary or densely aggregated, crowded, perithecial, rarely cleistothecial, if perithecial, globose, subglobose to pyriform, if cleistothecial, globose, white, yellow, orange, reddish-brown, greenish or purple to violet, without changing colour in KOH or lactic acid, smooth to rough, or warted, ostiolate or lacking ostioles. Periphyses present or absent. Peridium composed of 1–3 layers. Asci (2–)8- spored, unitunicate, clavate, saccate, cylindrical, sessile or short pedicellate, rarely evanescent, apex simple or with an inconspicuous or distinct, J-, apical ring. Ascospores uniseriate, biseriate, multiseriate or irregular, hyaline, aseptate to multi-septate, sometimes muriform, globose, fusiform, ellipsoid or broadly ellipsoid, smooth-walled, spinulose to tuberculate or striate. Asexual morph: Hyphomycetous or less commonly ceolomycetous, acremonium-, gliocladium-like, gyrostroma-like or penicillium-like, sometimes conidia produced on hyphae. Conidiophores dimorphic or monomorphic, mostly sporodochial or synnematous, hyaline, subhyaline to brown or blackish brown, smooth to finely echinulate-walled. Conidiogenous cells phialidic. Phialides cylindrical to flask-shaped. Conidia unicellular to multi-septate, ellipsoidal, fusiform to subfusiform, sometimes with papillate or truncate ends, hyaline to greenish hyaline or olivaceous grey, smooth or striatewalled. Chlamydospores present or absent (adapted from Rossman et al. 1999).
Type genus – Clonostachys Corda
Notes – Rossman et al. (1999) introduced Bionectriaceae to accommodate 26 genera
including five cleistothecial genera. Four cleistothecial genera were accepted in the family based on phylogenetic analysis of the LSU gene by Rossman et al. (2001). Rossman et al. (2001) reported that Bionectriaceae is monophyletic within Hypocreales, by including those genera and related asexual morphs. Maharachchikumbura et al. (2015, 2016b) listed 39 genera in the family. Wijayawardene et al. (2018a) accepted Didymostilbe and Virgatospora in Stachybotryaceae.
Stromatocrea and Vesicladiella, previously included in Bionectriaceae by Maharachchikumbura et al. (2015, 2016b), were not considered by Wijayawardene et al. (2018a). Wijayawardene et al. (2018) accepted 39 genera in the family including Bullanockia, Fusariella, Paracylindrocarpon and Synnemellisia. Spicellum was listed under Bionectriaceae in Wijayawardene et al. (2018). However, Spicellum was synonymized under Trichothecium (Myrotheciomycetaceae, Hypocreales) based on morphology and DNA sequence data by Summerbell et al. (2011). LSU is commonly used and the available gene for phylogenetic analysis of Bionectriaceae. However, few additional sequence data are available for the family except for well-studied genera such as Geosmithia and Clonostachys (Voglmayr & Jaklitsch 2019). Many genera need to be recollected and sequenced and their placement in, or exclusion from Bionectriaceae or synonymies confirmed.
Ecological and economic significance of Bionectriaceae
Only few plant-pathogenic species are recognized in Bionectriaceae e.g. Nectriella pironi causing galls on stems and leaves of woody plants (Alfieri et al. 1980). Acremonium species are causal agents of rose dieback in Iran (e.g. A. sclerotigenum) (Domsch et al. 2007, Mirtalebi et al. 2017). Some species of Acremonium and Clonostachys are effective biological control agents (Auer & Ludwig-Müller 2014, Sutton & Mason 2017, Bobeck & Pearce 2017). Clonostachys rosea (strain BVT Cr-7) is a beneficial biological control agent for fungal plant pathogens such as Botrytis cinerea, Sclerotinia sclerotiorum, Pythium, Alternaria, Monilinia, Colletotrichum, Cladosporium, Rhizoctonia., Streptomyces, Didymella and Fusarium (Sutton & Mason 2017). Furthermore, strain 88-710 helps to protect plants against environmental stresses, hence promoting plant growth and productivity (Sutton & Mason 2017, Bobeck & Pearce 2017). Acremonium alternatum strains are used as biological control agents in several countries, to control clubroot pathogen, Plasmodiophora brassicae, on Chinese cabbage (Brassica rapa) and oilseed rape (Brassica napus) (Auer & Ludwig-Müller 2014).