Pleosporales » Didymellaceae

Ascochyta

Ascochyta Lib., Pl. crypt. Arduenna, fasc. (Liège) 1(Praef.): 8 (1830)

Synonym: Heracleicola Tibpromma et al., Fungal Divers. 75: 58. 2015 

Indexfungorum number: IF7239; Facesoffungi number: FoF ****

Sexual morph: Ascomata pseudothecial, immersed to erumpent, mostly subglobose or flattened occasionally irregular, solitary to aggregate, ostiolate, sometimes developing an elongated neck. Asci subcylindrical to subclavate, or saccate, slightly curved, bitunicate, 8-spored, short-stipitate. Pseudoparaphyses filamentous, septate, thin-walled, hyaline, conspicuous fructifications (lacking with the maturity). Ascospores ovoid to ellipsoidal, somewhat biconic, hyaline to yellowish into the asci, become brown when released, smooth, 1 and 3 septate, constricted at the septa, symmetrical or asymmetrical, uni-biseriate.  Asexual morph: Conidiomata pycnidial, superficial or immersed (in agar), ampulliform to mammiform or subglobose, occasionally irregular, solitary to aggregate, ostiolate, poroid opening form at the end of the growing. Pycnidial wall pseudoparenchymatous, several layers (1–8), pigmented outer wall. Conidiogenous cells annellidic or phialidic, smooth, hyaline, vary with shapes, ampulliform, cylindrical, doliiform, flask-shaped, obpyriform and subglobose. Conidia vary with shapes shape, allantoid, cymbiform, ellipsoidal, oblong, ovoid, subcylindrical, straight or slightly curved, hyaline or yellowish to pale brown, smooth- and thin-walled, with or without septa, mostly 1 or 2–3-septate, eguttulate or guttulate. Sometimes chlamydospores occur in old cultures.

Type species: Ascochyta pisi Lib., Pl. crypt. Arduenna, fasc. (Liège) 1(nos 1-100): no. 59 (1830)

Notes: Ascochyta was introduced by Libert (1830) with A. pisi Lib. is the type species. The peculiar morphological characters are the globose locules with perithecial protuberances immersed in the stroma. Species are mostly endophytes, pathogens and saprobes and associated with a number of hosts worldwide (Wijayawardene et al. 2017, Farr & Rossman 2020). Ascochyta was accommodated in family Didymellaceae (Hyde et al. 2013, Kirk et al. 2013). The asexual morphs of Ascochyta are coelomycetes (Chen et al. 2015). Ariyawansa et al. (2015) introduced Heracleicola to  Didymellaceae and Chen et al. (2017) synonymized the genus under Ascochyta. There are around 400 species epithets in the genus Ascochyta, however, the genus needs revision as more than 1000 records are available (Hyde et al. 2020). 

 

References:

 

Ariyawansa HA, Hyde KD, Jayasiri SC, Buyck B et al. 2015 Fungal diversity notes 111252-taxonomic and phylogenetic contributions to fungal taxa. Fungal diversity: an international journal of mycology 75, 274.

Boerema GH, Bollen GJ 1975 Conidiogenesis and conidial septation as differentiating criteria between Phoma and Ascochyta. Persoonia 8:111–444.

Boerema GH, de Gruyter J, Noordeloos ME, Hamers MEC 2004 – Phoma identification manual. Differentiation of specific and infra-specific taxa in culture. CABI Publishing, Wallingford, UK

Chen Q, Jiang JR, Zhang GZ, Cai L et al. 2015 Resolving the Phoma enigma. Studies in Mycology 82, 137–217.

Chen Q, Hou LW, Duan WJ, Crous PW et al. 2017 Didymellaceae revisited. Studies in Mycology 87, 105-159.

Chilvers MI, Rogers JD, Dugan FM, Stewart JE et al. 2009 – Didymella pisi sp. nov., the teleomorph of Ascochyta pisi. Mycological Research 113:391–400.

Farr DF, Rossman AY 2020 Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. http://nt.ars-grin.gov/fungaldatabases/

Hyde KD, Dong Y, Phookamsak R, Jeewon R et al. 2020 – Fungal diversity notes 1151–1276: taxonomic and phylogenetic contributions on genera and species of fungal taxa. Fungal Diversity 16:1–273.

Hyde KD, Jones EBG, Liu JK, Ariyawansa HA et al. 2013 Families of Dothideomycetes. Fungal Diversity 63, 1–313.

Jellis GJ, Punithalingam E 1991 Discovery of Didymella fabae sp. nov., the teleomorph of Ascochyta fabae, on faba bean straw. Plant Pathology 40:150–157.

Kaiser WJ, Wang BC, Rogers JD 1997 Ascochyta fabae and A. lentis: host specificity, teleomorphs (Didymella), hybrid analysis, and taxonomic status. Plant Disease 81:809–816.

Kirk PM, Stalpers JA, Braun U, Crous PW et al. 2013 A without prejudice list of generic names of fungi for protection under the International Code of Nomenclature for algae, fungi, and plants. IMA Fungus 4, 381–443.

Libert MA 1830 – Plantae Cryptogamae, quas in Arduenna collegit. Fasc 1, 100.

 

Last update: 02 May 2020 

 

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