Pleosporales » Didymellaceae

Ascochyta

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

= Didymochaeta Sacc. & Ellis, Bull. Torrey bot. Club 25: 510 (1898)

Facesoffungi number: FoF 07121

 

Dothideomycetes, Pleosporomycetidae, Pleosporales, Didymellaceae

Saprobic or parasitic on the host plant. Sexual morph: see Chilvers et al. (2009). Asexual morph: Conidiomata dark brown to black, pycnidial, solitary to gregarious or confluent, immersed to semi-immersed, globose or subglobose, unilocular, glabrous, papillate, ostiolate. Ostiole single, circular, papillate or non-papillate, centrally located. Conidiomatal wall composed of thick-walled, dark brown to paler cells of textura angularis. Conidiophores arising all around the cavity of the conidiomata, reduced to conidiogenous cells. Conidiogenous cells hyaline, enteroblastic, annellidic or phialidic, subcylindrical to lageniform or ampuliform to dolliform, determinate, smooth-walled. Conidia hyaline, oblong to cylindrical, straight or slightly curved, 0-2-septate, slightly constricted at the septa, smooth-walled, guttulate (Chen et al. 2015).

 

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

 

Notes: Most species of Ascochyta have been shown to highly host specific on Campanulaceae, Chenopodiaceae, Leguminosae, Poaceae, Solanaceae and Umbelliferae (Chen et al. 2015, 2017). Ascochyta has pycnidial conidiomata producing hyaline or sometimes pale brown, ovoid, oblong, subcylindrical or ellipsoidal, mostly two-celled conidia (Boerema and Bollen 1975, Boerema 2004). This genus is often confused with Phoma, as both genera are similar in morphology, physiology, pathogenicity and nucleotide sequences (Boerema and Bollen 1975, Mendes-Pereira et al. 1999, Davidson et al. 2009, De Gruyter et al. 2009, 2010, Aveskamp et al. 2010). Chen et al. (2015) clarified the generic circumscriptions of Ascochyta and Phoma, and emended the generic concept for both genera based on multigene sequence data of ITS, LSU, rpb2 and tub2 and morphology characters. Since then, three additional species were described, A. boeremae L.W. Hou et al., A. italica Tibpromma et al. and A. rosae Tibpromma et al. (Chen et al. 2017, Tibpromma et al. 2017). However, A. rosae Tibpromma et al. with both sexual and asexual morph is identical to A. herbicola in morphology and phylogeny, and is synonymized under the latter in the present study. We describe a new taxon A. neopisi on Colutea arborescens (Fabaceae) from Italy.

 

Distribution: worldwide.

 

References:

 

Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–80.

 

 

 

 

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