Didymella
Didymella Sacc. ex Sacc., Syll. Fung. 1: 545 (1882).
Index Fungorum number: IF 1548; Facesoffungi number: FoF 07278, 418 morphological species (Species Fungorum 2022), 58 species with molecular data.
Saprobic or pathogenic on host. Sexual morph: Ascomata pseudothecial, immersed or erumpent, (sub-)globose to flattened, solitary or confluent, ostiolate, 2–5(–8)-layered, composed of pseudoparenchymatous cells. Asci cylindrical to clavate or saccate, 8-spored, bitunicate, arising from a broad hymenium among pseudoparaphyses. Ascospores mostly hyaline or brownish, ellipsoidal to cymbiform, uniseptate, symmetrical or asymmetrical, constricted at the septum, or multiseptate. Asexual morph: Conidiomata pycnidial, subglobose to ellipsoidal, becoming irregular, superficial on or immersed into the agar, solitary or confluent, ostiolate or poroid, sometimes with elongated necks. Micropycnidia occur in some species. Pycnidial wall pseudoparenchymatous, 2–8-layered, with a pigmented outer wall. Conidiogenous cells phialidic, hyaline, smooth, flask-shaped, ampulliform or doliiform. Conidia generally aseptate, variable in shape, smooth and thin-walled, i.e. llipsoidal to subglobose, cylindrical, oblong, ovoid, sometimes allantoid, hyaline, but in older cultures conidia may become pigmented, larger or septated conidia may occur in at least one species, mostly guttulate. Unicellular chlamydospores often abundantly formed in and on the agar and in the aerial mycelium, globose, intercalary, brown or (pale) olivaceous pigmented. Multicellular chlamydospores mainly alternarioid, terminal or intercalary, often in chains, brown or (pale) olivaceous (adapted from Chen et al. 2015).
Type species: Didymella exigua (Niessl) Sacc.
Notes: Didymella is characterised by pycnidial, subglobose to ellipsoidal conidiomata, hyaline, smooth, flask-shaped, ampulliform or doliiform conidiogenous cells, and ellipsoidal to subglobose, cylindrical, oblong, or ovoid conidia. The sexual morph is characterised by pseudothecial, immersed or erumpent ascomata, cylindrical to clavate or saccate, 8-spored asci and hyaline or brownish, ellipsoidal to cymbiform, uniseptate ascospores. Chen et al. (2015) emended Didymella to include Peyronellaea and several other phoma-like taxa. The taxonomic placement of Didymella has undergone several changes in recent years being placed in Pleosporaceae, Phaeosphaeriaceae, Venturiaceae, or Pleosporales incertae sedis (de Gruyter et al. 2009, Chen et al. 2009). De Gruyter et al. (2009) introduced a new family Didymellaceae for “Didymella clade” which comprised members of Phoma and related asexual genera. Didymella is a polyphyletic genus (Aveskamp et al. 2010). Didymella has been linked to Phoma sensu stricto (Woudenberg et al. 2009, Aveskamp et al. 2010) and Ascochyta (Chilvers et al. 2009, de Gruyter et al. 2009). Didymella is a distinct genus in Didymellaceae but requires revision as several species lack sequence data and are phylogenetically unresolved while others might belong to other genera. Molecular markers available for Didymella are ITS, LSU, Actin, BTUB, Calmodulin, RPB2 and TEF-1.
Recent News
Recent paper to be publishedRecent Genus
NothocladosporiumPhillipsiella
Curreya
Recent Species
Nothocladosporium syzygiiPhillipsiella atra
Curreya conorum
