Parastagonospora Quaedvl., Verkley & Crous, Stud. Mycol. 75: 362 (2013).
Index Fungorum number: IF 804435; Facesoffungi number: FoF 00260, 18 morphological species (Species Fungorum, 2022), 18 species with molecular data.
Saprobic or pathogenic on host. Sexual morph: Ascomata perithecial, immersed, globose, becoming depressed, dark brown to black, with central ostiole with upper region slightly papillate; ascomatal wall thin- or thick walled, composed of 2–6 layers of brown cells of textura angularis. Pseudoparaphyses filiform, hyaline, septate. Asci bitunicate, clavate, cylindrical, narrowly fusoid or curved, shortly stipitate, thick-walled, 8-spored. Ascospores fusoid or ellipsoidal, hyaline or subhyaline to pale brown, smooth-walled, transversely 3-euseptate, cells above central septum often broader than the lower ones, with acute rounded ends, constricted or not at each septum, sometimes with distinct oil droplets in each cell. Asexual morph: Conidiomata pycnidial, brown to black, erumpent or immersed to semi-immersed, subepidermal, globose to subglobose, ampulliform, or obpyriform, with central papillate ostiole, exuding creamy or pinkish conidial mass; conidiomatal wall composed of 2–4 layers of brown cells of textura angularis, or composed of 1–5 outer layers of dark brown cells and 1–3 inner layers of hyaline cells of textura angularis, or composed of an outer layer of brown to dark brown cells of textura globosa and an inner layer of pale brown to hyaline cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells phialidic, hyaline, smooth-walled, aggregated, lining the inner cavity, ampulliform to subcylindrical, broadly cylindrical or broadly conical, with percurrent proliferation near apex. Conidia hyaline or subhyaline, smooth-walled, thin- or thick-walled, cylindrical, subcylindrical or fusiform, granular to multi-guttulate, with obtuse or subobtuse apex and truncate base, rarely rounded at both ends, straight to gently curved, sigmoid, transversely 1–9-euseptate, sometimes constricted at the septa (adapted from Quaedvlieg et al., 2013).
Type species: Parastagonospora nodorum (Berk.) Quaedvl., Verkley & Crous
Notes: Parastagonospora was introduced by Quaedvlieg et al. (2013) with P. nodorum as type species. Parastagonospora is characterized by perithecial, immersed, globose, becoming depressed, dark brown to black ascomata, clavate, cylindrical, narrowly fusoid or curved, shortly stipitate asci and usoid or ellipsoidal, hyaline or subhyaline to pale brown, smooth-walled transversely 3-euseptate ascospores. The asexual morph is characterized by pycnidial, brown to black, erumpent or immersed to semi-immersed conidiomata, conidiomatal wall comprising brown cells of textura angularis, phialidic, hyaline, smooth-walled, aggregated conidiogenous cells and hyaline or subhyaline, smooth-walled, thin- or thick-walled, cylindrical, subcylindrical or fusiform conidia. Parastagonospora comprises taxa and serious cereal pathogens that were previously accommodated in Septoria/Stagonospora or Leptosphaeria/Phaeosphaeria (Quaedvlieg et al., 2013). Parastagonospora differs from Stagonospora in having phaeosphaeria-like sexual morph. In the phylogenetic analysis of Marin et al. (2019) based on the ITS and LSU sequences, all species of Parastagonospora formed a well-supported lineage except for P. phoenicicola which clustered in Phaeosphaeria for which a new combination was proposed. Marin et al. (2019) also synonymized P. cumpignensis and P. minima with Parastagonospora dactylidis based on phylogenetic evidence and occurrence on same host Dactylis (Li et al., 2015; 2016). Parastagonospora is currently a distinct genus in Phaeosphaeriaceae but it is uncertain if the genus is monophyletic as several species seems to be synonyms. Molecular markers available for Parastagonospora are LSU, SSU, ITS, RPB2 and TEF1.
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