Dothiorella americana
Dothiorella americana Úrbez-Torr., Peduto & Gubler, in Úrbez-Torres, Peduto, Striegler, Urrea-Romero, Rupe, Cartwright & Gubler, Fungal Diversity 52: 184 (2012)
Mycobank: 519956
Etymology: Name after the Continent where it was first found.
Pycnidia subimmersa, solitaria, globosa, usque ad 650 μm diameter. Cellulae conidiogenae holoblasticae, hyalinae, cylindricae vel subcylindicae 7–16 × 4–6 μm. Conidia primo hyalina, unicellularia, ovalia vel obovoidea, apice rotundata basi truncata (13.5-)14.2-15.8(-17.2) × (5-) 5.7-6.6(-7.9) μm (statura media 15 × 6.1) (longitudo/latitudo = 2.4 ± 0.2). Mycelio confuto, primo olivaceous medius et albus ora demum viridis atrer.
Pycnidia formed on PDA within 2 weeks, solitary, stromatic, globose, black, covered with moderate mycelium, up to 650 μm wide, thick-walled, unilocular, with a central ostiole. Conidiophores reduced to conidiogenous cells. Conidiogenous cells holoblastic, hyaline, cylindrical to subcylindrical 7–16 × 4–6 μm. Conidia produced in culture initially hyaline, unicellular, becoming light brown to dark brown and 1-septate while still attached to the conidiogenous cells. Conidia from light to dark brown, thin-walled, oval to ovoid, round apex and truncate base, (13.5-)14.2-15.8(-17.2) × (5-)5.7-6.6(-7.9) μm (av. ± 15 × 6.1) (l/w ratio = 2.4 ± 0.2).
Cultural characteristics: Suppressed mycelium on PDA. Mycelia/colonies on PDA initially olivaceous-buff (21”’d) in the center of the colony and white at the edge becoming olivaceous (21”’m) within 7 days and turning dark green (35’m) within 28 days on the surface. Colony violaceous grey (59””’) at the reverse after 28 days. Colonies reaching 90 mm diameter on PDA after 5 days in the dark at 25°C. Cardinal temperatures for growth between 10 and 35°C. Optimum temperature for growth 20–25°C.
Habitat: Interspecific hybrid grape cultivar Vignoles (Ravat 51)
Known distribution: state of Missouri, USA
Material examined: USA, Purdy, Missouri, R. K. Striegler and G. M. Leavitt, Vignoles (UCD2252MO;
Holotype: culture ex-type CBS128309); USA, St. Genevieve, Missouri, R. K. Striegler and G. M. Leavitt, Chardonel (UCD2272MO; CBS128310).
Figs. 34–39 Dothiorella americana CBS128309. 34, 7-days-old colony on PDA. 35, 28-days-old colony on PDA. 36, conidiomata on PDA culture. 37, conidia developing on conidiogenous cell. 38 and 39, pigmented, 1-septate conidia. Scale bars: 36 = 1000 μm; 37, = 5 μm; 38 and 39=10 μm.