Pseudorepetophragma zygopetali (O.L. Pereira, Meir. Silva & R.F. Castañeda) Phookamsak, Bhat & Hongsanan, in Hongsanan, Phookamsak, Bhat, Wanasinghe, Promputtha, Suwannarach, Sandamali, Lumyong, Xu & Xie, Frontiers in Cellular and Infection Microbiology 13(no. 1252387): 8
Index Fungorum Number: IF 900625, MycoBank Number: MB 900625, Facesoffungi Number: FoF 15863
≡ Repetophragma zygopetali O.L. Pereira, Meir. Silva and R.F. Castañeda, in Buyck, Duhem, Das, Jayawardena, Niveiro, Pereira, Prasher, Adhikari, Alberto, Bulgakov, Castañeda-Ruíz, Hembrom, Hyde, Lewis, Michlig, Nuytinck, Parihar, Popoff, Ramirez, Da Silva, Verma and Hofstetter, Cryptog. Mycol. 38(1): 135 (2017)
Etymology – Name derived from the plant host genus Zygopetalum.
Holotype – BrazIl, Minas Gerais, Araponga, Parque Estadualda Serrado Brigadeiro, on living leaves of Zygopetalummackayi (Or chidaceae), O.L.Pereira, 05 Apr. 2015, (holotype VIC 42946, culture ex-type COAD 1978).
Description – Colonies on living leaf leaves, effuse, black, forming a dark mycelial mat (sooty blotch). Mycelium mostly superficial, composed of septate, branched, dark brown, smooth hyphae. Conidiophores macronematous, simple, erect, straight or slightly geniculate towards the apex, annellate, 53-151 × 3.5-5 μm, 3-8 septate, dark brown to brown. Conidiogenous cells monoblastic, with 2-6 enteroblastic percurrent extensions. Conidial secession schizolytic. Conidia solitary, acrogenous, cylindrical to slightly obclavate, truncate at the base, rounded at the apex, 0-3 septate, 24-33 × 5-7 μm, brown, dark brown at the septa, thick-walled, smooth, dry.
Colonies cultured on PDA – reaching 25 mm diam. after 2 weeks at 25 °C in the dark; slightly irregularly lobate margins, aerial mycelium velvety, dark grey, reverse iron-grey, sterile.
Notes – Pseudorepetophragma zygopetali was first introduced as Repetophragma zygopetali by Buyck et al. (2017) due to its morphological resemblance with R. dennisii, but differing in the size of conidiophores and conidia (Castañeda-Ruiz et al., 2011; Buyck et al., 2017). The species was reported as a sooty blotch fungus that occurred on Zygopetalum mackayi in Brazil, while other species of Repetophragma have been mostly reported as hyperparasites or saprobes (Ellis, 1963; Castañeda-Ruiz et al., 2011; Index Fungorun, 2023). Its life mode is fitted well with the genera in Phaeothecoidiellaceae, and this was confirmed by phylogenetic evidence.
Figure 1 – Repetophragma zygopetali (holotype). A. Conidiogenous cell with enteroblastic percurrent extensions. B. Conidia. Scale bars: A = 5 μm, B = 10 μm.