Phyllosticta owaniana G. Winter, Hedwigia 24: 31. 1885.
Index Fungorum: IF249730; Facesoffungi: FoFxxxxx; MycoBank: MB249730.
Pathogenic on leaves of Brabejum stellatifolium. Leaf spots amphigenous, irregular to subcircular, pale to medium brown, turning greyish with age, surrounded by a broad purplish border, and chlorotic margin. Sexual morph: Unknown. Asexual morph: Conidiomata (on PNA) up to 300 μm diam., pycnidial, solitary, black, erumpent, globose, exuding colourless conidial masses, pycnidia frequently with elongated neck on OA and MEA. Peridium up to 30 μm thick, composed of several layers of textura angularis, inner wall of hyaline textura angularis. Ostiole up to 10 μm diam., central. Conidiophores 10–30 × 4–5 μm, subcylindrical to ampulliform, reduced to conidiogenous cells, or with 1–2 supporting cells, that can be branched at the base. Conidiogenous cells 10–25 × 3–4.5 μm, terminal, subcylindrical, hyaline, smooth, coated in a mucoid layer, proliferating several times percurrently near apex. Conidia (10–)11–12(–13) × (7–)8(–9) μm, solitary, hyaline, aseptate, thin and smooth walled, granular, or with a single large central guttule, ellipsoid to obovoid, tapering towards a bluntly obtuse or narrow truncate base, 2–3 μm diam., enclosed in a thin persistent mucoid sheath, 1–2 μm thick, and bearing a hyaline, apical mucoid appendage, (5–)8–12(–15) × (1–)1.5 μm, flexible, unbranched, tapering towards an acutely rounded tip.
Culture characteristics: Colonies flat, spreading with sparse aerial mycelium and feathery, lobate margins, reaching 30 mm diam. on MEA, 40 mm diam. on PDA and 25 mm diam. on OA after 2 wk at 25 ºC. On OA surface iron-grey. On PDA surface and reverse iron-grey. On MEA surface and reverse iron-grey.
Representative isolates: South Africa, Western Cape Province, Cape Town, Table Mountain, on leaves of Brabejum stellatifolium, 1884, P. McOwan, holotype in B; Western Cape Province, Jonkershoek Nature Reserve, on leaf spot of Brabejum stellatifolium, 3 Jan. 1995, A. den Breeÿen, epitype CBS H-21396, CPC 1009 = CBS 776.97 = MBT176251 (ex-epitype culture).
Host: Brabejum stellatifolium (Wikee et al. 2013).
Known distribution: South Africa (Wikee et al. 2013).
GenBank Numbers: ITS - FJ538368, LSU - KF206293, TEF - FJ538426, ACT - KF289254, GPDH - JF343767.
Notes: Phyllosticta owaniana causes a serious leaf spot disease on Brabejum stellatifolium, and is generally found wherever this host occurs in South Africa. All isolates collected thus far are similar based on DNA sequence data, suggesting that it’s a common species on this host.
Wikee S, Lombard L, Nakashima C, Motohashi K, Chukeatirote E, Cheewangkoon R, McKenzie EHC, Hyde KD, Crous PW (2013) A phylogenetic re-evaluation of Phyllosticta (Botryosphaeriales). Studies in Mycology 76: 1–29.