Pseudocercospora rosae
Pseudocercospora rosae J.F. Li, A. Mapook & K.D. Hyde, in Wanasinghe et al., Fungal Diversity 89: 15 (2018)
Index Fungorum number: IF554125 Facesoffungi number: FoF 03961
Pathogenic on leaves of Rosa canina. Sexual morph: Unknown. Asexual morph: Mycelium superficial on the substrate, composed of septate, branched, smooth, thin-walled, grey to dark grey coloured hyphae. Conidiophores absent, closely packed on the base. Conidiogenous cells (3.2-)3.8–5.5 µm long × (2.5-)2.8–3.4 µm diam (x̅ = 4.7 µm × 3.2 µm, n = 100), monoblastic, integrated, terminal, determinate or percurrent, cylindrical, doliiform, hyaline, smooth, colourless, thin-walled. Conidia 75−100 µm long × (8.5-)8.7–9.6(−10.2) µm diam. (x̅ = 90.2 µm × 9.3 µm, n = 100), acrogenous, holoblastic, solitary, hyaline, ellipsoidal, clavate, multiseptate, dry, simple, straight, curved, fusiform, borne in chain, smooth-walled, thin-walled.
Cultural characteristics: Conidia germinating on PDA within 14 hours and germ tubes produced from top cells. Colonies growing on PDA, hairy or cottony, grey to dark grey, reaching 5 mm in 20 days at 25ºC, mycelium superficial, effuse, radially striate, with regular edge, grey to dark grey coloured hyphae; Asexual spores and sexual spores were not formed within 60 days.
Material examined: THAILAND, Chiang Mai, on leaves of Rosa canina L. (Rosaceae), 14 December 2013, Ausana Mapook (HKAS100841, holotype), living culture = MFLUCC 14-0408，KUMCC 17-0264.
GenBank numbers: ITS: MG828952, LSU: MG829063.
Notes: Pseudocercospora species are mostly limited to single hosts (with a few exceptions), several species of a single host genus or with closely allied host genera (Braun et al. 2013). Farr and Rossman (2017) listed that Pseudocercospora species were recorded on Rosa centifolia, R. davurica, R. involucrate, R. multiflora and R. rugosa from China, Hong Kong, India and Korea. In this study we introduce the first record (Pseudocercospora rosae) of Pseudocercospora sp. on Rosa canina in Thailand. Pseudocercospora rosae is described herein as a new species and characterised with shorter conidiophores (up to 20) with non-stromata, subhyaline, fusiform, 1–3-septate conidia which differ with other Pseudocercospora species. Our phylogeny depicts that our new Pseudocercospora species is closely related to other unidentified species with moderate support.
Figure X. Pseudocercospora rosae (HKAS100841, holotype). a Dead plant tissues. b Colonies on dead stem. c-e Conidiophores. f Conidiophores with conidiogenous cells. g-s Conidia. Scale bars: a = 1 cm, b = 500µm, i = 100, c-e = 50µm, j-s = 50µm, f, h = 20µm.
References: Wanasinghe DN, Phukhamsakda C, Hyde KD, Jeewon R, et al. (2018) Fungal diversity notes 709–839: taxonomic and phylogenetic contributions to fungal taxa with an emphasis on fungi on Rosaceae. Fungal diversity 89(1): 1-236.
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