Cytospora predappioensis

Cytospora predappioensis Q.J. Shang, Norph., Camporesi & K.D. Hyde, in Hyde et al., Mycosphere 9(2): 376 (2018)

Index Fungorum number: IF 554083; Facesofungi number: FoF 3936

Saprobic on the bark. Sexual morph: Stromata 647–2225 µm wide, with the poorly developed interior, solitary to gregarious, immersed, becoming raised to erumpent the bark by the ostiolar canal, dark brown to black, glabrous, circular to irregular in shape, arranged with conspicuous, clustered, roundish to cylindrical prominent ostioles. Ascomata (excluding necks) 209–413 μm high, 194–360 µm diam. (x̄ = 300 × 277 μm, n = 10), perithecial, immersed in a stroma, dark brown to brown, globose to subglobose, glabrous, individual ostiole with the neck. Ostiolar canal 434–1185 μm high, 104–145 μm diam. (x̄ = 725 × 117 μm, n = 15), cylindrical, sulcate, periphysate. Peridium 23–40 μm wide, composed of two section layers, outer section comprising 5–8 layers, of relatively small, brown to dark brown, thick–walled cells, arranged in textura angularis, the inner part comprising 2–3 layers of hyaline cells of textura angularis. Hamathecium comprising only asci. Asci (23–)25–38(–50) × (3.5–)4–6.5(–8.5) μm ( x = 32 × 5.4 μm, n = 60), 8-spored, unitunicate, clavate, sessile, apically rounded to truncate, with a J^- apical ring. Ascospores (6.5–)7–10 (–12) × (1.5–)1.7–3(–3.5) μm (x̄ = 8.4 × 2.2 μm, n = 120), overlapping 1–3–seriate, hyaline, allantoid, aseptate, smooth-walled. Asexual morph: Coelomycetous. Conidiomata 540–665 μm, pycnidial, with 2–4-loculate, appearing as beige-white to brown, watery, rounded, conidial masses, superficial, solitary or aggregated, globose, shiny, with white to brown mycelium covering the surface. Pycnidial walls 13–21 μm wide, comprising several layers of brown, compressed hyphae, arranged in a textura intricata. Conidiogenous cells 8.5–10.5(–11) × 1.5–2.7(–3) (x̄ = 9.7 × 2 μm, n = 5), cylindrical to clavate, holoblastic, straight. Conidia (4.5–)5–6.5(–8) × (0.8–)1–1.5(–1.8) (x̄ = 6 × 1.4 μm, n = 75), hyaline, allantoid, unicellular, smooth-walled.

Culture characteristics: Ascospores germinating on PDA within 24 hrs. Germ tubes produced from all sides. Colonies on PDA reaching and 5–5.5 cm diam. after 15 days at room temperature, colonies circular to irregular, medium dense, flat or effuse, slightly raised, with edge fimbriate, fluffy to fairy fluffy, white from above, white to yellow from below after 5 days, dark brown from above, brown to dark brown from below after 15 days; not producing pigments in agar..

Material examined: ITALY, near Predappio (Province of Forlì-Cesena [FC]), on a dead land branch of Ostrya carpinifolia (Betulaceae), 20 March 2017, E. Camporesi, IT 3289A (MFLU 17-0846, KUN-HKAS 100915), living culture, MFLUCC 18-1202. ITALY, Camposonaldo, Santa Sofia (Province of Forlì-Cesena [FC]) Province, on a dead land branch of O. carpinifolia, 17 March 2017, E. Camporesi, IT 3289 (MFLU 17-0836, KUN-HKAS 102162.

Notes: The phylogenetic analysis revealed that the newly obtained isolates (MFLUCC 18-1202 (from Italy) and MFLUCC 18-1205 (from China) clustered together with taxa of Cytospora ceratospermopsis (CFCC 89626 and CFCC 89627), Cytospora predappioensis (MFLUCC 17-2458, MFLUCC 17-0327) and Cytospora sacculus (CFCC 89624) and can be identified as C. predappioensis. To confirm this identification, the single gene comparison of ITS, LSU and ACT gene regions was carried out between MFLUCC 18-1202, MFLUCC 18-1205 and MFLUCC 17-2458 (the ex-type of C. predappioensis), the result showed that there is no significant difference in nucleotides of ITS, LSU, and ACT gene. In addition, these new collections are morphologically identical to C. predappioensis except their longer ostiolar canals (Hyde et al. 2018). Therefore, Shang et al. (2020) conservatively identify new isolate as C. predappioensis and speculate that the phylogeny of this taxon is complex.