Pseudoophiobolus mathieui
Pseudoophiobolus mathieui (Westend.) Phookamsak, Wanas., S.K Huang, Camporesi & K.D. Hyde,, in Phookamsak, Wanasinghe, Hongsanan, Phukhamsakda, Huang, Tennakoon, Norphanphoun, Camporesi, Bulgakov, Promputtha, Mortimer, Xu & Hyde, Fungal Diversity 87: 329 (2017)
Index Fungorum number: IF 553927; Facesofungi number: FoF 03804
Basionym: Sphaeria mathieui Westend., Bull. Acad. R. Sci. Belg., Cl. Sci., se´r. 2: no. 5 (1859)
Synonyms: Gnomonia mathieui (Westend.) Lambotte, Fl. myc. Belg. (Verviers) 2: 254 (1880)
Nodulosphaeria mathieui (Westend.) L. Holm, Symb. bot. upsal. 14(no. 3): 96 (1957)
Ophiobolus mathieui (Westend.) Sacc., Syll. fung. (Abellini) 2: 342 (1883)
Saprobic on flowering plants. Sexual morph: Ascomata 180–310 μm high (including papilla), 170–270 μm diam., dark brown to black, scattered, semi-immersed to erumpent through the host epidermis, subglobose to ampulliform, uni-loculate, glabrous, ostiolate, papillate. Papilla 90–105 μm high, 90–100 μm diam., mammiform to oblong, with rounded to truncate apex, composed of several layers of thick, brown to dark brown cells, arranged in a textura angularis to textura prismatica, ostiole central, with pore-like opening, lacking periphyses. Peridium 15–35 μm wide, composed of several layers, of brown to black, thick-walled, pseudoparenchymatous cells, inner layers comprising 1–2 layers of hyaline, flattened, thin-walled cells, arranged in textura prismatica, outer layers comprising several layers, of thickened, dark brown to black cells, arranged in textura angularis to textura globulosa. Hamathecium composed of dense, 2–4 μm wide, broadly cellular pseudoparaphyses, with small to large guttules, distinctly septate, slightly constricted at the septa, anastomosing at the apex, embedded in a hyaline gelatinous matrix. Asci (120–)125–140(–150) × 7–9 μm (x̄ = 137.3 × 8 μm, n = 30), 8-spored, bitunicate, fissitunicate, cylindrical to cylindric-clavate, short pedicellate, with furcate pedicel, apically rounded, with well-developed ocular chamber. Ascospores (104–)120–140(–160) × 2–3 μm (x̄ = 131 × 2.6 μm, n = 30), fasciculate, scolecosporous, yellowish to yellowish-brown, filiform, with rounded ends, tapered towards the lower cells, slightly swollen near the middle of the 4th or 5th cell from the apex, 13–15-septate, not constricted at the septa, smooth-walled. Asexual morph: Undetermined.
Culture characteristics: Colonies on PDA reaching 28–30 mm diam. after 4 weeks at 25–30 °C, medium dense, irregular, flattened to slightly raised, surface smooth, edge undulate, fluffy to floccose, slightly radiating at the margin, colony from above white to pale grey at the margin, greenish-grey to dark grey at the center, colony from below, radiated with dark brown concentric ring, greenish-grey to dark grey at the middle, paler towards the margin, not producing pigmentation in agar.
Material examined: ITALY, Province of Forlı `-Cesena
[FC], Teodorano—Meldola, dead stem of Salvia sp. (Lamiaceae), 12 October 2013, E. Camporesi, IT 1472 (MFLU 16-2043), living culture, MFLUCC 17-1784 = KUMCC 17-0159; ibid. Campigna—Santa Sofia, on dead stems of Origanum vulgare L. (Lamiaceae), 9 June 2014, E. Camporesi, IT1923 (MFLU17-0928); Campigna— Santa Sofia, dead stem of Ononis spinosa L. (Fabaceae), 25 August 2014, E. Camporesi, IT2074 (MFLU 17-0934), living culture, MFLUCC 17-1785 = KUMCC 17-0169.
GenBank:
Notes: Saccardo (1883) introduced Ophiobolus mathieui (Westend.) Sacc. to accommodate Sphaeria mathieui Westend. and described the species as having hyaline ascospores. Subsequently, Müller (1952) and Shoemaker (1976) examined and illustrated collections of O. mathieui from Europe and North America and mentioned that O. mathieui has hyaline to yellowish ascospores. Morphologically, our collections are typical O. mathieui in having pale yellowish ascospores swollen near the middle of the 4th cell (Müller 1952, Shoemaker 1976). Multi-gene phylogenetic analyses based on a combined LSU, SSU, TEF1- α and ITS sequence data showed that our strains formed a distinct clade distant from O. disseminans, the type species of Ophiobolus. Therefore, the new genus Pseudoophiobolus is established to accommodate the new combination, P. mathieui (= O. mathieui) and other ophiobolus-like taxa that are related to P. mathieui.
Figure x. Pseudoophiobolus mathieui (MFLU 16-2043). a Appearance of ascomata on the host surface. b Section through ascoma. c Section through peridium. d Pseudoparaphyses. e–g Asci. h–j Ascospores. Scale bars: a = 200 μm, b = 100 μm, c–j = 20 μm.
References:
Phookamsak R, Wanasinghe DN, Hongsanan S, Phukhamsakda C et al. 2017 – Towards a natural classification of Ophiobolus and ophiobolus-like taxa; introducing three novel genera Ophiobolopsis, Paraophiobolus and Pseudoophiobolus in Phaeosphaeriaceae (Pleosporales). Fungal Diversity. 87, 299–339.