Bambusicola triseptatispora Phookamsak, D.Q. Dai & K.D. Hyde, sp. nov. Index Fungorum number: IF552024
Etymology: The epithet Btriseptatispora^ refers to the 3- septate ascospores and conidia.
Holotype: MFLU 11–0202
Saprobic on rotten dead bamboo culms. Sexual morph: Ascostromata 180–310 μm high, 470–730 μm diam., scattered to clustered, solitary to gregarious, immersed, sub-epidermal, visible as raised, black structures on the host surface, with flattened base, convex or dome-shaped to ampulliform, uni-loculate; sometimes forming pseudostroma, bi- to tri-loculate, glabrous, centrally ostiolate ascomata. Peridium 10–40 μm wide, thin- to thick-walled, of unequal thickness, slightly thick at the sides, poorly developed at the base, composed of several layers of brown to dark brown, pseudoparenchymatouscells interdispersed with host cells, with inner layers comprising several layers of hyaline textura angularis cells, outer layers comprising several layers of flattened, brown to dark brown textura angularis cells, coriaceous. Hamathecium dense, filamentous, 1–2 μm wide, distinctlyseptate, smooth-walled, cellular pseudoparaphyses, anastomosing at the apex, embedded in a hyaline gelatinous matrix. Asci (78–)80–100(−110) × 10–12(−14) μm (x = 95 × 11.1 μm, n = 30), 8-spored, bitunicate, fissitunicate, cylindrical to cylindri-clavate, short pedicellate, apically rounded, with well-developed ocular chamber. Ascospores (25–)26–30(−31) × 4–6 μm (x = 27.7 × 5.5 μm, n = 30),overlapping, uni- to bi-seriate, hyaline to pale brown, fusiform, with acute ends, 3-septate, rarely constricted at septa, smooth-walled, surrounded by an irregular mucilaginous sheath. Asexual morph: Coelomycetous, produced on bamboo pieces on WA after 2 months. Conidiomata 350–480 μm high, 420–700 μm diam., pycnidial, solitary to gregrarious, semi-immersed at the base, becoming superficial, visible as raised, black dots on colonies, eustromatic or sometimes pseudostromatic, irregularly shaped, uni- to multi-loculate, covered by vegetative hyphae, with indistinct ostioles. Wall of Conidiomata 17–60 μm wide, thin- to thick-walled, of unequal thickness, slightly thick at sides, composed of several layers, of dark brown to black, textura angularis to textura prismatica pseudoparenchymatous cells mixed with host cells. Conidiophores reduced to conidiogenous cells. Conidiogenous cells (9–)(10–)12–28(−32) × 1.5–3 μm (x = 18.8 × 2.2 μm, n = 30), holoblastic, determinate, discrete, cylindrical to irregularly-shaped, hyaline, with distinct periclinal thickening, smooth. Conidia (15–)18–20(−22) × 3–5 μm (x = 19.3 × 4.1 μm, n = 30), cylindrical to cylindric-clavate, narrow towards ends, apex rounded, with truncate base, initially 1-septate and hyaline, becoming 3-septate and brown at maturity, constricted at the septa, smooth, with guttules.
Culture characters: Colonies on PDA fast growing, 50– 60 mm diam. after 4 weeks at 25–30 °C, under 12 h light/ 12 h dark, irregular, medium dense to dense, flat, slightly raised, rough with lobate edge, fluffy to floccose, or velvety; white to cream at the margin, white-grey at the centre; reverse white to cream at the margin, pale yellowish to yellowish at middle, yellowish grey to dark grey at the center, slightly radiating outwards; forming grey to white tufts, with pycnidia and yellowish droplets surrounding the colonies.
Material examined: THAILAND, Mukdahan Province, Nongsung District, Wang Hai Village, on dead culms of bamboo, 13 April 2011, R. Phookamsak, RP0082 (MFLU11– 0202, holotype), ex-type living cultures, MFLUCC 11– 0166, KUMCC.
Notes: Bambusicola triseptatispora is similar to B. thailandica in having phragmosporous, fusiform, 3-septate ascospores. However, B. triseptatispora differs from B. thailandica by the colour of its ascospores, ascostromata and asexual morph. Bambusicola triseptatispora has phragmosporous, fusiform, pale brown, 3-septate, smooth ascospores with uni- to multi-loculate pseudoascostromata and phragmosporous, cylindric-clavate, brown, 3-septate conidia, whereas B. thailandica forms phragmosporous, fusiform, hyaline, ascospores slightly constricted at median septum, with scattered, uni-loculate ascostromata. The asexual morph of B. triseptatispora is similar to B. splendida. However, B. triseptatispora has smaller conidia and longer conidiogenous cells. Based on multi-gene phylogenetic analyses (Fig. 8), B. triseptatispora forms a robust clade with B. loculata, which is similar, but has multi-loculate ascomata and 1-septate ascospores (Dai et al. 2015).
FIG. 12 Bambusicola triseptatispora (MFLU 11–0202, holotype). a Appearance of ascostromata on host surface; b Vertical section through ascostromata; c, d Section through peridium; e Asci with pseudoparaphyses stained with congo red; f–h Asci; i–l Ascospores; m Ascospore stained with Indian ink; n, o Cultures characters (upper and lower sides); p Conidiomata produced on bamboo pieces on WA; q Section through pycnidia; r–t Conidiogenous cells attached with conidia; u–z Conidia; Scale bars: b, q = 200 μm, c–h, r, t = 20 μm, i–m, s, u–z = 10 μm