Phaeodothis mori Tennakoon, C.H. Kuo & K.D. Hyde, 2020

Tennakoon, Danushka S., Kuo, Chang-Hsin & Hyde, Kevin D., 2020, Multi-locus phylogeny reveals Phaeodothis mori sp. nov. (Didymosphaeriaceae, Pleosporales) from dead leaves of Morus australis, Phytotaxa 428 (3), pp. 241-254 : 247

Phaeodothis mori Tennakoon, C.H. Kuo & K.D. Hyde , sp. nov.

Index Fungorum Number: IF 556761; Facesoffungi number: FoF06268, FIGURE 2

Etymology: — Name reflects the host Morus australis , from which the holotype was collected.

Holotype: — MFLU 18-2612

Saprobic on decaying leaves of Morus australis Poir. Sexual morph: Ascomata 100–150 μm high, 80–130 μm diam., scattered to gregarious, immersed, papilla erumpent through host surface, coriaceous, dark brown to black, globose to subglobose, ostiolate. Peridium 15–20 μm wide, composing several layers of irregular cells arranged in a textura angularis , cells towards the inside hyaline, at the outside, light brown, thick-walled, somewhat flattened, fusing and indistinguishable from the host tissues. Hamathecium of 2–3 µm wide, cylindrical cellular, anastomosed, septate, unbranched, pseudoparaphyses. Asci (43.5–) 45–65 × (5.3–) 5.8–7 (–7.3) μm (x = 51.6 × 6.5 μm, n = 20), 8-spored, bitunicate, cylindrical to cylindric-clavate, short pedicellate with furcate to obtuse ends, apically rounded with an indistinct ocular chamber. Ascospores 10.5–12.5 × 3–4 μm (x = 11.5 × 3.6 μm, n = 25), overlapping biseriate, yellowish brown, subfusoid, septate at the centre, strongly constricted at the septum, straight or slightly curved, enlarged near the septum at the upper cell, surrounded by thin mucilaginous sheath, spreading up to 5–6 μm at both ends (with Indian ink), smooth-walled with guttules. Asexual morph: Undetermined.

Culture characteristics: — Colonies on PDA, 20–25 mm, diam. after 3 weeks, colonies medium dense, irregular, flat, slightly raised, surface smooth with crenate edge, fluffy to velvety with smooth aspects, zonate with different sector light brown to yellowish at the margin, dark brown at the middle, white to yellowish at centre; reverse light brown to yellowish at margin, dark brown to black at the centre, no pigmentation produced in media.

Material examined: — Taiwan, Chiayi, Fanlu Township area, Dahu forest, decaying leaves of Morus australis Poir. ( Moraceae ), 18 September 2018 (23°27.422’N 120°36.385’E), D.S. Tennakoon, TAP037-A (MFLU 18-2612, holotype), ex-type living culture, MFLUCC 18-1634; ibid. 20 September 2018 (23°27.405’N 120°36.568’E), TAP037- B (MFLU 19-2334, paratype), KUMCC19-0136.

Notes: — Fresh collections of Phaeodothis mori were made from different places in Dahu forest, Chiayi, Taiwan (23°27.422’N 120°36.385’E and 23°27.405’N 120°36.568’E). According to the multi-gene phylogenetic analyses (ITS, LSU, SSU and tef1-α), Phaeodothis mori nested with the Phaeodothis winteri (Niessl) Aptroot species (CBS 182.58 and AFTOL-ID 1590) in moderate bootstrap support (72% ML, 85% MP, 0.90 BYPP). The morphological characteristics of Phaeodothis mori fits with the generic morphology of Phaeodothis by having, immersed to nearly superficial ascomata, a sparse hamathecium consisting of cellular pseudoparaphyses, bitunicate, fissitunicate, cylindrical asci and fusiform, rounded end, 1-septate ascospores ( Aptroot 1995, Ariyawansa et al. 2014b). However, our novel species, Phaeodothis mori can be distinguished from P. winteri (a synonym of Didymosphaeria winteri Niessl ) in having smaller asci (45–65 × 5.8–7 μm), ascospores (10.5–12.5 × 3–4 μm) with mucilaginous sheath, whereas P. winteri has larger asci (60–80 × 10–12 μm) and ascospores (11–14 × 4.5–5 μm) without a mucilaginous sheath ( Niessl 1875). In addition, a comparison of the 851 nucleotides across the tef1-α gene region of Phaeodothis mori (MFLUCC 18-1634) and P. winteri (CBS 182.58) reveals 29 base pair differences (3.4%) and therefore provides further evidence to introduce P. mori as a new species as in the guidelines of Jeewon & Hyde (2016). Remarkably, this is the first Phaeodothis species record from Morus australis in Taiwan.

Figures

FIGURE 2. Phaeodothis mori (holotype, MFLU 18-2612) a, b. Appearance of ascomata on the host. c. Section of ascoma. d. Section of peridium. e. Pseudoparaphyses. f–i. Asci. j–l. Ascospores. m. Ascospores stained in Indian ink showing mucilaginous sheath. n. Germinated ascospore. o. Colony from below. p. Colony from above. Scale bars: c = 50 µm, d = 10 µm, e–i = 20 µm, j–n = 5 µm.