Ophiosphaerella taiwanensis Tennakoon, C.H. Kuo & K.D. Hyde, 2020

Tennakoon, Danushka S., Thambugala, Kasun M., Wanasinghe, Dhanushka N., Gentekaki, Eleni, Promputtha, Itthayakorn, Kuo, Chang-Hsin & Hyde, Kevin D., 2020, Additions to Phaeosphaeriaceae (Pleosporales): Elongaticollum gen. nov., Ophiosphaerella taiwanensis sp. nov., Phaeosphaeriopsis beaucarneae sp. nov. and a new host record of Neosetophoma poaceicola from Musaceae, MycoKeys 70, pp. 59-88 : 59

Ophiosphaerella taiwanensis Tennakoon, C.H. Kuo & K.D. Hyde sp. nov. Figure 3

Etymology.

Named after Taiwan, where this fungus was collected.

Holotype.

MFLU 18-2534.

Diagnosis.

Saprobic on dead leaf of Agave tequilana F.A.C. Weber ( Asparagaceae ). Sexual morph: Ascomata 270-310 μm high, 220-260 μm diam., solitary, scattered, immersed to slightly erumpent through host tissue with papilla, visible as raised, small black dots in host surface, globose to subglobose, uniloculate, glabrous, dark brown to black, ostiole central, periphysate. Peridium 20-25 μm wide, thick-walled, of equal thickness, composed of 6-7 layers of small, flattened, brown to dark brown pseudoparenchymatous cells, hyaline towards the inside, arranged in a textura angularis, fusing and indistinguishable from the host tissues. Hamathecium of 1.5-2.5 µm wide, cellular, septate, rarely branching, pseudoparaphyses, anastomosing mostly above the asci and embedded in a mucilaginous matrix. Asci 115-140 × 8.5-10 μm (x̄ = 121.6 × 9.2 μm, n = 20), 8-spored, bitunicate, fissitunicate, cylindrical to cylindric-clavate, short pedicellate, apically rounded, with a well-developed ocular chamber. Ascospores 110-132 × 2.2-2.7 μm (x̄ = 117.2 × 2.4 μm, n = 20), fasciculate, parallel, scolecosporous, filiform, 12-13-septate, narrowing towards ends, pale brown to brown, smooth-walled. Asexual morph: Undetermined.

Culture characteristics.

Colonies on PDA reaching 25 mm diameter after 3 weeks at 20-25 °C, colonies medium sparse, circular, raised, surface slightly rough with entire edge, margin well-defined, colony from above: gray to light brown at the margin, gray to cream at the center; reverse, gray to light brown at the margin, dark brown to black at the center; mycelium whitish gray with tufting; not producing pigments in PDA.

Material examined.

Taiwan, Chiayi, Fanlu Township area, Dahu Forest, dead leaf of Agave tequilana F.A.C. Weber ( Asparagaceae ), 15 August 2018 (23°27.520'N, 120°36.310'E), D.S. Tennakoon, TLF016 (MFLU 18-2534, holotype); ibid. (NCYU19-0131, isotype), ex-type living culture, NCYUCC 19-0152.

Notes.

The scolecosporous specimen was collected from dead leaves of Agave tequilana ( Asparagaceae ) in Taiwan. The multi-gene phylogenetic analysis (Figure 1 ) shows our strain ( Ophiosphaerella taiwanensis , NCYUCC 19-0152), cluster with other Ophiosphaerella species, in particular with close affinity to Ophiosphaerella agrostidis with high bootstrap support (88% ML, 70% MP, 0.99 BYPP, Figure 1 ). Morphological characters of our collection (NCYUCC 19-0152) differ from Ophiosphaerella agrostidis in having periphyses in the ostiole, 12-13 septate ascospores and host occurrence ( Asparagaceae ). Ophiosphaerella agrostidis was introduced by Câmara et al. (2000) on Agrostis palustris ( Poaceae ), and is lacking periphyses, comprises 15-septate ascospores ( Phookamsak et al. 2014). A comparison of the 619 nucleotides across the tef1 -α gene region of Ophiosphaerella taiwanensis and O. agrostidis (MFLUCC 11-0152) reveals 17 base pair differences (2.74%).

Figures

Figure 1. RAxML tree inferred from combined dataset of ITS, LSU, SSU and tef 1 - α partial sequences of 168 strains of Phaeosphaeriaceae. Bootstrap support values for maximum likelihood (ML), maximum parsimony (MP) values ≥ 70 %, and Bayesian posterior probabilities (BYPP) ≥ 0.95 are given above each branch respectively. The new species are highlighted in red, and the new record in green. Ex-type strains are in bold. The tree is rooted by Leptosphaeria doliolum (CBS 505.75) and Paraleptosphaeria dryadis (CBS 643.86).

Figure 3. Ophiosphaerella taiwanensis (MFLU 18 - 2534, holotype) a, b appearance of ascomata on host c close-up of ascomata d vertical section through ascoma e apex of ascoma f peridium g pseudoparaphyses h-j asci k, l ascospores m germinated ascospore in PDA n colony from above o colony from below. Scale bars: 100 µm (d, e), 15 µm (f), 50 µm (g-m).