Neosetophoma poaceicola Goonas., Thambug. & K.D. Hyde. Mycosphere 8: 742 (2017)

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

Neosetophoma poaceicola Goonas., Thambug. & K.D. Hyde. Mycosphere 8: 742 (2017) Figure 6

Diagnosis.

Saprobic on dead leaf petioles of Musa acuminata Colla ( Musaceae ). Sexual morph: Ascomata 70-100 μm high, 90-130 μm diam., solitary, gregarious, coriaceous, immersed to semi-immersed, slightly raised, visible as black spots on host surface, uni-loculate, dark brown to black, globose to ovoid. Peridium 15-20 μm wide, thick-walled, of equal thickness, composed of several layers of dark brown to brown, pseudoparenchymatous cells of textura angularis. Hamathecium of 1-2 µm wide, cellular, rarely branching, pseudoparaphyses, anastomosing mostly above the asci and embedded in a mucilaginous matrix. Asci 60-80 × 7-8 μm (x̄ = 70.6 × 7.6 μm, n = 30), 8-spored, bitunicate, fissitunicate, cylindric-clavate with a short, rounded pedicel, apically rounded. Ascospores 20-30 × 3-4 μm (x̄ = 25.5 × 3.7 μm, n = 40), overlapping 1-2-seriate, hyaline, fusiform, with acute ends, 1-septate, 3-4 eu-septate, cell near the septum slightly larger, slightly constricted at the septum, straight to curved, smooth-walled, guttulate. Asexual morph: Undetermined.

Culture characteristics.

Colonies on PDA reaching 30 mm diameter after 3 weeks at 20-25 °C, colonies medium sparse, circular, flat, surface slightly rough with entire edge, margin well-defined, colony from above: yellow to light brown at the margin, brown at the center; reverse, yellow to light brown at the margin, dark brown at the center; mycelium light brown to whitish grey with tufting; not producing pigments in PDA.

Material examined.

Taiwan, Chiayi, Fanlu Township area, Dahu Forest, dead leaf petiole of Musa acuminata Colla ( Musaceae ), 21 July 2018 (23°27.530'N, 120°36.340'E), D.S. Tennakoon, SV049 (MFLU 18-2597, new host record), living culture, MFLUCC 18-1632, NCYUCC 19-0119.

Notes.

As morphological characters (immersed to semi-immersed ascomata, cylindric-clavate, apically rounded asci with short rounded pedicel and hyaline, fusiform, 1-septate ascospores) largely overlap with those of Neosetophoma poaceicola (MFLUCC 16-0886), we report our collection (MFLUCC 18-1632) as a new host record of N. poaceicola from dead leaves of Musa acuminata ( Musaceae ) in Taiwan. Combined multi-gene (LSU, SSU, ITS and tef1 -α) based phylogenies also showed that our collection clustered with Neosetophoma poaceicola (MFLUCC 16-0886), with high bootstrap support (100% ML, 100% MP, 1.00 BYPP, Figure 1 ). Neosetophoma poaceicola was introduced by Thambugala et al. (2017) from dead leaves of grass species in Thailand. However, our collection slightly differs from Neosetophoma poaceicola (MFLUCC 16-0886) in having comparatively slightly larger ascospores (20-30 × 3-4 μm, versus 18.5-22.5 × 3.5-5 μm).

Neosetophoma species have been recorded from various host families, viz. Brassicaceae , Caprifoliaceae , Iridaceae , Malvaceae , Ranunculaceae , Salicaceae , but most are reported from Poaceae ( Phookamsak et al. 2014; Karunarathna et al. 2017; Tibpromma et al. 2017, Wanasinghe et al. 2018; Marin-Felix et al. 2019). Interestingly, this is the first Neosetophoma species record (MFLU 18-2597) from the plant family Musaceae .

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 6. Neosetophoma poaceicola (MFLU 18 - 2597, new host record) a appearance of ascomata on host b close up of ascomata c vertical section through ascoma d peridium e pseudoparaphyses f-h asci i-k ascospores l germinated ascospore in PDA m colony from above n colony from below. Scale bars: 50 µm (c), 20 µm (d), 30 µm (e-h), 15 µm (i-l).