Fissuroma taiwanense Tennakoon, C.H. Kuo & K.D. Hyde, 2018

Tennakoon, Danushka S., Phookamsak, Rungtiwa, Kuo, Chang-Hsin, Goh, Teik K., Jeewon, Rajesh & Hyde, Kevin D., 2018, Morphological and phylogenetic evidence reveal Fissuroma taiwanense sp. nov. (Aigialaceae, Pleosporales) from Hedychium coronarium, Phytotaxa 338 (3), pp. 265-275 : 268-270

Fissuroma taiwanense Tennakoon, C.H. Kuo & K.D. Hyde , sp. nov.

Index Fungorum Number: IF553870; Facesoffungi number: FoF 03660, Fig.2

Etymology: — Named after Taiwan, where this fungus was collected.

Holotype:— F31005

Saprobic on dead stem of Hedychium coronarium J. Koenig. Sexual morph: Ascomata 850–1000 μm long, 120–130 μm high, 180–210 μm diam., dark brown, coriaceous, scattered to clustered, gregarious, unilocular, hemispherical, immersed beneath host epidermis, appearing as raised areas, retaining several layers of brown host cells within the upper peridium, with a central slit-like ostiole over almost the entire length. Peridium 36–50 μm wide at sides, 80–90 μm wide near ostiole, brown, thick-walled, of textura angularis, base and corners comprising a mixture of host and fungal cells. Hamathecium composed of dense, 1–1.5 μm wide, trabeculate, hyaline pseudoparaphyses, anastomosing at the apex, embedded in a gelatinous matrix. Asci (97–)100–120(–125) × (23.5–) 24–29(–30) μm (x = 110 × 26.5 μm, n = 30), 8-spored, bitunicate, fissitunicate, broadly cylindrical to obclavate, subsessile to short pedicellate, with obtuse pedicel, apically rounded, with well-developed, ocular chamber. Ascospores 52–56 × 8.5–10 μm (x = 53.5 × 9.4 μm, n = 30), overlapping, 1–3-seriate, fusiform, hyaline, smooth-walled, tapering to pointed apices, 1-septate, septum nearly median, constricted at the septum, straight to curved, surrounded by a thick distinctive sheath, 2.5–3 μm wide (in water mounted slide), spreading a mucilaginous sheath up to 14–16 μm (with Indian ink), club-shaped appendages at both ends, 8–12 μm long, 4.1–4.6 μm wide at base, 5.2–6.3 μm wide at middle, smooth-walled, with guttules. Asexual morph: Undetermined.

Culture characteristics: Colonies on PDA reaching 10 mm diameter after 2 weeks at 25–30 ° C, colonies medium dense, circular, convex, surface slightly rough with edge entire, effuse, velvety to hairy, margin well-defined, colony from above: light brown to yellowish at the margin, brown to dark greenish at the centre; reverse, light brown to yellowish at the margin, brown to black at the centre; mycelium light brown to greenish with tufting; not producing pigments in PDA.

Material examined:— Taiwan, Chiayi,Shihnong ForestArea,dead stems of Hedychium coronarium ( Zingiberaceae ), 25 June 2017, D. S. Tennakoon, DTW 014 ( F 31005, holotype, MFLU 18-0067, paratype), ex-living culture, FU 30861, DTW 001 ( F 31004, isotype), living culture, FU 30862).

Notes:— Fissuroma taiwanense resembles other species of Fissuroma in having hemisphaerical, coriaceous ascomata, with slit-like ostioles, trabeculate pseudoparaphyses, and hyaline, fusiform, 1-septate ascospores ( Liu et al. 2011, Phookamsak et al. 2015, Wanasinghe et al. 2017). However, our novel species, F. taiwanense can be distinguished from all other Fissuroma species in having broadly cylindrical to obclavate asci (x = 110 × 26.5 μm) and broad ascospores (x = 53.5 × 9.4 μm) with distinctive club-shaped, long apical and basal appendages (8–12 μm). The phylogeny ( Fig. 1 ) indicates that F. taiwanense is a sister taxon to the type species, F. maculans (86% ML, 91 % MP, 1.00 % PP). Morphologically, it differs from F. maculans in having long apical and basal appendages, a spreading distinct thick mucilaginous sheath around the ascospores (in Indian ink), broad asci and ascospores and host occurrence ( Table 3). A comparison of the 538 nucleotides across the ITS (+ 5.8S) gene region of F. taiwanense and F. maculans ( MFLUCC 10-0886) shows 15 base pair differences. Major base pair differences were listed in Table 2.

Figures

FIGURE 1. RAxML tree based on a combined dataset of LSU, SSU and tef1-α partial sequences. Bootstrap support values for maximum likelihood (ML), maximum parsimony (MP) higher than 75 % and Bayesian posterior probabilities (BYPP) greater than 0.95 are given above each branch respectively. The new isolates are in red. Ex-type strains are in bold. The tree is rooted to Lophiotrema lignicola (Lophiotremataceae).

FIGURE 2. Fissuroma taiwanense (F31005) a Appearance of ascomata on host. b Close-up of ascomata. c Vertical section of ascoma. d Horizontal section of ascoma. e–f Sections of peridium. g Pseudoparaphyses. h–i Asci. j Ascus viewed with fluorescence microscopy. k–l Ascospores. m Ascospore with fluorescence immersion. n Germinated ascospore. o–p. Apical and basal appendages viewed with fluorescence microscopy. q Ascospore stained in Indian ink showing a mucilaginous sheath. r Colony from above. s Colony from below. Scale bars: c = 100 μm, d = 50 μm, e–f = 10 μm, g–j = 30 μm, k–m = 10 μm, n, q = 20 μm, o–p = 10 μm.