Tingoldiago hydei D.F. Bao, Z.L. Luo & H.Y. Su, 2020

Xu, Li, Bao, Dan-Feng, Luo, Zong-Long, Su, Xi-Jun, Shen, Hong-Wei & Su, Hong-Yan, 2020, Lignicolous freshwater ascomycota from Thailand: Phylogenetic and morphological characterisation of two new freshwater fungi: Tingoldiago hydei sp. nov. and T. clavata sp. nov. from Eastern Thailand, MycoKeys 65, pp. 119-138 : 119

Tingoldiago hydei D.F. Bao, Z.L. Luo & H.Y. Su sp. nov. Figure 2

Etymology.

Referring to Kevin D. Hyde for his contributions in fungal taxonomy.

Holotype.

Thailand, That Phanom, Nakhon Phanom, on submerged decaying wood, 13 November 2018, D.F. Bao, B-126 (MFLU 19-2842, holotype), ex-type living culture, MFLUCC 19-0499.

Description.

Saprobic on submerged decaying wood. Sexual morph: Ascomata 180-280 × 330-470 μm (x̄ = 400 × 420 μm, n = 10), immersed to semi-immersed, erumpentia, gregarious, scattered, depressed globose to conical with a flattened base, dark brown to black, as dark spots on host surface. Ostioles central, papillate, short, crest-like, dark brown. Peridium 33.5-50 μm wide, comprising 4-6 layers, brown to dark brown cells of textura anngularis. Hamathecium comprising 2-2.5 μm (n = 30) wide, numerous, branched, septate, hyaline, cellular pseudoparaphyses. Asci 95-164 × 18-22 μm (x̄ = 129 × 20 μm, n = 20), 8-spored, bitunicate, fissitunicate, cylindrical-clavate, rounded at apex, with a short pedicellate. Ascospores 37.5-42 × 7.5-9 μm (x̄ = 40 × 8 μm, n = 30), overlapping, 2-3-seriate, clavate with round ends, straight, uniseptate, deeply constricted at septum, with broad and short upper cells 17.5-20 × 7-8.7 μm (x̄ = 18.7 × 7.9 μm, n = 30), narrow and long lower cells 20.6-23.3 × 5.9-7.4 μm (x̄ = 21.9 × 6.7 μm, n = 30), tapering towards the end, with short appendages at the septum, hyaline, guttulate, smooth, surrounded by a fusiform gelatinous sheath. Asexual morph: Undetermined.

Culture characteristics.

Ascospores germinating on PDA within 24 hours. Colonies on MEA effuse, greyish-white to dark brown from above and below, reaching 3-4 cm diameter within 30 days at room temperature under natural light, composed of subhyaline to pale brown, septate, smooth hyphae.

Notes.

Phylogenetic analysis showed that Tingoldiago hydei is related to T. clavata ; however, they are in different lineages with significant support (99 ML/97 MP/1.00 PP, Figure 1 ). Tingoldiago hydei resembles T. clavata in having bitunicate, cylindrical-clavate asci and clavate, hyaline, uniseptate, ascospores with broad and short upper cells, narrow and long lower cells, tapering towards the end, surrounded by a gelatinous sheath. However, Tingoldiago hydei can be distinguished from T. clavata in having longer and narrower asci (95-164 × 18-22 vs. 110-148 × 20-27 μm) and smaller ascospores (37.5-42 × 7.5-9 vs. 48-51 × 7.5-8.5 μm). Moreover, ascospores of T. clavata have longer appendages at the septum, while the appendages of T. hydei are much shorter than T. hydei .

Tingoldiago clavata is similar to the type species, T. raminicola in having immersed to semi-immersed, depressed globose to conical ascomata with flattened base, bitunicate, fissitunicate, cylindrical-clavate asci and clavate, straight, uniseptate ascospores. However, T. clavata differs from T. raminicola in having longer asci (95-164 × 18-22 vs. 87.5-122 × 18.25-25 μm) and smaller ascospores (37.5-42 × 7.5-9 vs. 43.5-53 × 7.5-11 μm). Moreover, ascopores of T. clavata have short appendages at the septum while ascospores of T. raminicola lack appendages. In addition, we compared the base pairs of ITS regions between these two species and there were 25 base pairs without gaps (5.1%) differences. Therefore, we introduce our isolate as a new species based on both phylogeny and morphological characters.

Figures

Figure 1. Phylogenetic tree based on RAxML analyses of combined LSU, SSU, ITS and TEF 1 - α sequence data. Bootstrap support values for maximum likelihood (ML, black) and maximum parsimony (MP, red) higher than 75 % and Bayesian posterior probabilities (PP, black) greater than 0.95 are indicated above the nodes as MP / ML / PP. The ex-type strains are in bold and the newly obtained isolates are in red. The tree is rooted at Corynespora smithii (CABI 5649 b) and Corynespora cassiicola (CBS 100822).

Figure 2. Tingoldiago hydei (MFLU 19 - 2842, holotype). a-c Ascomata on wood d section of ascoma e peridium f, g pseudoparaphyses h ostiole i-l asci m-r ascospores s germinating ascospore t vegetative hyphae in culture u, v culture on PDA from surface and reverse. Scale bars: 50 μm (d, e, h), 20 μm (f-g, m-t), 30 μm (i-l).