Allodiatrype trigemina Hai. X. Ma & M.K. Peng, 2021

Peng, Ming-Kai, Zhang, Bo, Qu, Zhi, Li, Yu & Ma, Hai-Xia, 2021, New record genus and a new species of Allodiatrype from China based on morphological and molecular characters, Phytotaxa 500 (4), pp. 275-284 : 279-281

Allodiatrype trigemina Hai. X. Ma & M.K. Peng , sp. nov. ( Fig. 2 )

MycoBank: MB837500

Etymology:—Referring to the Y-shaped or trigeminal-shaped ostiolar surface.

Holotype:— CHINA. Yunnan Province, Pu-er City, Taiyang River National Forest Park, alt. 1360 m, on decayed wood in evergreen forest with broadleaved trees, 18 October 2014, Ma Hai X., Q2 (FCATAS841).

Sexual morph: — Stromata 0.81–3.23 mm long × 0.61–1.72 mm wide (x = 1.5 × 1 mm, n = 45), 0.7–1.2 mm thick. Stromata scattered or aggregated on the host, superficial, irregular, black, with 5–7 ascomata immersed in a single stroma, with Y-shaped or trigeminal-shaped ostioles appearing on the surface of the stroma, sometimes cruciateshaped. Consists of a dark brown or black outer layer, small, tightly packed parenchymal cells and yellowish to green, loosely packed inner layer. Ascomata 308–680 µm high, 157–376 µm diam. (x = 473 × 259 µm, n = 30), immersed in the stroma, perithecial, globose to subglobose, smooth inner wall, short ostiolar necks. Paraphyses hyaline. Asci (including stalks), 62–96 × 4–7 µm (x = 76 × 6 µm, n = 30), 8 spores, unitunicate with long stalks, the spore-bearing part about 16–43 × 6–12 μm, the spores are arranged tightly. J+ in Melzer’s reagent with or without KOH pretreatment. Ascospores (5.5–)6–8(–9.2) × (1.5–)2.1–2.3(–2.5) µm (x = 7.6 × 2.1 µm, n = 48), aseptate, smooth-walled, ellipsoidal to cylindrical, multi-seriate to overlapping, arranged at the tip of the asci, colorless and transparent, unicellular with small fat globules at the end.

Specimen examined:— CHINA. Yunnan Province, Pu-er City, Taiyang River National Forest Park, alt. 1350 m, on decayed wood in evergreen forest with broadleaved trees, 18 October 2014, Ma Hai X., A2 (FCATAS842) .

Notes:

Allodiatrype trigemina is a member of the new genus Allodiatrype , characterized by having 1–10 Ascomata immersed in a stroma, with or without the black stromatic zone, ( Konta et al. 2020). Konta et al. (2020) described three new species, A. arengae Konta & K.D. Hyde , A. elaeidicola Konta & K.D. Hyde and A. elaeidis Konta & K.D. Hyde , and a new combination A. thailandica (R.H. Perera, Jian K. Liu & K.D. Hyde) Konta & K.D. Hyde of the genus from palms ( Arecaceae ). The Chinese collections are on the unknown decayed wood and have Y-shaped or trigeminalshaped, or cruciate-shaped ostiolar appearing on the stroma’s surface ( Fig. 2d Marked with arrows). Morphologically, A. trigemina is similar to A. arengae in lacking a black stromatic band and having yellow inner cells in the stromata, asci are similar to A.arengae , but the latter has umbilicate ostiolar appearing as black spots with ring-like structure and yellowish to light-brown, slightly larger ascospores (6–)7–10(−12) × 2–3 μm (x = 10 × 2 μm) ( Konta et al. 2020). Phylogenetically, the new species A. trigemina groups (FCATAS841, FCATAS842) with high bootstrap support within the genus Allodiatrype (95% ML, 0.99 BYPP). A. trigemina is distinct from its sister species A. elaeidicola , A. elaeidis , and A. arengae with high statistical support (96% ML) ( Fig. 1 ). however, morphologically, the latter differs from the Chinese materials by its yellowish inner layer, pale brown, opening ostiolar appearing as black spots, smaller ascospores 3.8–6.9 × 1–1.4 μm (x = 5.4 × 1.2 μm) ( Li et al. 2016).

A comparison of SSU, ITS, TUB2 nucleotides to the Allodiatrype species , the type species A. arengae phylogenetically differs from our new taxon in 2.65% (16/602 bp) base pair differences present in ITS gene; TUB2, 3.15% (45/1425 bp); SSU, 1.63% (17/1040 bp). A. elaeidicola differs from new taxon in 3.70% (22/593 bp) in ITS gene; SSU, 1.25% (13/1036bp) and 2.80% (40/1426bp) in TUB2 sequence data.

Comparisons with other species in the genus Allodiatrype are shown in Table 3. Allodiatrype trigemina shares similar morphological characteristics with the type species A. arengae , but differs in having Y-shaped or trigeminalshaped, or cruciate-shaped ostiolar appearing on the stroma’s surface.

Notes –‘-’ do not have sequence; base pair differences included gaps.

Figures

FIGURE 1. Phylogeny of Diatrypaceae inferred from ITS-SSU-TUB2 sequences. Topology is from RaxML analysis with maximum likelihood bootstrap values (≥75 former) and Bayesian posterior probability values (≥0.95, latter) shown along the branches. Different genera are indicated as coloured blocks. The new species is set in bold. Scale bar: 0.1 nucleotide substitutions per site. Branches with 100% ML and 1.00 BYPP are shown with a blue dot.

FIGURE 2 Allodiatrype trigemina (FCATAS841, Holotype). a, c Stromata on host substrate. b Cross section of stroma. d Close up of stromata surface, showing ostiolar opening appearing with Y-shaped or trigeminal-shaped structure.) e–g Vertical section of stroma, showing perithecia. h–j Asci. k–m Ascospores. n Paraphyses. Bars: a–g = 500 μm, h–j = 20 μm, n = 10 μm, k–m = 5 μm.