Halorosellinia xylocarpi Dayar & K. D. Hyde

Rathnayaka, Achala R., Chethana, K. W. Thilini, Manowong, Areerat, Bhagya, Amuhenage T., Win, Hsan, Tun, Zaw L., Mapook, Ausana & Hyde, Kevin D., 2025, Taxonomy, phylogeny, and bioactive potential of Xylariales (Sordariomycetes, Ascomycota) from Thailand: novel species discovery, new host and geographical records, and antibacterial properties, MycoKeys 120, pp. 35-117 : 35-117

Halorosellinia xylocarpi Dayar & K. D. Hyde , Mycosphere 11 (1): 158 (2020)

Fig. 11

Description.

Saprobic on decaying submerged wood of Arecaceae sp. Sexual morph: Pseudostromata 0.6–1.0 × 0.5–0.8 mm (x ̄ = 0.8 × 0.6 mm, n = 5), superficial, pulvinate to hemispherical, in clusters of uni-peritheciate pseudostromata, surface black, carbonaceous, lacking ascomatal projections. Ascomata 0.3–0.34 × 0.34–0.36 mm (x ̄ = 0.33 × 0.35 mm, n = 5), superficial, globose or subglobose to hemispherical, black, ostioles papillate. Peridium 25–38 μm wide, consists of 6–7 layers of brown to dark brown textura angularis cells. Paraphyses 4–8 μm wide, hyaline, abundant, persistent, unbranched, septate. Asci 85–115 × 9–17 μm (x ̄ = 97 × 12 μm, n = 20), 8 - spored, unitunicate, cylindrical, long pedicellate, with J +, cylindrical apical ring. Ascospores 13–17 × 7–9 μm (x ̄ = 15 × 8 μm, n = 30), overlapping 1–2 - seriate, hyaline, becoming opaque green and dark brown when mature, more or less equilaterally ellipsoid, straight, both ends often pointed, 1 - celled, guttulate, without appendages, a spore length germ slit on the ventral side, straight. Asexual morph: Undetermined.

Culture characteristics.

Ascospores germinated on the PDA within 24 hours at 25 ° C. Germ tubes are produced from one side of the ascospore. Colonies on the PDA at 25–28 ° C, reaching 6 cm in seven days, circular in shape, zonate with diffused margins, white color in front view, and pale yellow in reverse view.

Material examined.

Thailand • Chang Wat Prachuap Khiri Khan Province, Pran Buri District, Pran Buri riverbank , 26 February 2023, Tharindu Bhagya, on decaying submerged wood of Arecaceae sp., TB ( MFLU 24-0536 ), living culture, MFLUCC 25-0025 .

Known distribution and hosts.

Thailand (submerged wood of Xylocarpus sp. , Rhizophora sp. , and submerged wood of Arecaceae sp.) ( Dayarathne et al. 2020 b; this study)

Notes.

Morphologically, our collection ( MFLU 24-0536 / MFLUCC 25 - 0025 ) resembles the holotype of H. xylocarpi ( MFLU 18-0545 ) in having superficial, carbonaceous, uni-perithecial pseudostromata; 8 - spored, cylindrical, unitunicate, long-pedicellate asci with a J +, cylindrical apical ring; and dark brown, unicellular, ellipsoid, straight ascospores with both ends often pointed and a straight germ slit on the ventral side along the spore length ( Dayarathne et al. 2020 b). However, asci (85–115 × 9–17 μm vs. 126–135 × 20–28 μm) and ascospores (13–17 × 7–9 μm vs. 20–26 × 10–14 μm) of our collection ( MFLUCC 25-0025 ) are smaller than the holotype ( Dayarathne et al. 2020 b). According to multi-gene phylogeny (ITS, rpb 2, and β-tub), our strains ( MFLU 24-0536 and MFLUCC 25-0025 ) cluster with the ex-type strain of H. xylocarpi ( MFLU 18-0545 ) with 100 % ML bootstrap and 1.00 PP support (Fig. 10 ). Considering the morpho-molecular evidence, we conclude that our collection is a new host record on decaying submerged wood of Arecaceae sp. in Thailand.

Figures

Figure 10. Phylogram generated from ML analysis based on the combined dataset of ITS, rpb 2, and β-tub. The tree is rooted to Hypoxylon fragiforme (HAST 383 and MUCL 51264). Bootstrap support values for ML ≥ 70 % and Bayesian posterior probabilities (PP) ≥ 0.90 are noted at the nodes. Strain numbers are noted after the species names. Strains isolated in this study are represented in blue, and type strains are in bold.

Figure 11. Halorosellinia xylocarpi on decaying submerged wood of Arecaceae sp. (MFLU 24-0536, a new host record). a. Substrate; b. Appearance of an ascoma on the host; c. A horizontal section through an ascoma; d. Peridium; e. Paraphyses; f – k. Asci; l, m. Apical apparatus stained blue with Melzer’s reagent; n – s. Ascospores (r: arrow shows the germ slit on the ventral side); t A germinated ascospore; u, v Colony on the PDA (u upper, v lower). Scale bars: 100 μm (b, c); 20 μm (d – k); 10 μm (l – t).