Paraeutypella citricola
Paraeutypella citricola (Speg.) L.S. Dissan., Wijayaw., J.C. Kang & K.D. Hyde, in Dissanayake, Wijayawardene, Dayarathne, Samarakoon & Dai, Biodivers. Data J. 9: e63864, 14 (2021)
Index Fungorum number: IF 558003 Facesoffungi number: FoF 09150
Saprobic on a dead branch of Swietenia macrophylla. Sexual morph: Stromata immersed in the bark of dead branches, erumpent, aggregated, circular to irregular in shape, superficial, carbonaceous. Endostroma white to light yellow. Ostiole opening separately, papillate or apapillate, central. Ascomata 840–880 μm high × 430–455 μm diam. (x̄ = 867 × 446 µm, n = 10), perithecial, with groups of 5–10 perithecia arranged in a valsoid configuration, black, subglobose, clustered, immersed in ascostroma with an ostiolar neck. Necks 220–265 μm long (x̄ = 248 µm, n = 10), papillate, central ostiolar canal filled with paraphyses. Peridium 25–48 μm wide, composed of two layers of textura angularis to textura prismatica; inner layer cells hyaline, outer layer cells brown to dark brown. Hamathecium 3–5 μm wide (x̄ = 4 µm, n = 15) comprises hyaline, long, narrow, unbranched, aseptate, guttulate cells, paraphyses arising from the base of perithecia. Asci 56–94 × 5–7 μm (x̄ = 67 × 6.4 μm, n = 20), 8-spored, unitunicate, thin-walled, clavate to cylindrical clavate, long pedicellate (35–55 μm), J- apical ring. Ascospores 7–9 × 2–3 μm (x̄ = 8 × 2.4 μm, n = 40), overlapping 2–3 seriate, allantoid, hyaline to light brown, smooth, aseptate, usually with small guttules. Asexual morph: Undetermined.
Culture characteristics: Ascospores are 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 3–5 cm in five days, medium dense, circular to slightly irregular, cottony, white color in the front view, and pale yellow in the reverse view.
Material examined: Thailand Chiang Rai, Nang Lae village, on a decaying branch of Swietenia macrophylla (Meliaceae), 08 April 2024, Achala Rathnayaka, AA16 (MFLU 24-0535); living culture, MFLUCC 24-0614.
Notes: Based on the phylogenetic analyses, our collection (MFLUCC 24-0614) clustered with other strains of P. citricola (HKAS 13311 and HVGRF01) with 100% ML bootstrap and 1.00 PP support. Morphologically, our collection is similar to the holotype of P. citricola (HMAS 290660), which was collected from the dead twigs of Acerpalmatum in China (Dissanayake et al. 2021). Both specimens share similar morphological characteristics, including immersed, erumpent, aggregated, superficial, carbonaceous stromata; black, subglobose, clustered ascomata immersed in the ascostroma with an ostiolar neck; 8-spored, unitunicate, clavate to cylindrical-clavate, long pedicellate asci with a J- apical ring; and allantoid, hyaline to light brown, aseptate ascospores, usually with small guttules (Dissanayake et al. 2021). However, our collection has a shorter neck (220–265 µm vs. 360–390 µm) and longer asci (56–94 µm vs. 70–75 µm) than the holotype (Dissanayake et al. 2021). Based on the morpho-molecular evidence, Paraeutypella citricola has been recorded from Thailand on various woody plants, including Hevea brasiliensis (Senwanna et al. 2021), Magnolia sp. (de Silva et al. 2022), and Microcos paniculata (Afshari et al. 2023). We identified our collection as a new host record of Paraeutypella citricola from Swietenia macrophylla from Thailand.
Figure 1. Phylogram generated from ML analysis based on the combined dataset of ITS and β-tub. The tree is rooted to Kretzschmaria deusta (CBS 826.72) and Xylariahy poxylon (CBS 122620). 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 presented in blue, and type strains are in bold.
Figure 2. Paraeutypella citricola on a dead branch of Swieteniamacrophylla (MFLU 24-0535, a new host record). a. Substrate; b. Stromata on the substrate; c. A cross-section of a stroma; d. A vertical section through the stroma shows ostioles and perithecia; e. Peridium; f. Paraphyses; g–k. Asci; l–o. Ascospores; p, q. Colony on the PDA (p upper, q lower). Scale bars: 5 mm (b); 1 mm (c); 200 μm (d); 20 μm (e–k); 5 μm (l–o).
References
- Rathnayaka AR, Chenthana KWT, Manowong A, Bhagya T, Win H, et al. (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, 35-117.
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