Annulohypoxylon spougei

Annulohypoxylon spougei Suwannasai, M.P. Martín, Phosri & Whalley, Persoonia 44: 353 (2020)

Index Fungorum number:  IF811164; Facesofungi number: FoF17295.

Saprobic on Antidesma madagascariense dead wood. Sexual morph: Ascostromata 1–3 cm long × 0.3–2 cm broad and 0.8–1.2 mm thick (x̄ = 2 × 1.4 × 1 mm, n = 10), hemispherical, effused-pulvinate, shiny, surface black, carbonaceous. Ascomata 0.25–0.6 mm high × 0.25–0.5 mm diam. (x̄ = 0.4 × 0.3 mm, n = 10), immersed in the stroma, subglobose to globose, black, ostioles papillate, encircled with a flattened, truncatum-type disc, 0.2–0.25 mm diam. (x̄ = 0.23 mm, n = 8). Hamathecium 3–5 μm wide, comprising long, hyaline, unbranched, septate paraphyses. Asci 27–42 × 2–3 μm (x̄ = 36 × 2 μm, n = 20), the spore-bearing parts 17–25 µm long with stipes 9–15 µm long, 8-spored, unitunicate, cylindrical, with an apical ring bluing in Melzer’s iodine reagent. Ascospores 7–9 × 3–4 μm (x̄ = 7.6 × 3.6 μm, n = 40), uniseriate, one-celled, inequilaterally ellipsoidal, with narrowly rounded ends, hyaline when immature, becoming brown at maturity, guttulate. Asexual morph: Undetermined.

Culture characters: Ascospores germinated on the PDA within 24 hours at 25 °C. Germ tubes are produced from both sides of the ascospore. Colonies on the PDA reaching 1.5–2.0 cm diam. after five days at 25 °C, circular in shape, white at first, cottony, white color in the front view, brown in the middle, and pale brown at the margin of the reverse view.

Material examined: Thailand Chiang Rai, near Ang Kep Nam Huai Luang Than Thong Reservoir, on decaying wood of Antidesma madagascariense (Phyllanthaceae), 05 July 2024, Achala Rathnayaka, AA24 (MFLU 24-0525); living culture MFLUCC 24-0607.

GenBank numbers: PQ860995 (LSU), PQ861000 (ITS), PQ878513 (rpb2)

Notes: According to the multi-gene phylogenetic analyses (ITS, LSU, β-tub, and rpb2), our strain (MFLUCC 24-0607) clustered with the ex-type strain of A. spougei (SWUF09-032) with 100% ML bootstrap and 1.00 PP support. Our fungal collection (MFLUCC 24-0607) exhibits morphological characteristics similar to the holotype of A. spougei (SWUFH099), including black, shiny carbonaceous ascostromata; 8-spored, unitunicate, cylindrical asci, with an apical ring that bluing in Melzer’s iodine reagent; and unicellular, inequilaterally ellipsoidal, brown ascospores (Crous et al. 2020). However, the ascospores of the A. spougei holotype show a straight germ slit along the full length of the spore, which is not observed in our isolate (MFLUCC 24-0607). Based on the morpho-molecular evidence, we identified our collection as a new host record of A. spougei on Antidesma madagascariense in Thailand.

Figure 1. Phylogram generated from ML analysis based on the combined dataset of ITS, LSU, β-tub, and rpb2. The tree is rooted to Biscogniauxia petrensis (HKAS102388). 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.