Annulohypoxylon purpureonitens (Y. M. Ju & J. D. Rogers) Y. M. Ju, J. D. Rogers & H. M. Hsieh

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

Annulohypoxylon purpureonitens (Y. M. Ju & J. D. Rogers) Y. M. Ju, J. D. Rogers & H. M. Hsieh , Mycologia 97 (4): 861 (2005)

Fig. 8

Hypoxylon purpureonitens Y. M. Ju & J. D. Rogers 1996 . Basionym.

Description.

Saprobic on the dead wood of Sterculia tragacantha . Sexual morph: Ascostromata 2–10 mm long × 3–8 mm broad and 0.25–0.35 mm thick (x ̄ = 7.5 × 5.5 × 0.3 mm, n = 10), hemispherical, effused-pulvinate, solitary or clustered, shiny, surface black, carbonaceous. Ascomata 0.4–0.5 mm high × 0.3–0.4 mm diam. (x ̄ = 0.45 × 0.35 mm, n = 15), immersed in the stroma, subglobose to globose, black, ostioles papillate, encircled with a flattened truncatum-type disc 0.18–0.25 mm diam. (x ̄ = 0.2 mm, n = 10). Hamathecium 2.5–4.5 μm wide, comprising long, hyaline, unbranched, aseptate paraphyses. Asci 90–110 × 5–7 μm (x ̄ = 100 × 6.2 μm, n = 20), the spore-bearing parts 60–70 µm long with stipes 20–40 µm long, 6 - spored, unitunicate, cylindrical, with an apical ring not bluing in Melzer’s iodine reagent. Ascospores 7–9 × 3–6 μm (x ̄ = 8.5 × 4.4 μm, n = 40), uniseriate, one-celled, inequilaterally ellipsoidal, with narrowly rounded ends, hyaline when immature, becoming dark brown at maturity, guttules present at the immature stage, with straight, spore length germ slit. 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 2–2.5 cm diam. after seven days at 25 ° C, circular in shape, white at first, cottony, white color in the front view, dark brown or black in the middle, and brown at the margin in the reverse view.

Material examined.

Thailand • Chiang Rai, Phan District, Sai Khao, forest area near Wat Udom Waree , on decaying wood of Sterculia tragacantha ( Malvaceae ), 05 July 2024, Achala Rathnayaka, AA 30 ( MFLU 24-0527 ); living culture MFLUCC 24-0609 .

Known distribution.

Brazil (on an unidentified branch of a dicotyledonous tree) ( Pereira et al. 2009); Thailand (on rotten wood, Sterculia tragacantha ) ( Suwannasai et al. 2013; this study).

Notes.

According to the multi-gene phylogenetic analyses (ITS, LSU, β-tub, and rpb 2), our strain ( MFLUCC 24-0609 ) clustered with the ex-type strain of A. purpureonitens ( MFLUCC 14-1225 ) with 97 % ML bootstrap and 0.84 PP support (Fig. 3 ). Our fungal collection ( MFLUCC 24-0609 ) shows morphological characteristics similar to the holotype of A. purpureonitens ( WSP 71615 ), including effused-pulvinate ascostromata and unicellular, ellipsoid-inequilateral, brown ascospores with a straight, spore-length germ slit ( Pereira et al. 2009). In this study, we introduced our fungal collection as a new host record of A. purpureonitens on Sterculia tragacantha in Thailand.

Figures

Figure 3. Phylogram generated from ML analysis based on the combined dataset of ITS, LSU, β-tub, and rpb 2. The tree is rooted to Biscogniauxia petrensis (HKAS 102388). 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 8. Annulohypoxylon purpureonitens on the dead wood of Sterculia tragacantha (MFLU 24-0527, a new host record). a. Substrate; b, c. Appearance of ascostromata on host; d. Ostiolar discs in ascomata (indicated by arrows); e. Horizontal section through ascomata; f. Paraphyses; g – l. Asci; m. Apical apparatus (not staining in Melzer’s reagent); n – q. Ascospores (q: arrows indicate the germ slit); r Germinated ascospores; s, t Colony on the PDA (s upper, t lower). Scale bars: 5 mm (b); 500 μm (c, d); 200 μm (e); 20 μm (f – l); 5 μm (m – r).