Pyriformiascoma trilobatum
Pyriformiascoma trilobatum Daranag., Camporesi & K.D. Hyde, in Daranagama, Camporesi, Tian, Liu, Chamyuang, Stadler & Hyde, Fungal Diversity 73: 230 (2015)
Index Fungorum number: IF 809527; Facesofungi number: FoF 00329
Etymology: In reference to the characteristic tri-lobed apical apparatus.
Saprobic on wood, stems and twigs. Sexual morph: Ascomata immersed, mostly solitary, appearing as blackened, slightly raised, conical areas, with central black ostiolar dot, in cross section 250–300 × 300 μm (x̄ = 269.5 × 300 μm, n=10), obpyriform, with ostiolar canal comprising broadly rounded host cells, 20–30 × 20–25 μm (x̄ = 23.8 × 21.5 μm, n=10). Peridium 15–20 μm diam. (x̄ = 15.5 μm, n=10), with few cell layers, outwardly comprising dark brown cells of textura oblita and inwardly comprising hyaline cells of textura angularis. Paraphyses 2.5 μm diam. (x̄ = 2.5 μm, n=10), numerous, filamentous, septate. Asci 70–85 × 4.5–6 μm (x̄ = 82 × 5.5μm, n=30), 8-spored, unitunicate, cylindrical, short-pedicellate, apically rounded, with cytoplasm forming fork-like invagination below indistinct apical apparatus, J-, apical apparatus, 5–7 × 3–4 μm (x̄ = 5.7 × 3.5 μm, n = 30). Ascospores 15–18 × 4.5–6 μm (x̄ = 16.5 × 5.5 μm, n=40), overlapping uniseriate, inequilaterally oblong-ellipsoidal, dark brown, unicellular with a hyaline dwarf cell at base, 2–2.5 μm in length (x̄ = 2.2 μm, n=40), smooth-walled, larger cell olivaceous-green, lacking a germ slit. Asexual morph: Conidiophores up to 65–90 × 3.6–6 μm (x̄ = 87.5 × 5 μm, n=20), simple, pale brown, rarely branched, aseptate. Conidiogenous cells 18–22 × 6.2–6.5μm (x̄ = 19.5 × 6.4 μm, n=20), terminal, single, cylindrical, denticals present, if not smoothly curved. Conidia 13.5–17 μm in diam. (x̄ = 15.3 μm, n=20), light brown, globose, smooth.
Culture characteristics: Colonies on Difco OA plates at 25–27 °C reaching 9 cm edge of Petri-dish in 1 month, at first Citrine (13), felty, azonate, with diffuse margins, after 2 weeks become yellowish brown and isebelline and zonate; reverse turning yellow and dark brown, zonate, two types of mycelium present, thin mycelium and thick mycelium. Conidiophores emerge from the thick mycelium, which formed into hyphal aggregates that are melanised and thickened, usually light brown.
Material examined: ITALY, Province of Forlì-Cesena, Monte Riccio-Bagno di Romagna, on Cornus sp. (Cornaceae), 18 October 2013, E. Camporesi IT1483 (MFLU 14-0231, holotype), ex-type cultures, MFLUCC 14-0012=ICMP; Ibid, 18 October 2013, E. Camporesi IT1483 (PDD, isotype).
GenBan: ITS–KP297402, RPB2–KP340530, ß-tubulin– KP406613, LSU–KP340543
Notes: Pyriformiascoma trilobatum share characters with several Anthostomella species, such as, A. clypeata (De Not.) Sacc., A. rostrospora W.H. Hsieh et al. and A. nypicola K.D. Hyde et al., which have unicellular ascospores with a hyaline dwarf cell and a dark large cell, and lack a sheath or germ slit. Anthostomella clypeata differs from Pyriformiascoma trilobatum as it has a well-developed clypeus and globose ascomata, a peridium comprising elongate, angular cell layers, both inwardly and outwardly and asci with a J+, wedged-shaped, apical apparatus. Anthostomella rotrospora has globose asomata and asci with a wedged-shape, J+, apical apparatus and ascospores with a hyaline larger cell with an acute end at the upper part. The same olivaceous larger cell is present in A. nypicola, however it is different from the new taxon as A. nypicola has globose to subglobse ascomata with thick-walled layers,with compressed cells, and asci with a J+, wedged-shaped, apical apparatus. Three Anthostomella species discussed in Lu and Hyde (2000) have a uniseriate ascospore arrangement, while in Pyriformiascoma trilobatum the arrangement is biseriate. A comparison of morphological characters of the genera examined in this study is provided below.
Figure 1. Pyriformiascoma trilobatum (holotype) a. Habitat on wood b. Ascomata in wood c. Cross section of an ascoma d. Peridium e. Asci in Melzer’s reagent with J-, apical apparatus f. Immature ascus in water g. Semimature ascus in water h. Mature ascus in water i. Immature ascospore in water j, k. Mature ascospores in water (Note the hyaline dwarf cell). Scale bars: a, b =1000 μm, c, d =100 μm, e–k = 10 μm.
Figure 2. Pyriformiascoma trilobatum (culture from holotype) on OA after 14 days a. From above b. From below c. Oil droplets deposited on the mycelium masses d and e. Sporulating regions after 7 days and 14 days f–i. Development of conidiophores j. Conidiogenesis cell k, l. Conidiogenesis cells bearing conidia m, n. Conidia o.Different types of hyphae. Scale bars: f–o=20 μm.
Figure 3. Drawings of Pyriformiascoma trilobatum (from holotype) a. Apical apparatus b, c. Conidiogenesis structures d. Conidiogenesis cells bearing conidia. Scale bars: a = 5 μm, b–d = 20 μm
References:
Daranagama DA, Camporesi E, Tian Q, Liu X et al. 2015 – Anthostomella is polyphyletic comprising several genera in Xylariaceae. Fungal Diversity 73, 203–38.
Lu BS, Hyde KD 2000b – A world monograph of Anthostomella. Fungal Diversity Research Series 4. Fungal Divers:1–376.
Last Update: 07 September 2021