Apiospora mukdahanensis Monkai and Phookamsak, sp. nov.

MycoBank number: MB 559912; Index Fungorum number: IF 559912; Facesoffungi number: FoF 12853;

Description

Saprobic on dead leaves of bamboo. Sexual morph: Undetermined. Asexual morph: Colonies composed of rounded to ovoid, pulvinate, dark brown to black, 150–400 μm diam., immersed pycnidia. Mycelium basal, consists of smooth, brown to dark brown, branched septate hyphae. Conidiophore mother cells arising from the mycelial mat, ampulliform to lageniform, dark brown, smooth, (6–)7–8.5(–10.5) × (2.5–)3.5–4(–5.5) μm (= 8.5 ×4 μm, n = 12). Conidiophores polyblastic, cylindrical, pale brown, septate, with brown transversal septa, straight or flexuous. Conidiogenous cells polyblastic, smooth, hyaline to pale brown, ampulliform, cylindrical or lageniform, (6–)8.5–14(–20) × 1.5–2(–3) μm (= 11 ×2 μm, n = 15). Conidia brown to dark brown, smooth to slightly roughened, thick-walled, globose to subglobose, or irregularly round in face view, lenticular in side view (6–)–7.5(–8) × (5–)–6.5(–7) μm (= 7×6μm,n = 30), with a pale equatorial slit, and a central scar.

Material examined: THAILAND, Mukdahan Province, Tambon Phang Daeng, Amphoe Dong Luang, on dead leaves of bamboo, 24 July 2019, E. Yasanthika, E2B-4 (MFLU 22-0104, holotype), ex- type living culture MFLUCC 22-0056.

Distribution: Thailand

Sequence data: ITS: OP377735 (ITS4/ITS5); LSU: OP377742 (LROR/LR5); TEF1-α: OP381089 (728F/2218R)

Notes: Based on phylogenetic analysis, Apiospora mukdahanensis formed an independent lineage sister to A. mori with 100% ML and 1.00 PP support (Figure 1). Apiospora mukdahanensis is distinct from A. mori in having larger conidia (6–8.1 × 5.1–6.9 μm vs 4.5–5.5 × 4–5 μm) with slightly roughened wall (Tennakoon et al. 2021). Whereas, Arthrinium mori has smooth-walled conidia (Tennakoon et al. 2021). The new species is similar to Apiospora jatrophae in having similar sized conidia (6–8.1 × 5.1–6.9 μm vs 6.5–9.7 × 3.2–6.5 μm) (Sharma et al. 2014). However, Apiospora jatrophae differs from our new species in having thick multi-septate conidiophore with brown transverse septa and two types of conidia including smooth-walled, lenticular conidia and anomalous conidia (Sharma et al. 2014). The nucleotide comparison of ITS gene region showed 4.1% base pair differences (21/508 bp) between Apiospora mukdahanensis and Arthrinium mori (MFLUCC 20-0181 and NCYUCC 19-0340) and 9.6% base pair differences (48/498 bp) between A. mukdahanensis and A. jatrophae (AMH-9556, AMH-9557). However, the TEF1-α sequence data are not available for Arthrinium mori and Apiospora jatrophae to compare with our new species.

Figure 1. Apiospora mukdahanensis (MFLU22-0104) a. Conidiomata on host substrate b. Conidiophore mother cells c–e. Conidiophores, conidiogenous cells and conidia f–k. Conidia l–m. Colonies on PDA (l. from above, m. from below). Scale bars: a = 200 μm, b– k = 5 μm.