Diaporthe musigena Crous & R.G. Shivas, Persoonia 26: 119 (2011)

MycoBank number: MB 560160; Index Fungorum number: IF 560160; Facesoffungi number: FoF 10666; Fig. **

Saprobic on dead twigs attached to Magnolia champaca. Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata 70–90 μm high × 120–140 μm diam. ( = 84 × 130 µm, n = 10), pycnidial, dark brown, pyriform, immersed to semi-immersed, erumpent at maturity. Conidiomata wall 10–20 μm wide, composed of 4–7 layers of pale brown cells of textura angularis. Hamathecium aparaphysate. Conidiophores 10–20 × 1–2 μm, hyaline, cylindrical, unbranched, straight, smooth, densely aggregated. Conidiogenous cells 3–4 × 1–2 μm, phialidic, terminal, hyaline, cylindrical, slightly tapering towards the apex. Alpha conidia 6–8 × 2–3 ( = 7 × 2.4 µm, n = 30), hyaline, fusiform, aseptate, smooth, tapering towards both ends, straight to slightly curved.

Culture characteristics – Colonies on PDA reaching 25 mm diameter after 2 weeks at 25°C, colonies from above: circular, margin entire, slightly dense, surface smooth, pale brown at the margin, cream in the centre; reverse: pale brown at the margin, dark brown in the centre.

Material examined – THAILAND, Chiang Rai Province, dead twigs attached to Magnolia champaca (Magnoliaceae), 9 January 2019, N. I. de Silva, NI304 (MFLU 21-0212), living culture, MFLUCC 21-0182.

Known hosts and distribution – On necrotic leaf tissue of Musa sp. in Australia (Crous et al 2011).

GenBank numbers – ITS: OK393699, tub2: OK490916, tef1: OL439479, CAL: *******.

Notes – A new saprobic collection (MFLU 21-0212) isolated from dead twigs of Magnolia champaca shares similar characteristics with the type of pathogenic Diaporthe musigena (CBS 129519) associated with necrotic leaf tissue of Musa sp. in Australia, in having hyaline, fusiform, aseptate alpha conidia with smooth tapering ends. The new strain (6–8 × 2–3 μm) and the type D. musigena ((7–)8–10(–12) × (2–)2.5(–3) μm) has similar size range of alpha conidia (Crous et al. 2011). As morphological characters examined largely overlap with type D. musigena, we therefore report our collection as a new host record of D. musigena from Magnolia champaca in Thailand.

Figure ** Diaporthe musigena (MFLU 21-0212) a The specimen. b, c Appearance of conidiomata on the substrate. d, e Sections through conidioma. f Peridium. g, h Conidiogenous cells. i–k Alpha conidia. Scale bars: a, b = 500 μm, c = 100 μm, d, e = 50 μm, f–h = 10 μm, i–k = 5 μm.