Diaporthe pterocarpi (S. Hughes) Udayanga, Xing Z. Liu & K.D. Hyde, Cryptog. Mycol. 33(3): 305 (2012)
MycoBank number: MB 801055; Index Fungorum number: IF 801055; Facesoffungi number: FoF 10667; Fig. **
Saprobic on dead twigs attached to Alstonia scholaris. Sexual morph: See Udayanga et al. (2012). Asexual morph: Coelomycetous. Conidiomata 130–150 μm high × 200–240 μm diam. ( = 142 × 220 µm, n = 10), pycnidial, dark brown, subglobose, immersed to semi-immersed, erumpent at maturity. Conidiomata wall 25–40 μm wide, composed of 5–8 layers of pale brown cells of textura angularis. Hamathecium aparaphysate. Conidiophores 25–30 × 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 6–9 × 2–4 ( = 7.5 × 2.6 µm, n = 30), hyaline, fusiform, aseptate, smooth, tapering towards both ends, straight to slightly curved, 1 or 2 guttules.
Culture characteristics – Colonies on PDA reaching 30 mm diameter after 2 weeks at 25°C, colonies from above: circular, margin filamentous, flat, slightly dense, velvety appearance, white; reverse: pale brown at the margin, dark brown in the centre.
Material examined – THAILAND, Chiang Rai Province, dead twigs attached to Alstonia scholaris (Apocynaceae), 25 April 2019, N. I. de Silva, AS17 (MFLU 21-0214), living culture, MFLUCC 21-0211, KUMCC 20-0094; AS3 (MFLU 21-0213), living culture, MFLUCC 21-0206, KUMCC 20-0085.
Known hosts and distribution – On leaves of Pterocarpus erinaceus in Togoland, leaves of Pterocarpus indicus in Thailand (Udayanga et al. 2012), on rotting fruits of Cucumis melo in Costa Rica (Broge et al. 2020).
GenBank numbers – (AS17) ITS: OK393700, tub2: OK490917, tef1: OL439480, CAL: *******; (AS3) ITS: OK393701, tef1: OL439481, CAL: *******.
Notes – Phylogenetic analyses based on concatenated ITS, tub2, tef1 and CAL sequence data depicted that our new collection of two strains of Diaporthe sp. (MFLUCC 21-0211 and MFLUCC 21-0206) cluster with D. pterocarpi (MFLUCC 10-0571) with 100% ML, **** BYPP statistical support. The new collection morphologically resembles the type D. pterocarpi in having overlapping size range of hyaline, fusiform, aseptate, smooth, guttulate alpha conidia. The type D. pterocarpi has (5-)6-7(-9) × (2-)2.5(-3) µm, biguttulate, rarely three guttulate alpha conidia (Udayanga et al. 2012) and the new collection has (6–9 × 2–4) µm, one or two guttulate alpha conidia. Hence, we include our new collection as a new host record of D. pterocarpi from dead twigs of Alstonia scholaris in Thailand.
Figure ** – Diaporthe pterocarpi (MFLU 21-0214) a–c Appearance of conidiomata on the substrate. d, e Sections through conidioma. f Peridium. g Conidiogenous cells. h, i Alpha conidia. Scale bars: b = 200 μm, c = 100 μm, d, e = 50 μm, f = 20 μm, g–i = 5 μm.