Pestalotiopsis guangxiensis N. Jiang, in Jiang, Voglmayr, Xue, Piao & Li, Microbiology Spectrum: 10.1128/spectrum.03272-22, 14 (2022)
Index Fungorum number: IF 841311; MycoBank number: MB 841311; Facesoffungi number: FoF 11695;
Etymology – named after the collection site of the type specimen, Guangxi Zhuang Autonomous Region.
Pathogenic to host leaves. Asexual state: Conidiomata in culture sporodochial, aggregated or solitary, erumpent, pulvinate, black, 350–800 μm diam., exuding black conidial masses. Conidiophores indistinct, usually reduced to conidiogenous cells. Conidiogenous cells hyaline, smooth, cylindrical to subcylindrical, annelidic, 8.5–17.5 × 2–5 μm, mean ± SD = 11.4 ± 2.7 × 3.1 ± 1.3 μm. Conidia fusoid, straight or slightly curved, 4-septate, smooth, slightly constricted at the septa, (17.5–)18–20.5(–21) × (7.5–)8–9(–9.5) μm, mean ± SD = 19.2 ± 1.2 × 8.3 ± 0.5 μm (n = 50), L/W = 1.9–2.6; basal cell obconic with a truncate base, thin-walled, hyaline, 2.5–4.5 μm; median cells 3, trapezoid or subcylindrical, concolourous, brown, thick-walled, the first median cell from base 4–4.5 μm long, the second cell 4–5(–5.5) μm long, the third cell 4–5 μm long, together (12–)12.5–13.5(–14) μm long; apical cell conic with an acute apex, thin-walled, hyaline, (2–)2.5–3(–3.5) μm long; basal appendage unbranched, tubular, centric, straight, (3–)3.5–4(–4.5) μm long, mean ± SD = 4 ± 0.5 μm; apical appendages 2–3, unbranched, tubular, centric, straight or slightly bent, (14–)15–18.5(–19) μm long, mean ± SD = 16.8 ± 1.9 μm. Sexual morph unknown.
Culture characters – Colonies on MEA flat, spreading, with flocculent aerial mycelium forming radially folded surface and undulate edge, isabelline, reaching a 55-mm diameter after 10 days at 25°C, producing yellow droplet, sterile; on PDA, flat, spreading, with flocculent aerial mycelium and crenate edge, white to fawn, reaching a 65-mm diameter after 10 days at 25°C, forming black conidiomata with black conidial masses.
Material examined – China, Guangxi Zhuang Autonomous Region, Nanning City, Qingxiushan District, Qingxiushan Park, on diseased leaves of Quercus griffithii, 4 December 2019, Dan-ran Bian (holotype CAF 800023; ex-holotype culture CFCC 54308); ibid., CFCC 54300.
Distribution – China
Sequence data – ITS: OK339737 (ITS1/ITS4); tef1: OK358498 (EF1-728F/EF2); tub2: OK358513 (Bt2a/Bt2b)
Notes – Two isolates of P. guangxiensis from Quercus griffithii formed a well-supported clade phylogenetically close to P. disseminata (Fig. 1). P. guangxiensis can be distinguished from P. disseminata by wider conidia (7.5 to 9.5 μm in P. guangxiensis versus 6.5 to 8 μm in P. disseminata) (21, 23). Additionally, P. guangxiensis differs from P. disseminata by sequence data (nucleotide differences: in the ITS, 4/506 [0.8%], 1 insertion; in tef1, 7/471 [1.49%], 6 insertions; in tub2, 1 to 3/406 [0.25 to 0.74%]).
Fig. 12. Morphology of Pestalotiopsis guangxiensis (CFCC 54308). A. Colony on PDA after 10 d at 25 °C; B. Colony on MEA after 10 d at 25 °C; C. Conidioma formed on PDA; D, E. conidiogenous cells giving rise to conidia; F, G. conidia. — Scale bars: C = 500 μm; D–G = 10 μm.