Pestalotiopsis silvicola N. Jiang, in Jiang, Voglmayr, Xue, Piao & Li, Microbiology Spectrum: 10.1128/spectrum.03272-22, 22 (2022)

Index Fungorum number:IF 843391; MycoBank number: MB 843391; Facesoffungi number: FoF 11700;

Pathogenic to host leaves. Asexual state: Conidiomata in culture sporodochial, aggregated or solitary, erumpent, pulvinate, black, 50–450 μm diam., exuding black conidial masses. Conidiophores indistinct, usually reduced to conidiogenous cells. Conidiogenous cells hyaline, smooth, cylindrical to spherical, annelidic, 7.5–15 × 3–6 μm, mean ± SD = 10 ± 2.2 × 4 ± 1 μm. Conidia fusoid, straight or slightly curved, 4-septate, smooth, slightly constricted at the septa, (20–)21–24(–26) × (6–)6.5–7.5(–8.5) μm, mean ± SD = 22.5 ± 1.8 × 7 ± 0.7 μm (n = 50), L/W = 2.6–3.8; basal cell obconic with a truncate base, thin-walled, hyaline or pale brown, (2.5–)4–5.5(–6) μm; median cells 3, trapezoid or subcylindrical, concolourous, brown, thick-walled, the first median cell from base (4–)4.5–5 μm long, the second cell (3.5–)4–5(–6) μm long, the third cell 4–4.5(–5.5) μm long, together (12–)13–15(–16) μm long; apical cell conic with an acute apex, thin-walled, hyaline, (3–)4–5(–5.5) μm long; basal appendage 1–2, unbranched, tubular, centric, straight or slightly bent, (3.5–)4.5–7(–8) μm long, mean ± SD = 5.6 ± 1.1 μm; apical appendages 3, unbranched, tubular, centric, straight or bent, (12–)12.5–18.5(–22.5) μm long, mean ± SD = 15.6 ± 2.9 μm. Sexual morph unknown.

Culture characters – Colonies on MEA flat, spreading, with flocculent aerial mycelium forming concentric rings and entire edge, white, reaching a 60-mm diameter after 10 days at 25°C, forming black conidiomata with black conidial masses; on PDA, flat, spreading, with flocculent aerial mycelium and undulate edge, white, reaching a 60-mm diameter after 10 days at 25°C, forming black conidiomata with black conidial masses.

Material examined – China, Hainan Province, Changjiang Li Autonomous County, Bawangling National Forest Park, on diseased leaves of Cyclobalanopsis kerrii, 30 March 2019, Yong Li (holotype CAF 800048; ex-holotype culture CFCC 55296); ibid., CFCC 54915 and CFCC 57363.

Distribution – China

Sequence data – ITS: ON007032 (ITS1/ITS4); tef1: ON005049 (EF1-728F/EF2); tub2: ON005060 (Bt2a/Bt2b)

Notes – Three isolates of Pestalotiopsis silvicola from Cyclobalanopsis kerrii clustered into a distinct clade phylogenetically close to P. aggestorum, P. colombiensis, and P. jinchanghensis (Fig. 1). Morphologically, they share similar conidial characters. However, P. silvicola can be distinguished by sequence data (nucleotide differences from P. aggestorum: in the ITS, 1/505 [0.2%]; in tef1, 1/464 [0.22%]; in tub2, 1/441 [0.23%]; from P. colombiensis: in the ITS, 2/505 [0.4%]; in tef1, 8/464 [1.72%]; in tub2, 2/441 [0.45%]; from P. jinchanghensis: in the ITS, 1/500 [0.2%]; in tef1, 18/464 [3.88%], 4-bp insertions; in tub2, 1/441 [0.23%]).

Fig. 21. Morphology of Pestalotiopsis silvicola (CFCC 55296). A. Colony on PDA after 10 d at 25 °C; B. Colony on MEA after 10 d at 25 °C; C. Conidiomata formed on PDA; D, E. conidiogenous cells giving rise to conidia; F, G. conidia. — Scale bars: C = 300 μm; D–G = 10 μm.