Ophiocordyceps ovatospora H. Yu & D.X. Tang, 2022

Tang, Dexiang, Zhu, Juye, Luo, Lijun, Hou, Donghai, Wang, Zhiqin, Yang, Shidao & Yu, Hong, 2022, Ophiocordyceps ovatospora sp. nov. (Ophiocordycipitaceae, Hypocreales), pathogenic on termites from China, Phytotaxa 574 (1), pp. 105-117 : 111-113

Ophiocordyceps ovatospora H. Yu & D.X. Tang , sp. nov. Fig. 2

MycoBank: MB 845477

Etymology:— The epithet “ovatospora” refers to the ovate shape of conidia.

Holotype:— CHINA. Yunnan Province: Jiangcheng County, Jiahe Town, Jiangxi village , 23°13′50′′N, 101°19′13′′E, alt. 880 m, on a termite buried in soil, 15 June 2022, H. Yu ( YHH 2206001 , holotype; YFCC 22069183, ex-type culture). GenBank accession number: ITS = OP295105 , nrSSU = OP295110 , nrLSU = OP295113 , tef-1a = OP313801 , rpb1 = OP313803 , rpb2 = OP313805 .

Description:—Sexual morph: Stroma solitary, simple, cylindrical or clavate, glabrous, smooth, up to 11–16 cm (x̅ = 13 cm) long, 1–1.2 mm (x̅ = 1 mm) in diam., pale yellow, 9 cm emerging above leaf litter, 4 cm buried in the soil, fertile portion enlarging and generating toward the upper part of stromata, 30–35 × 1.2–1.4 mm (x̅ = 35 × 1.3 mm, n = 2), with perithecial apices. Perithecia pseudo-immersed, ovoid to pyriform, with short, exposed neck or rounded ostiole, (100–)110–140 × (75–)80–110 µm (x̅ = 125 × 95 µm, n = 30). Asci hyaline, filiform, 8-spored, (100–)110–125(–130) × (4–)5–7 µm (x̅ = 120 × 6 µm, n = 30); ascus caps prominent, capitate, 3–4 µm high (x̅ = 4 µm, n = 30) and 4–5 µm wide (x̅ = 4 µm, n = 30). Ascospores whole, hyaline, filiform, multiseptate, (100–)110–130 × 1–2 µm (x̅ = 120 × 2 µm, n = 20). Asexual morph: Hirsutella . Colonies on PDA, 55–60 mm diam. In 30 days at 25 °C, mycelium abundant, cushioned, slightly convex, pale to ivory. Stromata emerging after 10 days, ivory to pale yellow, up to 25–40 × 1–2 mm (x̅ = 30 × 1.5 mm, n = 30), reverse pale yellow to dark purple.Asexual conidiogenous structures were not observed from the stroma. Hyphae hyaline, septate, smooth-walled. Conidiogenous cells arising from aerial mycelium on PDA, monophialidic or rarely polyphialidic, hyaline, smooth, swollen towards the base, flask-shaped, tapering gradually into a thin neck, (10–)15–35(–40) µm (x̅ = 25 µm, n = 20) long, (2–)3–6 µm (x̅ = 5 µm, n = 20) wide at the base, 0.6–1.2 µm (x̅ = 0.8 µm, n = 20) wide at the apex. Conidia solitary, smooth-walled, hyaline, ovate, 3–5 × 3–4 µm (x̅ = 4 × 3.5 µm, n = 20).

Habitat:— On adult termites ( Termitidae ) buried in soil, emerging from the leaf litter in subtropical monsoon evergreen broad-leaf forest.

Known distribution:— China, Yunnan Province, Jiangcheng County, Jiahe Town , Jiangxi village.

Additional specimen examined:— CHINA. Yunnan Province: Jiangcheng County, Jiahe Town , Jiangxi village, 23°13′50′′N, 101°19′13′′E, alt. 880 m, on a termite buried in soil, 15 June 2022, D.X. Tang (YHH 2206002; YFCC 22069184, living culture). GenBank accession number: ITS = OP295106 , nrSSU = OP295111 , nrLSU = OP295114 , tef-1a = OP313802 , rpb1 = OP313804 .

Notes:— Ophiocordyceps ovatospora is characterized by solitary pale yellow stromata, pseudo-immersed, ovoid to pyriform perithecia, filiform asci, filiform ascospores, and flask-shaped conidiogenous cells with solitary conidia.

In the phylogenetic analyses, O. ovatospora was clustered in Hirsutella clade of Ophiocordyceps and formed a sister lineage with O. khokpasiensis , with strong statistical support by BP = 100%, PP = 100%. The total sequence length was 5573 bp for O. ovatospora and O. khokpasiensis , the gap sites of O. ovatospora was 463 bp, and O. khokpasiensis was 3785 bp, their conserved sites were 1788 bp, and variable sites were 26 bp. Ophiocordyceps ovatospora is morphologically similar to O. khokpasiensis by producing pseudo-immersed perithecia, filiform asci and ascospores, monophialidic phialides, and oval conidia. However, the two species differ in size of the perithecia, asci and ascospores. Ophiocordyceps ovatospora has smaller perithecia than O. khokpasiensis (110–140 × 80–110 µm vs. 200–250 × 120–200 µm) but larger asci (110–125 × 5–7 µm vs. 62.5–125 × 4–5 µm) ( Table 2 ).

Figures

FIGURE 2. Ophiocordyceps ovatospora. a. Fungus on termite. b. Fertile part of stroma. c, d. Cross-section of ascoma showing perithecial arrangement. e, f. Asci. g–i. Ascospores. j, k. Colonies on PDA medium. l–o. Conidiogenous cells and conidia. Scale bars: a = 2 cm, b = 0.5 cm, c = 200 µm, d = 100 µm, e–f = 20 µm, g = 10 µm, h–i = 20 µm, j–k = 2 cm, l–o = 10 µm.