Four novel Pleurocordyceps (Polycephalomycetaceae) species from China

Abstract

Entomopathogenic fungi comprise an ecologically important group of specialized pathogens infecting other fungi, invertebrates, and plants. These fungi are species-rich with high diversity and broad distribution worldwide. The majority of entomopathogenic fungi belong to clavicipitoids, which consist of the hypocrealean families, Clavicipitaceae, Cordycipitaceae, Ophiocordycipitaceae, and Polycephalomycetaceae. The latter is a newly established entomopathogenic family that recently separated from the family Ophiocordycipitaceae to accommodate the genera, Perennicordyceps, Pleurocordyceps, and Polycephalomyces. In recent years, Polycephalomycetaceae has been enriched with parasitic and hyperparasitic fungi. With 16 species spread across China, Ecuador, Japan, and Thailand, Pleurocordyceps is the most speciose genus in the family. In this study, we expand the number of taxa in the genus by introducing four new Pleurocordyceps species from China, namely, P. clavisynnema, P. multisynnema, P. neoagarica, and P. sanduensis. We provide detailed descriptions and illustrations and infer genus-level phylogenies based on a combined 6-loci gene sequence dataset comprising the internal transcribed spacer gene region (ITS), small subunit ribosomal RNA gene region (SSU), large subunit rRNA gene region (LSU), translation elongation factor 1-alpha gene region (TEF-1α), RNA polymerase II largest subunit gene region (RPB1), and RNA polymerase II second largest subunit (RPB2). This study contributes to knowledge with regard to the diversity of Pleurocordyceps specifically and entomopathogenic Hypocreales more broadly.

Keywords: Polycephalomycetaceae; entomopathogenic fungi; morphology; phylogeny; taxonomy.

Figure 1

Maximum likelihood phylogenetic tree of 58 taxa and 4,791 sites combining LSU, SSU, ITS, tef-1α, rpb1, and rpb2 sequence data. MLBS higher than 75% and PP >0.90 are denoted near the nodes as MLBS/PP, and the newly generated sequences are in red bold font. The genus clade Pleurocordyceps is highlighted in green, while the outgroup is marked with a light orange background.

Figure 2

Pleurocordyceps clavisynnema (GZLG 23-102, Holotype). (a, b) Host: Ophiocordyceps neogryllotalpae (c) Upper side of the colony. (d) Synnemata on the culture. (e) Conidiophores. (f, g) α-phialides. (h) β-phialides. (i) α-conidia. (J) β-conidia. Scale bars: (b, c) 3 cm, (d) 0.5 cm, (e) 100 μm, (f–h) 20 μm, (i, j) 3 μm.

Figure 3

Pleurocordyceps multisynnema (GZLG 23-101, holotype) (a) Habitat. (b) Overview of Pleurocordyceps multisynnema. (c) Synnemata on the host. (d) Host of Paraisaria sp. (e, f) Section of host. (g) β-phialides. (h) α-phialides. (i) α-conidia and β-conidia. (j) Culture from above on PDA medium. (k–m) Synnemata on the culture. (n) α-phialides. (o) β-phialides. (p) α-conidia. (q) β-conidia. Scale bars: (b, d, j) 1 cm, (c) 0.2 cm, (e) 300 μm, (f) 200 μm, (g, h) 10 μm, (i, p, q) 3 μm, (k, l) 0.5 cm, (m) 500 μm, (n, o) 20 μm.

Figure 4

Pleurocordyceps neoagarica (GZLG 23-103, Holotype). (a, b) Host: Ophiocordyceps neogryllotalpae (c) Upper side of the colony. (d, e) Synnemata on the culture. (f) Conidiophores. (g, h) Phialides. (i) Conidia. Scale bars: (b, c) 5 cm, (d) 3 mm, (e) 200 μm, (f) 20 μm, (g, h) 10 μm, (i) 2 μm.

Figure 5

Pleurocordyceps sanduensis (GZLG 23-104, Holotype). (a) Host: Ophiocordyceps neogryllotalpae (b, c) Upper and back side of the colony. (d, e) Conidial masses on the culture. (f) Conidiophores. (g) α-phialides. (h) β-phialides (I) α-conidia and β-conidia. Scale bars: (a) 5 cm; (b–d) 1 cm, (e) 0.5 cm, (f) 50 μm, (g) = 10 μm, (h) 20 μm, (i) 5 μm.