Metarhizium macrosemiae M.J. Chen & B. Huang, 2022

Chen, Ming-Jun, Lin, Yan, Wang, Ting, Zhang, Sheng-Li & Huang, Bo, 2022, Metarhizium macrosemiae sp. nov. and the anamorph of M. guniujiangense on adult cicada from Guniujiang Nature Preserve, southeastern China, Phytotaxa 575 (1), pp. 68-78 : 73-74

Metarhizium macrosemiae M.J. Chen & B. Huang , sp. nov. Fig. 2 .

MycoBank MB 845475

Etymology:— The epithet refers to its original host, an adult of cicada ( Macrosemia ).

Typification:— CHINA. Anhui Province: Guniujiang Nature Preserve, 29º59ˊ– 30º6ˊN, 117º15′– 117º34ˊE, on adult of Macrosemia ( Hemiptera : Cicadidae ) attached to upper side of dicot. leaf in forest, 12 Aug 2020, Y. Lin, T. Wang & M.J. Chen (holotype no. GNJ20200812 -01; ex-type culture no. RCEF 6696, isolated from conidia. Preserved in Research Center for Entomogenous Fungi (RCEF)). GenBank (RCEF6696): ITS = MW718317 , SSU = MW718233 ; LSU = MW718259 ; TEF = MW723113 ; RPB1 = 723144; RPB2 = 723164 .

Known distribution:— Guniujiang Nature Preserve, Anhui, China.

Description:— Specimens found on adult cicada ( Hemiptera : Cicadidae ). The head and internodal membrane of the host insect were covered with white to pale or light green mycelium and powdery cream to green sporulating conidiophores. Synnemata absent. Conidiophores mononematous. Conidia smooth-walled, dimorphic, in chains and adhering laterally to form columns ; microconidia ovoid, ellipsoidal, 4.3–5.2 × 2.4–3.0 μm; macroconidia cylindrical, 12.0–16.0 × 3.4– 4.0 μm ( Fig. 2 A, B ).

Culture characteristics:— Colonies on SDAY/4 reaching 59–62 mm in diam. after 14 d at 25 °C, plane, velutinous to flocculent, farinose when sporulating; light green. Sporulation starts at 7 d after inoculation, reverse pale brown, causing a brown concentric ring outside of the inoculum. Mycelium white, composed of branched, septate, smoothwalled, hyaline hyphae, 2.7–3.3 μm wide. Conidiophores arising from hyphae, smooth-walled. Phialides solitary or in a group of two to three borne directly on metulae, smooth-walled, cylindrical, 5.0–6.5(–8) × 2.4–3.0 μm. Conidia smooth-walled, dimorphic; microconidia formed first, ovoid, ellipsoidal, 3.7–5.0 × 2.1–3.2 μm; macroconidia formed later, cylindrical, (6–)9.5–14.0(–16) × 2.7–3.3 μm.

Colonies on PDA attaining a diam. of 57–60 mm in 14 d, floccose, cream to dark green with age. Sporulation starts at 7 d after inoculation, reverse slightly greenish in outmost. Mycelium white, composed of branched, septate, smoothwalled, hyaline hyphae, 2.4–3.4 μm wide. Conidiophores arising from hyphae, smooth-walled. Phialides solitary or in a group of two to three borne directly on metulae, smooth-walled, cylindrical, 5.0–6.0 × 2.4–3.1 μm. Conidia smoothwalled, dimorphic; microconidia formed first, ovoid, ellipsoidal, 4.1–5.0 × 2.4–2.7 μm; macroconidia formed later, cylindrical, (10–)12.5–18.5 × 2.5–3.5(–4) μm.

Colonies on OA attaining a diam. of 73–76 mm in 14 d, mycelium floccose, cottony, cream to green, powdery while sporulating. Sporulation starts at 7 d after inoculation. Mycelium white, composed of branched, septate, smoothwalled, hyaline hyphae, 2.2–3.0 μm wide. Conidiophores arising from hyphae, smooth-walled. Phialides solitary or in a group of two to three borne directly on metulae, smooth-walled, cylindrical, 5.0–6.0 × 2.4–3.0 μm. Conidia smoothwalled, dimorphic; microconidia formed first, ovoid, ellipsoidal, 3.8–5.0 ×2.2–3.0 μm; macroconidia formed later, cylindrical, (11–)13.0–17.0 × 2.5–3.0 μm.

Additional specimen examined:— CHINA. Anhui Province: Shitai county, Guniujiang Nature Preserve , on adult cicada, Macrosemia sp. , 12 Aug 2020, Y. Lin, T. Wang & M.J. Chen ( GNJ20200812-01 , RCEF 6696 ) .

Notes: — Metarhizium cicadae , M. chaiyaphumense and M. takense are morphologically close to this species. However, M. macrosemiae and M. cicadae parasitize adult cicadas while M. chaiyaphumense and M. takense infect cicada nymphs. In M. macrosemiae the phialides and conidia on OA and PDA are smaller than in M. cicadae . Furthermore, M. macrosemiae is distinguished from M. chaiyaphumense by its host, growth rate on SDAY/4 and PDA, and size of the phialides, while it differs significantly from M. takense in colony colour, growth rate on SDAY/4 and PDA, and the presence of macroconidia ( Table 2 ).

Figures

FIGURE 2. Metarhizium macrosemiae (GNJ20200812-01, culture ex-type RCEF 6696). A. Fungus on adult cicada. B. Macroconidia on insect host. C. Microconidia on insect host. D–E. Colonies on SDAY/4. F. Conidiophores bearing phialides and conidia on SDAY/4. G. Macro- and microconidia on SDAY/4. H–I. Colonies on PDA. J. Conidiophores bearing phialides and conidia on PDA. K. Macro- and microconidia on PDA. L–M. Colonies on OA. N. Conidiophores bearing phialides and conidia on OA. O. Macro- and microconidia on OA. Scale bars: A = 10 mm, D–E, H–I, L–M = 15 mm, B–C, F–G, J–K, N–O = 10 μm.