Fusarium cumulatum Dewing, Visagie & Yilmaz 2025, sp. nov.
Creators: name: Dewing, Claudette
name: Visagie, Cobus M.
name: Steenkamp, Emma T.
name: Wingfield, Brenda D.
name: Yilmaz, Neriman
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Fungi
Ascomycota
Dothideomycetes
Hypocreales
Nectriaceae
Fusarium
Fusarium cumulatum

description: Fusarium cumulatum Dewing, Visagie & Yilmaz sp. nov.
Fig. 2
Etymology.
Latin, cumulatum, meaning to accumulate or heap up, named for its abundant chlamydospore formation.
Type.
South Africa • Eastern Cape, from mixed pasture samples, May 2020, collected by A. Davis (holotype: PRU (M) 4601, dried specimen in a metabolically inactive state); (ex-type strain: CBS 151773 = CMW 58688 = CN 104 D 3).
Description.
Conidiophores borne on aerial mycelium scarce, 13–71 μm tall, unbranched, bearing terminal phialides, often reduced to single phialides; aerial phialides scarce, monophialidic, subulate to subcylindrical, proliferating percurrently, smooth- and thin-walled, 2.5–20 × 2–4 μm, with inconspicuous thickening; aerial conidia absent. Sporodochia orange, present on the surface of carnation leaves and on agar. Sporodochial conidiophores densely and irregularly branched, bearing apical whorls of 2–5 phialides; sporodochial phialides monophialidic, subulate to subcylindrical, 7–16.5 × 2–4 μm, smooth, thin-walled, with inconspicuous periclinal thickening; sporodochial conidia falcate, sometimes becoming sinuate, slender, curved dorsiventrally, tapering towards both ends, with an elongated or whip-like curved apical cell and a barely notched to prominently extended basal cell, 1–5 - septate, hyaline, smooth- and thin-walled; 1 - septate conidia 16 × 4 μm (n = 1); 2 - septate conidia 18–30 × 3–4 μm (av. 25.2 × 3.6 μm) (n = 3), 3 - septate conidia 23–42 × 2.5–4 μm (av. 25.2 × 3.5 μm) (n = 15), 4 - septate conidia 25.5–54.5 × 2.5–4 μm (av. 43.0 × 3.4 μm) (n = 14), 5 - septate conidia 38–57 × 3–4.5 μm (av. 49.1 × 3.8 μm) (n = 17). Chlamydospores abundant, globose to subglobose, subhyaline, smooth- to slightly rough-walled, terminal or intercalary, solitary or in pairs forming chains, 8–19 μm diam.
Culture characteristics.
Colonies on PDA incubated at 25 ° C in the dark with an average radial growth rate of 2–8 mm / d, reaching 44–46 mm diam at 25 ° C; surface white, flat, felty to velvety, radiate, with abundant aerial mycelium, margin irregular. Additional colony diam (after 7 d, in mm): PDA 10 ° C 13–15; PDA at 15 ° C 22–26; PDA at 20 ° C 27–32; PDA at 30 ° C 64–75; PDA at 35 ° C 0–2. Odour absent. Reverse yellowish white (2 A 2). Diffusible pigments absent. On OA in the dark, occupying an entire 90 mm Petri dish in 7 d; surface white to pale yellow, flat, felty to velvety, radiate, with abundant aerial mycelium, margin irregular, filiform. Reverse yellowish white (4 A 2). Diffusible pigments absent. On SNA with sparse aerial mycelium, sporulation moderate on the surface of the medium.
Additional materials examined.
South Africa • Eastern Cape, from mixed pasture samples, May 2020, collected by A. Davis, isolated by C. Dewing, Humansdorp area: CMW 58686 = CN 071 B 9, CMW 58687 = CN 071 E 5, close to Villa Fonte: CMW-IA 002138 = CMW 60936 = CN 071 G 4.
Notes.
Fusarium cumulatum belongs to the Equiseti - clade and is closely related to F. arcuatisporum (FIESC 7) (Wang et al. 2019), F. brevicaudatum (FIESC 6) (Xia et al. 2019), F. heslopiae (Tan and Shivas 2024), F. longicaudatum (Xia et al. 2019), F. khuzestanicum and F. oryzicola (Afzalinia et al. 2024). No aerial phialides or conidia were observed for the closely related species (Wang et al. 2019; Xia et al. 2019; Afzalinia et al. 2024) compared to the few scarce monophialides we recorded for F. cumulatum. Sporodochia and chlamydospores were present in F. cumulatum and its closely related species, whereas F. oryzicola lacked chlamydospore formation (Wang et al. 2019; Xia et al. 2019; Afzalinia et al. 2024). Sporodochial conidia of F. cumulatum (1–5 - septate; 16–57 × 2.5–4 μm) are similar in length to F. arcuatisporum (5 - septate; 29–49.5 × 4–6 μm) (Wang et al. 2019) and F. brevicaudatum (1–5 - septate; 8–64 × 3–5 μm) (Xia et al. 2019), while generally being shorter than those observed in F. khuzestanicum (4–7 (– 9) - septate; 48.5–82 × 2.7–4.3 μm) (Afzalinia et al. 2024), F. longicaudatum ((3 –) 5–6 (– 7) - septate; 45–81 × 4–5 μm) (Xia et al. 2019) and F. oryzicola (4–7 - septate; 33.5–77.9 × 3–4 μm) (Afzalinia et al. 2024). Colony colour on PDA differs between F. cumulatum and closely related species (Wang et al. 2019; Xia et al. 2019; Afzalinia et al. 2024) as other species show more colour across the surface and reverse compared to the white surface and yellowish white (2 A 2) reverse of F. cumulatum, whereas the colony colour of F. khuzestanicum and F. oryzicola is white to pale grey. The growth rate after 7 d on PDA for F. cumulatum (44–46 mm) is slower than that of F. arcuatisporum (48–53 mm) (Wang et al. 2019), F. brevicaudatum (50–58 mm) (Xia et al. 2019) and F. longicaudatum (full 90 mm plate) (Xia et al. 2019). The growth rate for F. khuzestanicum (74–76 mm) (Afzalinia et al. 2024) and F. oryzicola (74 mm) (Afzalinia et al. 2024) was measured after 5 d on PDA but appears to be faster than that of F. cumulatum. No morphological data is currently available for F. heslopiae to compare with. Pairwise comparisons revealed that F. cumulatum differs from other species by at least 3, 6 and 16 bp for CaM, RPB 2 and TEF, respectively.
description: Published as part of Dewing, Claudette, Visagie, Cobus M., Steenkamp, Emma T., Wingfield, Brenda D. & Yilmaz, Neriman, 2025, Three new species of Fusarium (Nectriaceae, Hypocreales) isolated from Eastern Cape dairy pastures in South Africa, pp. 241-271 in MycoKeys 115 on pages 241-271, DOI: 10.3897/mycokeys.115.148914