Fusarium semanoti Lin Huang, Jiao He, D. W. Li 2026, sp. nov.

Fusarium semanoti Lin Huang, Jiao He, D. W. Li, sp. nov.

Fig. 8

Etymology.

semanoti, L. insect gen. n. of Semanotus, referring to the association with the cedar longhorned beetle, Semanotus bifasciatus.

Holotype.

China • Shandong Province, Jinan City, Beijiao State-owned Forest Farm, 36 ° 46 ' 03 " N, 116 ° 51 ' 46 " E, isolated from branch of Taxodium hybrid ‘ Zhongshanshan’, August 2024, Lin Huang, (holotype: CFCC 72663). Holotype specimen is a living specimen being maintained via lyophilisation at the China Forestry Culture Collection Center (CFCC). Ex-type (SG 3-38) is maintained at the Forest Pathology Laboratory, Nanjing Forestry University.

Host / distribution.

From the T. hybrid ‘ Zhongshanshan’ at the Beijiao State-owned Forest Farm, Jinan City, Shandong Province, China.

Description.

Sexual state not observed. Asexual state: sporulation abundant from sporodochia, rarely from conidiophores formed directly on the substrate mycelium. Conidiophores in the aerial mycelium absent. Sporodochia bright orange-coloured, formed abundantly on carnation leaves. Conidiophores in sporodochia (13.9 –) 18.1–25.4 (– 34.3) μm, (mean ± SD = 21.7 ± 3.6 μm, n = 36), irregularly branched and densely packed, bearing apical whorls of 1–2 phialides; sporodochial phialides subulate to subcylindrical, (6.5 –) 9.7–16.8 (– 24.6) × (3 –) 3.2–4.2 (– 4.8) μm, (mean ± SD = 13.3 ± 3.5 × 3.7 ± 0.5 μm, n = 31), smooth, thin-walled. Sporodochial macroconidia colourless, straight or slightly curved, wider at the middle or apical part, tapering towards the base, with a blunt and often curved apical cell and a foot-like to slightly notched basal cell, 3–5 - septate, smooth, thin-walled, (29.9 –) 34.3–44.5 (– 48.5) × (4.3 –) 4.7–5.6 (– 6) μm, (mean ± SD = 39.4 ± 5.1 × 5.2 ± 0.4 μm, n = 35). Chlamydospores developed in large numbers in hyphae, 0 - septate, globose to ellipsoidal, constricted at the septum, intercalary or terminal or solitary with mostly a pale colour and smooth, (6.7 –) 7.4–9.6 (– 11.2) × (6.1 –) 6.6–8.3 (– 9.7) μm, (mean ± SD = 8.5 ± 1.1 × 7.5 ± 0.8 μm, n = 34). Microconidia not observed.

Culture characteristics.

On PDA incubated at 25 ° C in the dark, colonies exhibited an average radial growth rate of 11.3 mm / d. The colony surface appeared white, with a felty to cottony texture. Abundant aerial mycelium was observed, ranging from loosely to densely floccose, with regular margins and fimbriate edges. The reverse side displayed a bright yellow pigmentation. No distinctive odour. On OMA under the same conditions, colonies developed regularly, completely covering the entire 70 - mm OMA plate within five days. The reverse side white with minimal grey pigmentation. On SNA incubated at 25 ° C in the dark, colonies grew uniformly at 10.66 mm / d. The colony surface was pure white, with sparse aerial mycelia that formed regular peripheral rings. The reverse side remained pure white, with no observable diffusible pigments.

Additional materials examined.

Notes.

The isolates of F. semanoti were phylogenetically closely related to F. odoratissimum InaCC F 822 (ex-holotype) (Fig. 5). Between F. semanoti isolates and ex-holotype of F. odoratissimum InaCC F 822, there were 21 / 1432 differences in RPB 1, 1 / 838 in RPB 2 and 1 / 573 in TEF- 1 α. The PHI analysis showed that there was no significant recombination between F. semanoti isolates and its related species (Φ _w = 1.0) (Fig. 6 A). Morphological analysis revealed that macroconidia produced by isolate SG 2-38 of F. semanoti (34.3–44.5 × 4.7–5.6 μm) were much smaller than those of the ex-holotype (InaCC F 822) of F. odoratissimum (44–79 × 6–8 μm), as characterised by Maryani et al. (2019). Another difference is that SG 2-38 of F. semanoti does not develop microconidia, while the ex-holotype (InaCC F 822) of F. odoratissimum does. Thus, F. semanoti is recognised as a new species in F. oxysporum species complex.