Fusarium xylosmatis Q. Y. Liu, X. G. Zhang & J. W. Xia, 2025

Fusarium xylosmatis Q. Y. Liu, X. G. Zhang & J. W. Xia sp. nov.

Fig. 5 View Figure 5

Etymology.

Referring to the genus name of the host plant Xylosma congesta .

Typus.

China • Yunan Province, Nanuo Mountain , on leaves of Xylosma congesta , 3 March 2023, Q. Y. Liu ( HMAS 353394 View Materials , holotype), ex-holotype culture CGMCC 3.27794 View Materials = SAUCC 2416-1 .

Description.

Conidiophores arising from aerial mycelium, 25–35 μm long, unbranched or irregularly branched, often reduced to single phialides, subulate to subcylindrical, smooth, 12–15 × 4–5 μm, periclinal thickening inconspicuous; aerial conidia ellipsoidal to falcate, slightly curved, tapering towards both ends, with a blunt to conical and slightly curved apical cell and papillate basal cell, (0 –) 3–5 - septate; 0 - septate conidia: 16–20 × 3–4 μm (av. 21 × 4 μm, n = 5); 1 - septate conidia: (12 –) 15–19 (– 29) × 3–4 μm (av. 18 × 4 μm, n = 33); 2 - septate conidia: (16 –) 16–23 (– 29) × 3–5 μm (av. 21 × 4 μm, n = 18); 3 - septate conidia: (20 –) 30–36 (– 41) × 4–5 μm (av. 31 × 5 μm, n = 45); 4 - septate conidia: (31 –) 30–36 (– 34) × 4–6 μm (av. 34 × 5 μm, n = 26); 5 - septate conidia: (30 –) 37–41 (– 43) × 4–6 μm (av. 38 × 5 μm, n = 26). Sporodochia pale orange, formed abundantly on surface of carnation leaves. Sporodochial conidiophores densely and irregularly branched, 15–19 × 2–3 μm, bearing apical whorls of 1–2 phialides; sporodochial phialides monophialidic, subulate to subcylindrical, 10–12 × 2–3 μm, smooth, and thin-walled; sporodochial conidia falcate, curved dorsiventrally, straight to slightly curved, tapering towards both ends, with slightly papillate, curved apical cell and a notched to foot-like basal cell, (0 –) 3–4 (– 5) - septate, hyaline, smooth, and thin-walled; 0 - septate conidia: 28–30 × 3–4 μm (av. 29 × 4 μm, n = 5); 1 - septate conidia: (16 –) 21–32 (– 36) × 3–5 μm (av. 27 × 4 μm, n = 11); 2 - septate conidia: 22–23 × 3–4 μm (av. 23 × 4 μm, n = 4); 3 - septate conidia: (22 –) 25–33 (– 41) × 3–6 μm (av. 32 × 4 μm, n = 38); 4 - septate conidia: (33 –) 35–38 (– 43) × 4–6 μm (av. 37 × 5 μm, n = 26); 5 - septate conidia: (36 –) 38–40 (– 44) × 4–6 μm (av. 40 × 5 μm, n = 16). Chlamydospores abundant, globose, subglobose to ellipsoid, terminal or intercalary, solitary, in pairs, or forming long chains, 8–12 μm diameter.

Culture characteristics.

Colonies on PDA incubated at 25 ° C in the dark, reaching 71–79 mm diameter in 7 d; aerial mycelia dense, flat, white, colony margin entire; reverse yellowish white, radiate, aerial mycelia dense, odor absent. Colonies on OA grown in the dark, reaching 69–77 mm diameter after 7 d at 25 ° C, flat, aerial mycelia scant, colony margin entire, white; reverse white, odor absent.

Additional material studied.

China • Yunan Province, Nanuo Mountain , on leaves of Xylosma congesta , 3 March 2023, Q. Y. Liu ( HSAUP 21624 ), living culture CGMCC 3.27795 View Materials = SAUCC 2416-2 .

Notes.

Phylogenetically, F. xylosmatis ( CGMCC 3.27794) is closely related to the species F. weifangense ( LC 18333); there were 7 / 535 differences in cal, 9 / 657 in rpb 2, and 8 / 462 in tef 1. Morphologically, F. xylosmatis ( CGMCC 3.27794) is distinguished from F. weifangense ( LC 18333) by the number of sporodochial conidial septa (0–5 - septate in F. xylosmatis ( CGMCC 3.27794) vs. 3–7 - septate in F. weifangense ( LC 18333 )) ( Han et al. 2023; Zhang et al. 2023 a).