Fusarium citri-sinensis L. Zhao & J. X. Deng, 2022

Zhao, Lin, Wei, Xin, Huang, Cheng-Xin, Yi, Ji-Ping, Deng, Jian-Xin & Cui, Meng-Jiao, 2022, Fusarium citri-sinensis sp. nov. (Ascomycota: Nectriaceae) isolated from fruit of Citrus sinensis in China, Phytotaxa 555 (3), pp. 259-266 : 263-264

Fusarium citri-sinensis L. Zhao & J. X. Deng , sp. nov. Fig. 2 A–H

MycoBank: MB843205

Etymology: In reference to the host, Citrus sinensis .

Type: China, Hubei Province, from fruit of Citrus sinensis . July , 2019, J. X. Deng (culture ex-type YZU 191316 ) .

Description: Colonies on PDA grown in the dark reaching 4.4–4.5 cm diam after 7 d at 25 °C, flat, with sparse and loose aerial mycelium, colony margin smooth, pale pink (2A); reverse pinkish-white (2B). Pigment pale pink on PDA. Conidiophores in sporodochia variable in length, verticillately branched and densely packed; Sporodochial macroconidia thin, falcate to almost straight, with parallel walls, apical cell with a distinct beak, basal cell foot-shaped, 3–6-septate, 3-septate macroconidia 27–42 × 4.5–5.5 μm (av.: 36.1 × 4.9 μm, n=50); 4-septate macroconidia 41.5–51(– 62) × 4–5.5 μm (av.: 46.7 × 4.8 μm, n=50); 5-septate macroconidia 46.5–60(–66) × 4.5–5.5 μm (av.: 53.2 × 5.1 μm, n=50); 6-septate macroconidia (53.5–)58–68 × 4.5–6(–6.5) μm (av.: 62.8 × 5.4 μm, n=50). Sporodochial microconidia oval, almost oval with a truncate base, kidney shaped, pear-shaped and straight to slightly curved, 0–2-septate, 0-septate macroconidia 9.5–17.5(–24) × 3.5–5 μm (av.: 13.9 × 4 μm, n=30); 1-septate macroconidia 15.5–25(–32.5) × 3–5 μm (av.: 19.3 × 3.9 μm, n=50); 2-septate macroconidia 17–27(–32.5) × 3–5 μm (av.: 21 × 4 μm, n=50). Chlamydospores formed spherical to oval shape, 7.5–10(–15) × 6.5–10(–12.5) μm (av.: 8.7 × 7.9 μm, n=50).

Materials examined: China, Hubei Province, from rot fruit of Citrus sinensis , November 2018, J . X. Deng; living cultures YZU 181391 and YZU 181393 .

Note: The highest similarity with Fusarium cassiae (MFLUCC 18-0573) was found during the BLAST search of RPB2 gene sequence, a taxonomic important gene locus for Fusarium . Phylogenetic analysis of the species based on a combined dataset of ITS, EF-1α, and RPB2 gene fragments fell in an individual clade close to F. cassiae , F. stilboides and F. lateritium Clade II A in Fusarium lateritium species complex. Its colony characteristics on PDA are similar to F. cassiae , but F. cassiae only produce sexual conidia. Fusarium citri-sinensis produces macroconidia with septa up to 6 while those conidia of F. stilboides can be up to 16. Besides, chlamydospores formation was only found during the morphological observations of strain YZU 191316.

Figures

FIGURE 2. Morphological characteristics of Fusarium citri-sinensis (YZU 191316). A–B. colonies on PDA; C–D. conidium formed on the carnation leaf; E. microconidia; F–G. chlamydospores; H. macroconidia.—Scale bars: C–G = 10 μm, H = 25 μm.