Alternaria yamethinensis M. N. Zin & J. X. Deng, 2024

Nwe, Zin Mar, Htut, Khin Nayyi, Aung, Sein Lai Lai, Gou, Ya-Nan, Huang, Cheng-Xin & Deng, Jian-Xin, 2024, Two novel species and a new host record of Alternaria (Pleosporales, Pleosporaceae) from sunflower (Compositae) in Myanmar, MycoKeys 105, pp. 337-354 : 337-354

Alternaria yamethinensis M. N. Zin & J. X. Deng sp. nov.

Fig. 3

Etymology.

The epithet designation is attributed to the Yamethin township, which was the location where the holotype was originally collected.

Holotype.

Myanmar, Mandalay Region, Yamethin Township, Segyi Village (30 ° 21 ' 28.188 " N, 112 ° 08 ' 32.136 " E) on infected leaves of Helianthus annuus , August 2023, Khin Nayyi Htut, ( YZU – H – 2023154 , holotype), ex-type culture ( YZU 231739 ).

Description.

Colonies on PDA are light yellow in the center, white at the edge, with flocculent hyphae, and sulfur yellow to pure yellow in reverse, 38–50 mm in diameter (Fig. 3 a ). On PCA, conidiophores arise from the substrate, are simple, straight or flexuous, septate, light to brown, 19–85 (– 95) × 3–6.5 μm. Conidia arise from the apex or near the apex of the conidiophores, rarely from lateral hyphae, and are narrow ovoid or subellipsoid, blunt-pointed, 17–50 (– 65) × 8–14 µm, with 2–7 transverse septa and 2–6 units per chain with a beak 5–15 µm (Fig. 3 c, e, g ). On V 8 A, conidiophores are 17–65 (– 85.5) × 2–5.5 μm, and conidia are 32–57 (– 63) × 8–15 µm with 2–7 transverse septa, 2–9 units per chain and a beak 1.5–8 µm (Fig. 3 b, d, f ).

Additional isolate examined.

Myanmar, Mandalay Region, Yamethin Township, Segyi Village (30 ° 21 ' 28.188 " N, 112 ° 08 ' 32.136 " E) on infected leaves of Helianthus annuus , August 2023, Khin Nayyi Htut, living culture ( YZU 231738 ) .

Notes.

Phylogenetic analysis based on combined gene regions of ITS, GAPDH, RPB 2, TEF 1, Alt a 1, EndoPG, and OPA 10-2, along with morphological characteristics, clearly separates this species from others. It can be differentiated from A. betae-kenyensis (20–28 × 8–10 µm) by conidial size, A. eichhorniae (50–150 × 4–5 µm) and A. iridiaustralis (15–100 (– 133) × 3.5–4.5 µm) by conidial beak, and A. salicicola (12–38 µm) by conidial body width. Moreover, it is significantly distinct from those four species by conidial units per chain (Table 3 ).

Figures

Figure 3. Morphology of Alternaria yamethinensis sp. nov. from Helianthus annuus: Colony on PDA for 7 days at 25 ° C (a); Sporulation patterns on V 8 A (b) and on PCA (c); Conidiophores on V 8 A (d) and on PCA (e); Conidia on V 8 A (f) and on PCA (g) at 22 ° C. Scale bars: 50 μm (b, c); 25 μm (d – g).