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

Fig. 2

Etymology.

The specific epithet refers to the location, Myanmar.

Holotype.

Myanmar, Mandalay Region, Yamethin Township, Segyi Village (30 ° 21 ' 28.188 " N, 112 ° 08 ' 32.136 " E), collected from infected leaves of Helianthus annuus in August 2023 by Khin Nayyi Htut ( YZU – H – 2023154 , holotype). Ex-type culture ( YZU 231736 ) was also obtained.

Description.

Colonies on PDA are circular, light vinaceous buff with a white halo at the edge, velvety, cottony, honey to white in reverse, 68–70 mm in diameter (Fig. 2 a ). On PCA, conidiophores arise directly from lateral or apical aerial hyphae or medium, lightly flexuous, sometimes geniculate at the apex, 27.5–85 (– 90) × 2–4.5 μm, conidia emerge from the apex or geniculate loci, short to long ellipsoid or narrow-ovoid, 10–30 (– 42) × 7–11 μm, 2–5 transverse septa, 2–6 units per chain, beak 3–12 μm (Fig. 2 c, e, g ). On V 8 A, conidiophores arise from near the apex of the terminal hyphae, 24–65 (– 70) × 3–5 μm, conidia 8–29 (– 33) × 3–14 μm, 2–5 transverse septa, 3–6 units per chain, beak 1–9 μm (Fig. 2 b, d, f ).

Additional isolate examined.

Myanmar, Mandalay Region, Yamethin Township, Segyi Village (30 ° 21 ' 28.188 " N, 112 ° 08 ' 32.136 " E) from the infected leaves of Helianthus annuus , August 2023, Khin Nayyi Htut, living cultures ( YZU 231735 ) .

Notes.

This species is phylogenetically grouped with A. koreana , A. orobanches , and A. ovoidea , based on sequences from ITS, GAPDH, RPB 2, TEF 1, Alt a 1, EndoPG, and OPA 10-2 genes. It is distinct from A. koreana and A. ovoidea in its smaller conidial body size, particularly in width, and its sporulation patterns which produce catenulate conidia up to 6 units on PCA and V 8 A media, rather than those of the two closely related species (up to 2 units) on SNA and PDA (Table 3 ).

Figures

Figure 2. Morphology of Alternaria myanmarensis 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).