Two novel species and a new host record of Alternaria (Pleosporales, Pleosporaceae) from sunflower (Compositae) in Myanmar Author Nwe, Zin Mar https://orcid.org/0009-0000-6376-8306 Department of Plant Protection, College of Agriculture, Yangtze University, Jingzhou 434025, China Author Htut, Khin Nayyi https://orcid.org/0009-0009-9498-8040 MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-Construction by Ministry and Province), Yangtze University, Jingzhou 434025, China Author Aung, Sein Lai Lai https://orcid.org/0009-0006-2738-5598 Department of Plant Protection, College of Agriculture, Yangtze University, Jingzhou 434025, China Author Gou, Ya-Nan https://orcid.org/0009-0000-6376-8306 Department of Plant Protection, College of Agriculture, Yangtze University, Jingzhou 434025, China Author Huang, Cheng-Xin 0000-0001-7770-5242 Department of Plant Protection, College of Agriculture, Yangtze University, Jingzhou 434025, China Author Deng, Jian-Xin 0000-0001-7304-5603 Department of Plant Protection, College of Agriculture, Yangtze University, Jingzhou 434025, China text MycoKeys 2024 2024-06-07 105 337 354 journal article 298200 10.3897/mycokeys.105.123790 d715a50d-9acf-486f-b0fa-eb2bd1c3ae1b 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 ). 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 ). 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 ).