Diaporthe linzhiensis Ning Jiang 2025, sp. nov.

Diaporthe linzhiensis Ning Jiang sp. nov. Fig. 7 Etymology. Named after the collection site of the type specimen, Linzhi City. Description. Associated with branch canker disease of Alnus nepalensis. Teleomorph: Undetermined. Anamorph: Conidiomata pycnidial, immersed in bark, scattered, erumpent through the bark surface, conical, with a solitary locule, 300–500 μm diam., 250–400 μm high. Conidiophores reduced to conidiogenous cells. Conidiogenous cells cylindrical, attenuate towards the apex, hyaline, phialidic, straight or slightly curved, 5.5–16 × 1.5–3 μm. Alpha conidia not observed. Beta conidia aseptate, hyaline, smooth, guttulate, filiform, tapering towards both ends, straight or slightly curved, (23.5 –) 24.5–29 (– 30) × 1.5–2 μm (x ̄ = 26.6 × 1.8 μm, n = 50), L / W = 12.4–19.4. Gamma conidia not observed. Culture characteristics. Colonies on PDA at 25 ° C are spreading, flocculent, forming abundant aerial mycelium and concentric zones with an undulate margin, initially white, turning pale luteous, and reaching a diameter of 90 mm after 10 d, sterile. Colonies on MEA at 25 ° C are flat, spreading, with a smooth entire margin, white, reaching a diameter of 60 mm after 20 d, sterile. Colonies on SNA at 25 ° C are flat, spreading, forming concentric zones with undulate margins, white, reaching 80 mm in diameter after 20 d, sterile. Materials examined. China • Xizang Autonomous Region (Tibet), Linzhi City, Bomi County, Tongmai Town, 30°5'53"N, 95°3'49"E, 2055 m, from branches of Alnus nepalensis, 9 Jul. 2024, Ning Jiang, Jieting Li & Haoyin Zhang (holotype CAF 800101, ex-paratype cultures CFCC 71057 and N 266 C). Notes. Diaporthe linzhiensis is phylogenetically closely related to D. alnicola, D. heterophyllae, and D. virgiliae (Fig. 2). Both D. linzhiensis and D. alnicola infect Alnus nepalensis in China, while D. heterophyllae is found on Acacia heterophylla in France, and D. virgiliae inhabits Virgilia oroboides in South Africa (Machingambi et al. 2015; Marín-Felix et al. 2019). Morphologically, D. linzhiensis shares a similar conidiogenous cell size with D. alnicola and D. heterophyllae, which is wider than that of D. virgiliae (5.5–16 × 1.5–3 μm in D. linzhiensis vs. 9.5–33 × 2–3 μm in D. alnicola vs. 6–9 × 1–2 μm in D. heterophyllae vs. 12.3–21.3 × 0.7–1.5 μm in D. virgiliae). Additionally, D. linzhiensis has longer beta conidia compared to the other species (24.5–29 × 1.5–2 μm in D. linzhiensis vs. 14.5–22 × 1.5–2.5 μm in D. alnicola vs. 17–24 × 1–2 μm in D. heterophyllae vs. 17.1–25.4 × 1–1.8 μm in D. virgiliae) (Machingambi et al. 2015; Marín-Felix et al. 2019). At the nucleotide level, D. linzhiensis also differs from D. alnicola (ITS, 23 / 547; cal, 2 / 382; his 3, 6 / 469; tef 1, 4 / 349; tub 2, 6 / 778), D. heterophyllae (ITS, 28 / 560; cal, 11 / 420; his 3, 6 / 447; tef 1, 12 / 326; tub 2, 3 / 406), and D. virgiliae (ITS, 16 / 434; tub 2, 7 / 743).