Diaporthe alnicola Ning Jiang, 2025

Diaporthe alnicola Ning Jiang sp. nov.

Fig. 5 View Figure 5

Etymology.

“ Alni ” refers to the host genus Alnus , and “ - cola ” means inhabiting.

Description.

Associated with leaf spot disease of Alnus nepalensis . Teleomorph: Undetermined. Anamorph: Conidiomata formed on PDA pycnidial, scattered, erumpent, pulvinate to subglobose, dark brown, 150–350 μm diam. Conidiophores indistinct, usually reduced to conidiogenous cells. Conidiogenous cells cylindrical, attenuate towards the apex, hyaline, phialidic, 9.5–33 × 2–3 μm. Alpha conidia aseptate, hyaline, smooth, guttulate, cylindrical, straight, base truncate, (6 –) 6.5–7 (– 7.5) × (2 –) 2.5–3 (– 3.5) μm (x ̄ = 6.8 × 2.6 μm, n = 50), L / W = 2–3.4. Beta conidia aseptate, hyaline, smooth, guttulate, filiform, tapering towards both ends, curved, (13 –) 14.5–22 (– 24) × 1.5–2.5 μm (x ̄ = 18.3 × 2.1 μm, n = 50), L / W = 5.9–12.5. Gamma conidia not observed.

Culture characteristics.

Colonies on PDA at 25 ° C are spreading, flocculent, forming abundant aerial mycelium and an undulate margin, initially white, turning mouse gray and reaching a diameter of 90 mm after 10 d, developing dark brown conidiomata with orange conidial masses after 20 d. Colonies on MEA at 25 ° C are flat, spreading, feathery, with a smooth entire margin, white, reaching a diameter of 90 mm after 15 d, sterile. Colonies on SNA at 25 ° C are flat, spreading with a smooth entire margin, white, reaching 90 mm in diameter after 20 d, developing dark brown conidiomata with orange conidial masses after 30 d.

Materials examined.

China • Xizang Autonomous Region (Tibet), Linzhi City, Bayi District, Pailong Town , 30°4'22"N, 95°8'2"E, 2192 m, from leaf spots of Alnus nepalensis , 9 Jul. 2024, Ning Jiang, Jieting Li & Haoyin Zhang (holotype CAF 800100 About CAF , ex-paratype cultures CFCC 70997 and CFCC 70998 ) GoogleMaps .

Notes.

Diaporthe alnicola , identified from leaf spots on Alnus nepalensis in this study, is phylogenetically closely related to D. virgiliae , which originates from the rot root of Virgilia oroboides in South Africa (Fig. 3 View Figure 3 ). Morphologically, D. alnicola is similar to D. virgiliae in terms of the size of alpha and beta conidia (alpha conidia: 6.5–7 × 2.5–3 μm in D. alnicola vs. 5.2–8 × 1.1–3.5 μm in D. virgiliae ; beta conidia: 14.5–22 × 1.5–2.5 μm in D. alnicola vs. 17.1–25.4 × 1–1.8 μm in D. virgiliae ). However, they can be distinguished by the size of their conidiogenous cells (9.5–33 × 2–3 μm in D. alnicola vs. 12.3–21.3 × 0.7–1.5 μm in D. virgiliae ) ( Machingambi et al. 2015). Furthermore, D. alnicola differs from D. virgiliae at the nucleotide level (ITS, 11 / 432; tub 2, 7 / 743).