Diaporthe beijingensis Y.Y. Zhou, W. Zhang & J.Y. Yan. sp. nov.

Index Fungorum number: IF 902257; Mycobank number: MB 902257; Facesoffungi number: FoF 15928; Fig. 1

Etymology – ‘beijingensis’ refers to Beijing in China from which it was isolated.

Associated with leaf spots of Prunus avium living leaves. Sexual morph: Produced on 30 days old PDA culture. Perithecia 220–397 μm diam., subglobose, black, solitary to scattered, ostiolate. Perithecial necks 38–103 μm., black, subcylindrical, tapering towards the apex. Asci 25.6–37.2×5–8 μm (x̅=31.8×6.7 μm, n=30), unitunicate, 8-spored, sessile, ellipsoid to clavate, widest at centre and rounded towards the apices. Ascospores 5.6–8.5×2–3 μm (x̅=6.5×2.6 μm, n=50), hyaline, often biguttulate, ellipsoid to fusoid, Asexual morph: Conidiomata 180–350 μm diam., pycnidial, globose or irregular, scattered, orange cream conidial drops exuded from the ostioles. Alpha conidia 5–7.5×1.5–3 μm (x̅=6.9×2.7 μm, n=60), hyaline, biguttulate, fusoid to ellipsoid, Beta and Gamma conidia not observed.

Culture characteristics – Colonies on PDA entirely white both on the surface and reverse. Reverse becomes amber with time. Aerial mycelium felty, colonies reaching 75 mm diam., after 4 days in room temperature.

Material examined – China, Beijing, on leaf spot of Prunus avium L. (Rosaceae), 27 September 2022, Yueyan Zhou and Wei Zhang 22-HD-2-5a (JZBH320260, holotype), extype JZB320260.

GenBank numbers – JZB320260: ITS: PP859267; tef1-α: PP869043; tub2: PP869034; cal: PP869037; his: PP869040. JZB320261: ITS: PP859268; tef1-α: PP869044; tub2: PP869035; cal: PP869038; his: PP869041. JZB320262: ITS: PP859269; tef1-α: PP869045; tub2: PP869036; cal:
PP869039; his: PP869042.

Notes – Diaporthe beijingensis forms a distinct clade within Diaporthe and is sister to D. caulivora. It forms an independent branch with 100% ML support. The morphological characters of our new collection are similar to D. caulivora (CBS 127268, ex-neotype). However, the base pair showed 2.1% (11/536) differences in ITS, 4.4% (15/343) in tef1-α, 1.6% (7/429 bp) in act, 2.2% (8/356) in cal, and 3.2% (15/475) in his between D. beijingensis (JZB320260) and D. caulivora (CBS 127268). Therefore, we introduce Diaporthe beijingensis as a new species.

Figure 1 – Diaporthe beijingensis (JZB320260, holotype). a Surface, b Reverse view of 4-days old colony on PDA. c Ascomata. d Asci. e Ascospores. f Conidiomata. g Conidia. Scale bars: c=20 μm; d, e=10 μm; f=100 μm; g=10 μm