Diaporthe amygdali (Delacr.) Udayanga, Crous & K. D. Hyde

Li, Jieting, Li, Yi, Li, Jiangrong & Jiang, Ning, 2025, Species of Diaporthe (Diaporthaceae, Diaporthales) associated with Alnus nepalensis leaf spot and branch canker diseases in Xizang, China, MycoKeys 116, pp. 185-204 : 185-204

Diaporthe amygdali (Delacr.) Udayanga, Crous & K. D. Hyde , Fungal Diversity 56 (1): 166. 2012

Fig. 6

Description.

Associated with leaf spot disease of Alnus nepalensis . Teleomorph: Undetermined. Anamorph: Conidiomata formed on PDA pycnidial, scattered, erumpent, subglobose, dark brown, 700–2250 μm diam. Conidiophores indistinct, usually reduced to conidiogenous cells. Conidiogenous cells cylindrical, attenuate towards the apex, hyaline, phialidic, 16.5–34 × 1.5–3 μm. Alpha conidia not observed. Beta conidia aseptate, hyaline, smooth, guttulate, filiform, tapering towards both ends, straight or slightly curved, (27.5 –) 30–35 (– 40.5) × 1.5–2 μm (x ̄ = 32.6 × 1.6 μm, n = 50), L / W = 15.8–23.1. Gamma conidia not observed.

Culture characteristics.

Colonies on PDA at 25 ° C are flocculent, forming concentric zones with undulate margins, initially white, turning pale brownish, and reaching a diameter of 90 mm after 10 d, developing dark brown conidiomata with white conidial masses after 25 d. Colonies on MEA at 25 ° C are flat, spreading, with a smooth entire margin, white, reaching a diameter of 80 mm after 20 d, sterile. Colonies on SNA at 25 ° C are flat, spreading with a feathery margin, white, reaching 80 mm in diameter after 20 d, sterile.

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 (cultures CFCC 70999 and Q 3 B ) .

Notes.

The species concept of Diaporthe amygdali has been revised in recent studies using phylogenetic analysis, GCPSR, and coalescence-based models ( Hilário et al. 2021 b; Dissanayake et al. 2024). Currently, D. amygdali is considered synonymous with D. chongqingensis , D. fusicola , D. garethjonesii , D. kadsurae , D. mediterranea , D. ovoicicola , D. sterilis , and D. ternstroemia ( Hilário et al. 2021 b; Dissanayake et al. 2024). This fungus is widely distributed, inhabiting a range of plant hosts, including Acer spp. , Camellia sinensis , Lithocarpus glabra , Prunus dulcis , Prunus persica , Prunus salicina , Pyrus pyrifolia, Ternstroemia gymnanthera , Vaccinium corymbosum , and Vitis vinifera ( Hilário et al. 2021 b) . In this study, two isolates from leaf spots of Alnus nepalensis clustered with strains of D. amygdali with high support values (Fig. 2 ). Therefore, these two isolates were identified as D. amygdali , which led us to describe Alnus nepalensis as a new host for this fungus.

Figures

Figure 2. Maximum likelihood tree of Diaporthe Section Rudis generated from combined ITS, cal, his 3, tef 1, and tub 2 sequence data. Bootstrap support values ≥ 50 % and Bayesian posterior probabilities ≥ 0.90 are demonstrated at the branches. Isolates from the present study are indicated in blue.

Figure 6. Morphology of Diaporthe amygdali A colony on PDA after 15 d B colony on MEA after 15 d C colony on SNA after 15 d D conidioma formed on PDA E conidiogenous cells E – I beta conidia. Scale bars: 800 µm (D); 10 µm (E – K).