Elsinoe araliae W. Yamam., Sci. Rep. Hyogo Univ. Agric. 3(1): 18 (1957)
Index Fungorum number: IF627255; MycoBank number: MB627255; Facesoffungi number: FoF16128
Associated with scab disease on the leaf, petiole, rachis and fruit of Fatsia japonica (Thunb.) Decne. et Planch., spots subcircular to circular, elliptical to irregular, usually raised and purplish brown at margins, greyish in center, most coalescing and developing typical scab symptoms on older infected tissues, sometimes leading to the distortion of affected organ, local death of severely infected leaves. Sexual morph: Not observed. Asexual morph: Hyphomycetous. Mycelium sparse, mainly internal. Stromata immersed, irregular, pale brown to brown. Dense mass of cells adhering to the surface of lesions, cells swollen, spore-like, brown to dark brown. Conidiophores 10–36 × 3– 5 μm (x̄ = 19.2 × 4.1 μm, n = 20), arising from stromata or hyphae, erect, straight, cylindrical or ampulliform to doliiform, simple, hyaline to brown, 0–1-septate, smooth-walled. Conidiogenous cells integrated, terminal, monophialidic. Conidia 6.5–9 × 3–5 μm (x̄ = 7.9 × 3.9 μm, n = 30), ellipsoid or oval, apex obtuse, aseptate, hyaline, smooth-walled.
Culture characteristics – Colonies on MEA attaining 15–20 mm diameter in 30 days, slowgrowing, raised, cerebriform, compressed and granular protuberance, some pilose aerial mycelium centrally and over other parts of the colony, gelatinous clumps, pale cinnamon, reverse dark tawny, colonies composed of a combination of thickened-walled, pale tawny hyphae and tawny pseudoparenchyma with multi-septate chlamydospores, sporulation not observed. Colonies on OA attaining 15–20 mm diameter in 30 days, slow-growing, circular, flat, leathery, slightly furrowed towards the margin, white to greyish white hyphae centrally, and other parts grow slightly, red to dark red, reverse red to bright red, colonies composed of thin-walled hyaline hyphae, and some hyphae reduced to pigment-producing cells, sporulation not observed. Colonies on PDA attaining 15–20 mm diameter in 20 days, slow-growing, medium raised, cerebriform, comprising and wrinkling the medium, white to greyish white aerial mycelium superficially, mucilaginous drops abundant periphery when late, reverse tawny to dark tawny, colonies subcircular to irregular, composed of pale yellow to bright yellow hyphae, walls medium-thickened, sporulation abundant.
Material examined – China, Sichuan Province, Chengdu City, Wenjiang District, Schoolyard of Sichuan Agricultural University, 103°51′27.6″E 30°42′19.41″N, 526 m, isol. from leaves of Fatsia japonica, 28 Dec. 2019, C.L. Yang, YCL201912003 (SICAU 23-0131), culture (SICAUCC 23-0102).
GenBank numbers – SICAUCC 23-0102 = ITS: PP781968, LSU: PP719618, tef1-α: PQ005617, rpb2: PQ005610
Notes – This new isolate is genetically more closely related to Elsinoe araliae, strongly supported by both Maximum Likelihood (100%) and Bayesian Inference (1.00) (Fig. 25). A comparison of the ITS, LSU, rpb2, and tef1-α nucleotides between E. araliae (MUCC 3490) and the new strain (SICAUCC 23-0102) showed 100% (744/744, 0 gap) similarity for rpb2, 99.8% (531/532, 0 gap) for ITS, 99.9% (735/736, 0 gap) for LSU, and 99.5% (368/370, 0 gap) for tef1-α (Ujat et al. 2023). Morphologically, our new collections fit well with the description of E. araliae (Choi et al. 1998). In this study, we identified the newly isolated strain as a new record E. araliae from Fatsia japonica.
Figure 1 – Elsinoe araliae (holotype, SICAU 23-0131). a, b Symptoms on Fatsia japonica. c, d Cross-section of conidiomata. e, f Conidiogenous cells with developing conidia. g Conidia. h, i Dense mass of cells adhering to the surface of lesions. j Germinating conidia. k–m Front view of colonies on EMA, OA, and PDA. Scale bars: a, b = 5000 μm, c = 200 μm, d–g, j = 10 μm, h, i = 20 μm.