Epicoccum maxima Manawas., Q.L. Tan & Y.Xia Zhang [as ‘Epicoccum maximum‘], in Cao et al., (2025)

Index Fungorum number: IF 903595; MycoBank number: MB 664949;Facesoffungi number: FoF 17681; Figs. 1, 2

Etymology – epithet refers to the host, Citrus maxima from which the fungus was isolated.

Holotype – ZHKUCC 24–1069.

Endophytic on Citrus maxima, sexual morph: not observed. Asexual morph: after 4 weeks on OA medium, Pycnidia 80–152 × 70–125(–140) µm (mean = 125 × 110 µm, n = 30), transparent to black, solitary or aggregated, ovoid or subspherical, sometimes pear-shaped, surface or semi-buried in the medium. The walls of pycnidium are composed of elongated and equal diameter cells, with 3–4 layers of cell layers, including 2–3 layers of brown outer layer, with a thickness of 17–22 µm. Conidiophore: not observed. Conidiogenus cells: not observed. Conidia ellipsoid to cylindrical, smooth, hyaline, 7.2–9.3 × 3.2–5.0 µm (mean = 8 × 4.1 µm, n = 50).

Culture characteristics – Cultivate on OA medium for 7 days, with a colony diameter of 72 mm (n = 5). The edge of the colony is regular, the hyphae are closely attached, and the colony is white to gray in the center, white to gray on the back, with a slight yellow color. Cultivate on PDA medium for 7 days and cover the plate with mycelium. The white mycelium is lush, dense, with regular edges, and the back is white to slightly orange yellow. Cultivate on MEA medium for 7 days with a colony diameter of 75 mm (n = 5). The edge of the colony is regular, with dense white hyphae, slightly orange in the middle, radiating, and white to orange on the back.

Material examined – CHINA, Guangdong Province, Guangzhou, Shaoguan City, Renhua County, Daqiao Town, Changba Village, Jin Zhe Yuan Ecological Agriculture Co. LTD. On Citrus maxima, 25 August 2021, Ishara S. Manawasinghe, ZHKUCC 24–1069 (holotype), living cultures ZHKUCC 24–1070, ZHKUCC 24–1071 and ZHKUCC 24–1072.

GenBank – ZHKUCC 24–1069: PV486802 (ITS), PV486804 (LSU), PV494564 (rpb2), PV494562 (tub2).

Notes – In the multigene phylogenetic analysis constructed by ITS, LSU and rpb2 and tub2 (Fig. 2), the species in this study formed an independent branch, with a particular sister relationship to E. poaceicola, with 99% ML bootstrap support and 1.0 BYPP value. In terms of morphological identification, the PDA culture medium of the strain in this study covered the plate at 25 °C, and the growth rate was faster than the E. poaceicola 51 mm (Thambugala et al. 2017). The conidia in this study ranged from 7.2–9.3 × 3.2–5.0 µm (mean = 8 × 4.1 µm) compared to E. poaceicola (2–)3–5.7 × 1.8–3 µm (mean = 4 × 2.2) µm larger. Based on morphological characteristics and multigene phylogenetic analysis, the strain in this study was identified as a new species.

Figure 1 – Epicoccum maxima (ZHKUCC 24–1069, holotype). a, b Colony on OA (front and reverse). c, d Colony on MEA (front and reverse). e, f Colony on PDA (front and reverse). g, i Pycnidium forming on OA. j, h Section of pycnidium. k Conidia. Scale bars: g–k = 10 µm.

Figure 2 – The Maximum Likelihood consensus tree inferred from the combined ITS, LSU, rpb2 and tub2 sequences of Epicoccum, Remotididymella and other closely related genera in Didymellaceae. Bootstrap support values for Maximum Likelihood (ML, first value) equal to or greater than 75% and Bayesian posterior prob abilities from MCMC analyses (BYPP, second value) equal to or greater than 0.95 are given above the nodes. The scale bar indicates expected changes per site. The tree is rooted to Neodidymelliopsis xanthina (CBS 168.70) and Neodidymelliopsis achlydis (CBS 256.77). Type strains are indicated with “T”. The newly generated sequences are indicated in red.