Dictyosporium cycadicola W.H. Tian, K.D. Hyde & Maharachch., in Tian, Liu, Jin, Chen, Zhou, Wu, Su, Guo, Wanasinghe, Hyde, Liu & Maharachchikumbura, Mycosphere 15(1): 1803 (2024)

Index Fungorum number: IF 854679; MycoBank number: MB 854679; Facesoffungi number: FoF16269

Etymology – Named after the host genus from which the holotype was collected, Cycas.

Holotype – HKAS 134909

Saprobic on dead stems of Cycas revoluta. Asexual morph: Hyphomycetous. Colonies on a natural substrate were punctiform, sporodochial, scattered, dark and dark brown, and flaky. Mycelium comprised partly immersed, partly superficial, brown, septate, and branched hyphae. Conidiophores micronematous, reduced to conidiogenous cell. Conidiogenous cells 10–22 × 1.6–4 μm (x̅= 14.5 × 3 μm, n = 20), holoblastic, cylindrical, sometimes flat at base. Conidia 18.5–33 × 12.5–21 μm (x̅= 26.5 × 16 μm, n = 35), solitary, oval to ellipsoid, brown to dark brown, cheiroid, not complanate, composed of 4–5 rows, inflated, rows not separating, each row consisting of 4–10 cells, guttulate, without appendages. Sexual morph: Undetermined.

Material examined – China, Sichuan Province, Chengdu city, University of Electronic Science and Technology of China, N 30°45’24”, E 103°55’54”, elevation 480 m, 12 June 2022, on dead stems of Cycas revoluta, W.H. Tian U08_1 (HKAS 134909, holotype).

GenBank numbers – ITS: PP740382, LSU: PP740388, SSU: PP740394, tef1-α: PP776570

Notes – Phylogenetic analyses of combined ITS, LSU, SSU and tef1-α sequence data showed that our collection (HKAS 134909) sister to the type strain of Dictyosporium krabiense (MFLU 16- 1890). Morphologically, our collection (HKAS 134909) differs from D. krabiense by larger conidiogenous cells (10–22 × 1.6–4 μm vs. 2–3.5 × 2–3 μm), longer conidia (18.5–33 × 12.5–21 μm vs. 14–17 × 15–20 μm), without appendages vs. 1–2 appendages, and more cells in the conidia row (4–10 cells vs. 4–6 cells) (Tibpromma et al. 2018). The type strain of Dictyosporium krabiense lacks an ITS sequence (Tibpromma et al. 2018). Based on other pairwise nucleotide comparisons, our collection (HKAS 134909) differs from the type strain of D. krabiense (MFLU 16-1890) by 1/809 bp (no gaps) in LSU, 6/981 bp (gaps: 6/981 bp) in SSU, and 18/926 bp (gaps: 3/926 bp) in tef1-α. Based on their morphological differences, we introduce D. cycadicola as a new species of Dictyosporium.

Figure 1 – Dictyosporium cycadicola (HKAS 134909, holotype). a Specimen. b, c Colonies on dead stems of Cycas revoluta. d–f Conidiogenous cells and conidia. g–i Conidia. Scale bars: d–i = 10 μm.