Dictyocheirospora taiwanensis Tennakoon, C.H. Kuo & K.D. Hyde, Fungal Divers. 96, 27 (2019)
Index Fungorum number: IF556309; MycoBank number: MB556309; Facesoffungi number: FoF05964
Saprobic on submerged decaying wood. Asexual morph: Hyphomycetous. Colonies superficial, punctiform, dark brown. Mycelium immersed, composed of subhyaline, smooth, thinwalled, septate hyphae. Conidiophores 10.2–10.4 × 3.1–3.3 µm, micronematous, mononematous, subhyaline, smooth, thin-walled. Conidiogenous cells 7.5–8.6 × 2.3–3.6 µm, holoblastic, integrated, terminal, determinate, cylindrical, brown, smooth, thin-walled. Conidia 50–80 × 17–26 µm (x̅ = 61.3 × 22.9 µm, n = 50), solitary, cheiroid, ellipsoid to clavate, rounded at the apex, not complanate, brown to brownish-red, composed of 6 rows of cells, row digitate, cylindrical, inwardly curved at the tip, arising from a basal cell, each row with 10–12 cells, euseptate, slightly constricted at the septum, unseparated when in water, and the top is tightly clustered together. Sexual morph: Undetermined.
Culture characteristics – Conidia germinating on PDA within 12 h, and germ tubes produced from the base. Colonies on PDA reaching 30 mm diameter after 3 weeks of incubation at room temperature. Mycelium dry, dense, colonies on the surface of PDA, with regular edges, flat surface, white to grey. Reverse orange, with dark brown in the center, smooth, split from the center.
Material examined – China, Yunnan Province, Wenshan Zhuang and Miao Autonomous Prefecture, Bamei Town, on submerged decaying wood, 7 February 2022, W.P. Wang, S-3502 (HKAS 131365), living culture KUNCC 23–13720.
Notes – The phylogenetic analysis showed that our new strain (KUNCC 23–13720) clusters in Dictyocheirospora and sister to D. taiwanensis (MFLUCC 17–2654 and SDBR-CMU458) with low support (Fig. 8). Our new collection is similar to the holotype of D. taiwanensis (MFLUCC 17–2654) in having ellipsoid, cheiroid, acomplanate conidia, and the conidial rows are cylindrical, arising from a basal cell, constricted at septum with a similar number cells of conidial row (10–12 vs. 10–13) and without appendages (Hyde et al. 2019). Comparison of the ITS sequence of our new collection and the ex-type strain of D. taiwanensis showed 99.4% (499/502 bp, two gaps) similarity. Dictyocheirospora taiwanensis was introduced by Hyde et al. (2019) on decaying wood of Macaranga tanarius (Euphobiaceae) in Taiwan, China. Tennakoon et al. (2023) reported D. taiwanensis on decaying stem of Ficus benjamina (Moraceae) in Thailand. We therefore identified the new collection as D. taiwanensis, and this is the first report of this species from freshwater habitat.
Figure 1 – Dictyocheirospora taiwanense (HKAS 131365). a Colonies on the substratum. b–e, i Conidiogenous cells with conidia. f–h Conidia. j Germinating conidium. k, l Colonies on PDA from surface and reverse. Scale bars: b = 30 µm, c–j = 20 µm.
Figure 2 – RAxML tree based on analysis of Dictyosporiaceae that combined ITS, LSU, and tef1-α dataset. The combined analyses include 81 strains with 2181 characters, including gaps (ITS: 498 bp, LSU: 814 bp, and tef1-α: 869 bp). Bootstrap support values for maximum likelihood (ML) greater than 75% and Bayesian posterior probabilities greater than 0.95 are indicated above branches as ML/PP. The tree is rooted with Murilentithecium clematidis (MFLUCC 14–0561 and MFLUCC 14– 6545 0562). The new collections are indicated in red. Ex-type strains are indicated with “T” after the strain number.