Pleosporales » Dictyosporiaceae » Dictyosporium

Dictyosporium tratense

Dictyosporium tratense J. Yang & K.D. Hyde

 

Index Fungorum number: IF554772; Facesoffungi number: FoF04678

Etymology: Referring to the collecting site in Trat province, Thailand.

 

Saprobic on decaying plant substrates. Sexual morph: Undetermined. Asexual morph: Colonies punctiform, sporodochial, scattered, black, glistening. Mycelium mostly immersed, composed of smooth, septate, branched, hyaline to pale brown hyphae. Conidiophores micronematous, mononematous, septate, cylindrical, hyaline to pale brown, smooth-walled, sometimes reduced to conidiogenous cells. Conidiogenous cells monoblastic, integrated, terminal, determinate, hyaline to pale brown. Conidia (40–)43–54(–57) × (20–)23–32(–36) μm (x̄ = 49.5 × 26 μm, n = 40), acrogenous, solitary, cheiroid, smooth-walled, complanate, yellowish-brown to light brown, consisting of 39–68 cells arranged in 4–6 (mostly 5) closely compact columns, 9–11-euseptate in each column, guttulate; the inner columns nested within the outer columns, the outer columns derived from the basal cell of the conidium; the intermediate columns are derived from the first or second cell of the outer columns; the inner columns derived from the first or second cell of the intermediate columns; usually with 2–3 central columns longest and of equal length, 2–3 peripheral columns shorter and of equal length; sometimes with hyaline globose appendages at the apical cells of outer columns with hyaline cloud-shaped mucilaginous sheath. 

 

Cultural characteristics: Conidia germinating on PDA within 24 h and germ tubes produced from basal cell. Colonies on MEA reaching 5–10 mm diam. in a week at 25 °C, in natural light, circular, with fluffy, dense, pale yellow mycelium in the middle and sparse mycelium in the outer ring on the surface with irregular margin; in reverse, dark yellow to brown in the middle and pale yellow at the margin.

 

Material examined: THAILAND. Trat Province, Amphoe Ko Chang, 12°08'N, 102°38'E, on decaying wood submerged in a freshwater stream, 27 April 2017, Y.Z. Lu, YJT 6-2 (MFLU 18-1042 holotype, HKAS 102133 isotype), ex-type living culture MFLUCC 17-2052 (Additional SSU sequence GenBank MH381761).

 

Notes: Phylogenetic analyses indicated Dictyosporium tratense nested within Dictyosporium and close to D. wuyiense. It is distinguished from the other species in the genus in having a mucilaginous sheath. Morphologically, D. tratense is most comparable to D. elegans in conidial colour and shape, but conidia of the new taxon (40-57 × 20-36 μm) are smaller than those of D. elegans (40-80 × 24-36 μm) (Goh et al. 1999).

 

Freshwater distribution: Thailand (Yang et al. 2018)

 

References

Goh TK, Hyde KD, Ho WH, Yanna (1999) A revision of the genus Dictyosporium, with descriptions of three new species. Fungal Divers 2:65–100

Yang J, Liu JK, Hyde KD, Jones EBG, Liu ZY (2018) New species in Dictyosporium, new combinations in Dictyocheirospora and an updated backbone tree for Dictyosporiaceae. Mycokeys 36:83–105

Fig 1. Dictyosporium tratense (MFLU 18-1042, holotype). a. Colonies on submerged wood, b. Squash mount of a sporodochium, c. Germinated conidium, d–i. Conidia, j, k. Culture j from above, k. from reverse. Scale bars: a = 200 μm, b = 50 μm, c = 30 μm, d–i = 20 μm. (Yang et al. 2018)

 

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