Distoseptispora narathiwatensis O. Karimi, Q.R. Li & K.D. Hyde, 2024

Karimi, Omid, Chethana, K. W. Thilini, de Farias, Antonio R. G., Asghari, Raheleh, Kaewchai, Saithong, Hyde, Kevin D. & Li, Qirui, 2024, Morphology and multigene phylogeny reveal three new species of Distoseptispora (Distoseptisporales, Distoseptisporaceae) on palms (Arecaceae) from peatswamp areas in southern Thailand, MycoKeys 102, pp. 55-81 : 55

Distoseptispora narathiwatensis O. Karimi, Q.R. Li & K.D. Hyde sp. nov.

Fig. 4

Etymology.

The epithet " narathiwatensis " refers to Narathiwat Province, where the holotype was collected.

Holotype.

MFLU 23-0278.

Description.

Saprobic on dead petiole of Eugeissona tristis in peatswamp forest. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies superficial, effuse, hairy, gregarious, brown. Mycelium immersed to superficial, composed of septate, branched, pale brown hyphae. Conidiophores 27-155 × 3-6.5(-7) μm (x̄ = 104 × 5 μm, n = 50), macronematous, mononematous, cylindrical, straight or flexuous, occasionally slightly curved in the middle and near the base and the apex, up to 10 septa, slightly constricted at septa, unbranched, brown, thin-walled, smooth, often containing inflated or constricted cells at the apex or middle, sometimes percurrent with annellations. Conidiogenous cells 7-17 × 4-5.5 μm (x̄ = 12.5 × 5 μm, n = 30), holoblastic, mono- to polyblastic, integrated, determinate, terminal and intercalary, subcylindrical, brown, smooth. Conidia 12-38 × 4.5-8 μm (x̄ = 27 × 6.5 μm, n = 30), secession schizolytic, solitary or occasionally catenate, dry, thin-walled, smooth, subcylindrical to obclavate to conical, straight or curved, 1-7-distoseptate, slightly constricted at septa, olivaceous to brown, apex rounded, truncated base with slightly pigmented scar, often the primary cells of conidia are narrower than the second ones which are often inflated.

Culture characteristics.

Colonies grown on PDA, reaching 50 mm in diameter after 15 days at 25 °C, under dark conditions, circular, entire margin, well-defined margin, low convex, dull surface, felted, dense, mycelium mostly superficial, without pigment diffusion and sporulation, medium brown to reddish-brown with dark brown edge on the top, reverse-side dark brown to black.

Material examined.

Thailand. Narathiwat Province: Yi-ngo District, peatswamp forest, on dead petiole of Eugeissona tristis , 06 April 22, Omid Karimi , 35Y (MFLU 23-0278, holotype); ex-type culture MFLUCC 23-0215, additional living culture MFLUCC 23-0216 .

Notes.

Distoseptispora narathiwatensis (MFLU 23-0278) is similar to D. saprophytica (MFLU 18-1568), but it can be distinguished in having longer and wider conidiophores (27-155 × 3-6.5 (-7) μm vs. 50-140 × 3.2-4.2 μm) and conidiogenous cells (7-17 × 4-5.5 μm vs. 5-11.5 × 3-4.5 μm). In D. narathiwatensis (MFLU 23-0278), the conidiophore is slightly curved at the base, middle and near the top in contrast to D. saprophytica (MFLU 23-0278), which is characterised by sharp curving near the base; also in D. narathiwatensis , the conidiophore cells are often inflated or constricted at the apex or middle which is not observed in D. saprophytica ( Dong et al. 2021). Conidiogenous cells of D. narathiwatensis are terminal and intercalary and their conidia are not acrogenous as in D. saprophytica . The primary cell in the conidium is often narrower than the second one and the second cell is often inflated, which is not observed in D. saprophytica . The BLAST search against the GenBank showed that the ITS and rpb2 sequences of the new isolate, D. narathiwatensis (MFLUCC 23-0215), share 98.33% similarity across 100% sequence coverage and 98.63% similarity across 78% sequence coverage with D. saprophytica (MFLUCC 18-1238), respectively. In a BLAST search against GenBank, the LSU and tef1-α sequences of D. narathiwatensis (MFLUCC 23-0215) share 99.3% similarity across 85% sequence coverage and 94.12% similarity across 94% sequence coverage with D. palmarum (MFLU 18-0588), respectively. However, D. palmarum is distinguished in having longer (12-38 μm vs. 35-180 μm), elongated, greenish-black to brown conidia ( Hyde et al. 2019). Based on a pairwise comparison of ITS and LSU nucleotides, D. narathiwatensis (MFLUCC 23-0215) differs from D. saprophytica (MFLUCC 18-1238) by 22/580 bp (3.8%), 16/870 bp (1.8%) differences, respectively (without including gaps). Therefore, we introduced D. narathiwatensis (MFLU 23-0278) as a novel species, based on the morphological evidence and according to the species delimitation guidelines proposed by Chethana et al. (2021) and Maharachchikumbura et al. (2021).

Figures

Figure 4. Distoseptispora narathiwatensis (MFLU 23 - 0278, holotype) a host material b colonies on the substrate c-e conidiophores and conidia f conidiogenous cell g-j conidia k, l culture on PDA. Scale bars: 100 μm (b); 50 μm (c-e); 10 μm (f-j).