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

Fig. 2

Etymology.

The epithet ‘‘ arecacearum ’’ refers to host family, Aceraceae .

Holotype.

MFLU 23-0276.

Description.

Saprobic on submerged rachis of Licuala paludosa in peatswamp forest. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies gregarious or scattered, effuse, hairy, dark brown to black. Mycelium mostly immersed, composed of branched, septate, smooth hyphae. Conidiophores 70-140 × 5.1-6.3 µm (x̄ = 110 × 5.5 µm, n = 20), macronematous, mononematous, unbranched, erect, straight or flexuous, cylindrical, smooth, thick-walled, brown, 4-7 septa, sometimes consists a swollen cell in the middle or towards the apex. Conidiogenous cells 13-25 × 4.5-6 µm (x̄ = 17 × 5 µm, n = 20), monoblastic or polyblastic, terminal or subterminal, determinate, cylindrical, brown. Conidia 25-60 × 7-17 µm (x̄ = 44 × 10 µm, n = 30), acrogenous, solitary, cylindrical, obclavate to obpyriform or irregular, straight or curved, 4-10-distoseptate, brown, thick-walled, smooth, round apex, truncated base, sometimes with percurrent regeneration forming a secondary conidium from the conidial apex.

Culture characteristics.

Colonies grown on PDA, reaching 50 mm in diameter after 15 days at 25 °C, under dark conditions, circular, fimbriate edge, flat, dull surface, radiating outwards, felted, medium dense, without pigment diffusion and sporulation, brown on the top, reverse dark brown to black.

Material examined.

Thailand. Narathiwat Province: Yi-ngo District , peatswamp forest, on submerged rachis of Licuala paludosa , 06 April 2022, Omid Karimi, S 5PP3SG (MFLU 23-0276, holotype); ex-type culture MFLUCC 23-0211, additional living culture MFLUCC 23-0212 .

Notes.

Morphologically, our proposed new species is similar to Distoseptispora dehongensis W. Dong, H. Zhang & K.D. Hyde and D. obpyriformis Z.L. Luo & H.Y. Su in having macronematous, mononematous, unbranched, erect, straight or flexuous, cylindrical, septate conidiophores, terminal, determinate, cylindrical, brown conidiogenous cells and acrogenous, distoseptate, straight or curved conidia ( Luo et al. 2018; Hyde et al. 2019). However, our isolate differs from D. dehongensis (HKAS 101738) in having longer and wider conidiophores (70-140 × 5.1-6.3 µm vs. 45-80 × 4-5 µm), with swollen cells, longer and wider conidia (25-60 × 7-17 µm vs. 17-30 × 7.5-10 µm) and more distosepta (4-10-distoseptate vs. 3-5-distoseptate). Distoseptispora arecacearum (MFLU 23-0276) differs from D. obpyriformis (MFLU 18-0476) in having conidiophores with swollen cells and shorter conidia (25-60 µm vs. 53-71 µm) ( Luo et al. 2018). The BLASTn searches of the ITS sequence of D. arecacearum (MFLUCC 23-0211) resulted in D. aquatica Z.L. Luo, H.Y. Su & K.D. Hyde (MFLUCC 18-0646) with 92.21% similarity across 100% of the query sequence coverage, while the LSU sequence of D. arecacearum has 99.09% similarity across 100% of the sequence coverage with D. phangngaensis J. Yang, Maharachch. & K.D. Hyde (MFLUCC 16-0857). Distoseptispora arecacearum (MFLU 23-0276) is easily distinguishable from D. aquatica (HKAS 83991) in having longer conidiophores (70-140 µm vs. 29-41 μm) and shorter conidia (25-60 µm vs. 110-157 µm) with less distosepta (4-10-distoseptate vs. 15-28-distoseptate) ( Su et al. 2016). Distoseptispora arecacearum (MFLU 23-0276) differs from D. phangngaensis (MFLU 17-0855) in having longer conidiophores (70-140 µm vs. 18-30(-40) μm) and shorter conidia (25-60 µm vs. 165-350 µm) ( Yang et al. 2018). Therefore, we introduced D. arecacearum (MFLU 23-0276) as a novel species, based on morphological and phylogenetic analyses.

Figures

Figure 2. Distoseptispora arecacearum (MFLU 23 - 0276, holotype) a host material b colonies on the substrate c-e conidiophores and conidia f-i conidia j, k culture on PDA. Scale bars: 200 µm (b); 50 µm (c-e); 10 µm (f-i).