Neohelicosporium xishuangbannaensis Y. R. Xiong, Manawas., & K. D. Hyde, 2024

Xiong, Yinru, Hyde, Kevin D., Lu, Li, Harishchandra, Dulanjalee L., Mapook, Ausana, Xu, Biao, Alotibi, Fatimah & Manawasinghe, Ishara S., 2024, Novel Helicoma and Neohelicosporium (Tubeufiaceae, Tubeufiales) species and two new host records of Helicoma on tropical palms (Arecaceae) from China, MycoKeys 108, pp. 287-315 : 287-315

Neohelicosporium xishuangbannaensis Y. R. Xiong, Manawas., & K. D. Hyde sp. nov.

Fig. 6

Etymology.

Species epithet refers to the location name “ Xishuangbanna ” from where the holotype was collected.

Holotype.

MHZU 23-0156 .

Description.

Saprobic on the rotting petiole of Elaeis guineensis . Sexual morph: Not observed. Asexual morph: Hyphomycetous, helicosporous. Colonies on the substratum superficial, effuse, gregarious, brown. Mycelium composed of partly immersed, partly superficial, brown, septate, unbranched hyphae. Conidiophores 40–125 μm long, 3–6 μm wide (x = 68.4 × 4.4 μm, n = 20), macronematous, mononematous, flexuous, long, cylindrical, branched, septate, smooth-walled. Conidiogenous cells 7–14 μm long, 2.5–5.5 μm wide (x ̄ = 11.2 × 3.9 μm, n = 20), mono- to polyblastic, integrated, sympodial, terminal or intercalary, cylindrical, pale brown, smooth-walled; with denticles, 1.8–3.3 μm long, 1.1–2.3 μm wide (x ̄ = 2.4 × 1.4 μm, n = 20), arising from the juncture portion of two conidiogenous cells as tooth-like and papillate protrusions, mono- to polyblastic, pale brown or hyaline, smooth-walled. Conidia 16.5–20.5 μm diam. (x ̄ = 18.5 μm, n = 40) and conidial filament 1.8–3.2 μm wide (x ̄ = 2.4 μm, n = 40), 90–125 μm long (x ̄ = 107 μm, n = 40), solitary, acropleurogenous, helicoid, rounded at tip, coiled 2–3 ¼ times, 9–13 - septate, becoming loose in water, guttulate, slightly constricted at septa, hyaline to pale brown, smooth-walled.

Culture characteristics.

Conidia germinating on water agar and germ tubes produced from conidia within 12 h. Colonies growing on PDA attaining 2.5 cm diam. after six weeks at 25 ° C, irregular, undulate, umbonate, rough, superficial and partially immersed, brown aerial mycelium mixed with pale brown, deep brown at up and down junction area; reverse brown with deep brown.

Material examined.

China, Yunnan Province, Xishuangbanna City, an unidentified forest beside National Highway 219 (21 ° 93 ' N, 101 ° 24 ' E, 549.6 m elev.), rotting petiole of the Elaeis guineensis , 5 February 2023, Y. R. Xiong and Li Lu, XG 197 ( MHZU 23-0156 , holotype); ex-type, ZHKUCC 24-0119 , other living culture ZHKUCC 24-0120 .

Notes.

Two isolates obtained in this study developed an independent clade in the phylogenetic tree with 77 % ML, 79 % MP bootstrap support and 0.99 BIPP bootstrap support. The nucleotide differences excluding gaps between Neohelicosporium xishuangbannaensis and N. fusisporum ( MFUCC 16-0642 ) are ITS: 2.81 % (15 / 533 base pairs), LSU: 1.06 % (9 / 852 base pairs), tef 1 - α: 2.41 % (22 / 912 base pairs) and rpb 2 sequence is unavailable. Neohelicosporium fusisporum was reported as a sexual and asexual morph by Jayasiri et al. (2017). Neohelicosporium xishuangbannaensis is different from the asexual morph of N. fusisporum ( Jayasiri et al. 2017) in the size of conidia and conidiogenous cells (Table 3 ). In addition, the asexual morph of N. fusisporum ( Jayasiri et al. 2017) has an intercalary conidiogenous cell, while N. xishuangbannaensis has an intercalary (Fig. 6 e, f ) or terminal (Fig. 6 g, h ) conidiogenous cell. Furthermore, the asexual morph of N. fusisporum ( Jayasiri et al. 2017) has denticles with tooth-like or long neck cells, while N. xishuangbannaensis has a denticle with tooth-like and papillate protrusions. Based on these differences, herein we introduce N. xishuangbannaensis as a new species.

Figures

Figure 6. Neohelicosporium xishuangbannaensis (MHZU 23-0156, holotype) a specimen observed b, c colony on decaying Elaeis guineensis d conidiophores e, f intercalary conidiogenous cells g, h terminal conidiogenous cells i – o conidia p germinated conidium q, r culture on PDA from above and reverse. Scale bars: 50 μm (d); 10 μm (e – o); 20 μm (p).