Neohelicomyces guizhouensis J. Ma, Y. Z. Lu & K. D. Hyde, 2024

Ma, Jian, Gomdola, Deecksha, Boonmee, Saranyaphat, Shen, Hong-Wei, Tang, Xia, Zhang, Li-Juan, Lu, Yong-Zhong & Hyde, Kevin D., 2024, Three new species of Neohelicomyces (Tubeufiales, Tubeufiaceae) from freshwater and terrestrial habitats in China, MycoKeys 105, pp. 317-336 : 317-336

Neohelicomyces guizhouensis J. Ma, Y. Z. Lu & K. D. Hyde sp. nov.

Fig. 2

Etymology.

The epithet “ guizhouensis ” refers to Guizhou Province, from where the specimen was collected.

Holotype.

HKAS 134924 .

Description.

Saprobic on decaying wood in a freshwater habitat. Sexual morph Unknown from natural habitat. Asexual morph Hyphomycetous, helicosporous. Colonies on natural substrate superficial, effuse, gregarious, white to light pink. Mycelium semi-immersed, hyaline to pale brown, septate, branched hyphae, smooth, comprising glistening conidial mass. Conidiophores 78–288 μm long, 4–6 μm wide (x ¯ = 179.5 × 5 μm, n = 20), macronematous, mononematous, erect, flexuous, cylindrical, sometimes branched, septate, hyaline to pale brown, smooth, thick-walled. Conidiogenous cells 9–18 μm long, 2.5–4.5 μm wide (x ¯ = 14 × 3.5 μm, n = 25), holoblastic, mono- to poly-blastic, integrated, sympodial, intercalary or terminal, cylindrical, with a denticulate protrusion, truncate at apex after conidial secession, hyaline to pale brown, smooth-walled. Conidia solitary, acropleurogenous, helicoid, rounded at the tips, 18–21.5 μm in diameter and conidial filament 2–2.7 μm wide (x ¯ = 20 × 2.3 μm, n = 20), 94.5–148.5 μm long (x ¯ = 126.5 μm, n = 30), multi-septate, coiled 2 ¾ – 3 ½ times, becoming loosely coiled in water, guttulate, hyaline, smooth-walled.

Culture characteristics.

Conidia producing germ tubes on PDA within 9 hours of incubation at 25 ° C. Colonies on PDA are circular with flat surface and undulate edge, reaching 40 mm diameter after 45 days of incubation at 25 ° C, top view of colony pale pink to brown, reverse brown to dark brown.

Material examined.

China, Guizhou Province, Zunyi City, Renhuai City, Daba Town, on decaying wood in a freshwater habitat, 17 August 2021, Jian Ma, RH 4 ( HKAS 134924 , holotype; GZAAS 23–0619 , isotype), ex-type living cultures GZCC 23–0725 ; Ibid., RH 4.1 ( GZAAS 23–0620 , paratype), living culture GZCC 23–0726 .

Notes.

The newly-identified strains ( GZCC 23–0725 and GZCC 23–0726 ) are phylogenetically grouped with N. denticulatus , N. deschampsiae , N. pallidus and N. pandanicola (Fig. 1 ). However, it is most closely related to N. deschampsiae ( CPC 33686) phylogenetically and a comparison of polymorphic nucleotides across ITS and LSU sequences between GZCC 23–0725 and N. deschampsiae ( CPC 33686) revealed nucleotide base disparities of 34 / 546 bp (6.3 %, including fourteen gaps) and 4 / 860 bp (0.5 %, including 0 gap), respectively. Morphologically, N. guizhouensis is most similar to N. dehongensis in having macronematous, mononematous, erect, flexuous branched conidiophores and solitary, helicoid, hyaline conidia ( Dong et al. 2020). However, N. dehongensis can be delineated from N. guizhouensis by its longer conidia (145–210 μm vs. 94.5–148.5 μm) and wider conidial filaments (20–25 μm vs. 18–21.5 μm) ( Dong et al. 2020). Therefore, based on the findings from both molecular and morphological evidence, we propose N. guizhouensis as a new species.

Figures

Figure 1. Phylogenetic tree generated from Maximum Likelihood (ML) analysis, based on the combined ITS, LSU, tef 1 α and rpb 2 sequence data. Bootstrap support values of ML equal to or greater than 75 % and Bayesian posterior probabilities (PP) equal to or greater than 0.95 are given near the nodes as ML / PP, respectively. Helicotubeufia hydei (MFLUCC 17–1980) and H. jonesii (MFLUCC 17–0043) were selected as outgroup taxa. The new species are typed in bold red; “ T ” denotes ex-type strains.

Figure 2. Neohelicomyces guizhouensis (HKAS 134924, holotype) a, b colonies on the host surface c, d conidiophores, conidiogenous cells and conidia e – g conidiogenous cells h – l conidia m germinated conidium n, o surface and reverse colonies on PDA after 45 days of incubation at 25 ° C. Scale bars: 50 μm (c); 30 μm (d); 10 μm (e, g, m); 5 μm (f, h – l).