Pyrenochaetopsis paucisetosa N. Valenzuela-Lopez, J. F. Cano, J. Guarro & A. M. Stchigel (2018)

Cheng, Kai-Wen, Yang, Jiue-in, Srimongkol, Piroonporn, Stadler, Marc, Karnchanatat, Aphichart & Ariyawansa, Hiran A., 2025, Fungal frontiers in toxic terrain: Revealing culturable fungal communities in Serpentine paddy fields of Taiwan, IMA Fungus 16, pp. e 155308-e 155308 : e155308-

Pyrenochaetopsis paucisetosa N. Valenzuela-Lopez, J. F. Cano, J. Guarro & A. M. Stchigel (2018)

Fig. 7

Description.

Sexual morph undetermined. Asexual morph Conidiomata 128–219 µm, pycnidial, globose to subglobose, dark brown, ostiolate, with dark brown, septate setae, superficial on WA and carnation leaves. Pycnidial wall textura angularis, septate setae, brown, pseudoparenchymatous cells. Conidiogenous cells hyaline, phialidic, smooth-walled, 3.6–5.0 µm × 2.9–4.1 µm (x ̄ = 4.1 × 3.5 µm, n = 30). Conidia hyaline, cylindrical to ellipsoidal, aseptate, with 2 small guttules, 3.7–4.7 µm × 1.5–2.1 µm (x ̄ = 4.2 × 1.8 µm, L / W ratio = 2.4, n = 30).

Culture characteristics.

Colony exhibit slow growth, reaching 28 mm diam with pale gray, floccose surface, smooth margins, and medium-gray on the reverse side of the colony.

Material examined.

TAIWAN • Wanrung Township , Hualien County, 23°42'41.2"N, 121°24'41.8"E, serpentine soil in rice field, 2 nd November 2022, K. W Cheng, living culture NTUPPMCC 22-227 .

Notes.

In the present study, strain NTUPPMCC 22-227 identified as Pyrenochaetopsis paucisetosa , clustering in a strongly supported clade (100 % / 1.00) with the type strain of Py. paucisetosa ( UTHSC DI 16-193 ) in multi-gene phylogeny analysis (Fig. 8 ; Valenzuela-Lopez et al. 2018). Previous reports indicate that Py. paucisetosa has been isolated from a human toe nail in USA ( Valenzuela-Lopez et al. 2018) and from freshwater sediment in Korea ( Goh et al. 2020). The culture characteristics of NTUPPMCC 22-227 on PDA were similar to those of the ex-holotype of Py. paucisetosa ( UTHSC DI 16-193 ). However, the conidia of Py. paucisetosa NTUPPMCC 22-227 in our study were more elongated than previous reports (x ̄ = 4.2 × 1.8 µm versus 3.6 × 1.9 µm) (Fig. 7 ; Valenzuela-Lopez et al. 2018; Goh et al. 2020). Furthermore, this is the first record of Py. paucisetosa in Taiwan, as well as its first occurrence in paddy field soil.

Figures

Figure 7. Morphology of Pyrenochaetopsis paucisetosa NTUPPMCC 22-227. A, B 14 - days-old colony on PDA; C Conidiomata; D Squashed conidiomata; E Conidiogenous cells; F – H Conidia. Scale bars: 0.2 mm (C); 0.1 mm (D); 10 µm (E, F); 5 µm (G, H).

Figure 8. Maximum likelihood (ML) phylogenetic tree based on a concatenated dataset of ITS, LSU, rpb 2, and tub 2. In total, 52 strains representing 29 taxa were included in the concatenated dataset, with 2453 characters (ITS 451 bp, LSU 845 bp, rpb 2 815 bp, and tub 2 342 bp) including alignment gaps. The tree was rooted with Neopyrenochaetopsis hominis CBS 143033. MLB ≥ 70 % and BPPs ≥ 0.95 were shown at each node; values lower than these thresholds are indicated by a hyphen (–). The scale bar indicates the number of estimated substitutions per site. The strains introduced in this study are in red and novel species are in bold. The ex-type strains are marked with T.