Pyrenochaetopsis oryzicola S. Absalan, S. Lumyong & K. D. Hyde (2024)

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 oryzicola S. Absalan, S. Lumyong & K. D. Hyde (2024)

Fig. 9

Description.

Sexual morph undetermined. Asexual morph Sporulation difficult on PDA and MEA, conidiomata produced on carnation leaves and on the surface or submerged in WA. Conidiomata 140–196 µm, pycnidial, brown, globose to subglobose, ostiolate, superficial on WA and carnation leaves, with dark brown, septate setae. Pycnidial wall textura angularis to globulosa, brown, pseudoparenchymatous cells. Conidiogenous cells hyaline, phialidic, smooth-walled, and hard to distinguish from the pycnidial wall 3.3–5.6 µm × 3.0–4.6 µm (x ̄ = 4.4 × 3.5 µm, n = 30). Conidia hyaline, cylindrical to ellipsoidal, aseptate, with 2 small but obvious guttules, 3.6–5.1 µm × 1.7–2.5 µm (x ̄ = 4.3 × 2.2 µm, L / W ratio = 2.03, n = 50).

Culture characteristics.

Colony reaching 45 mm diam with greenish-gray, flat, velvety to floccose surface and smooth margins, and similar to reverse side of the colony.

Material examined.

TAIWAN • Wanrung Township , Hualien County, 23°42'40.3"N, 121°24'48.2"E, serpentine soil in rice field, 2 nd November 2022, K. W Cheng, living culture NTUPPMCC 22-228 to 242 .

Notes.

Pyrenochaetopsis oryzicola was originally reported from dead panicles of Oryza sativa in paddy fields in Thailand ( Absalan et al. 2024). In the present, in both single- and multi-gene phylogenetic analyses showed that strains from NTUPPMCC 22-228 to 242 isolated in this study, grouped with the clade containing the ex-type strain of Py. oryzicola ( MFLUCC 24-0042 ) (Fig. 8 ). Consequently, these strains were identified as Pyrenochaetopsis oryzicola . Their culture characteristics on PDA, along with conidial morphology, were consistent with those of the epitype of Py. oryzicola ( MFLU 24-0319 ). However, the conidiogenous cells of Py. oryzicola NTUPPMCC 22-229 isolated in our study were larger than those reported in the previous study (x ̄ = 4.5 × 3.5 µm versus 1.5 × 1.0 µm) (Fig. 9 ; Absalan et al. 2024).

Figures

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.

Figure 9. Morphology of Pyrenochaetopsis oryzicola NTUPPMCC 22-229. A, B 14 - days-old colony on PDA; C Conidiomata; D Squashed conidiomata; E Conidiogenous cells; F Conidia. Scale bars: 0.5 mm (C); 0.1 mm (D); 10 µm (E, F).