Sarocladium serpentinicola K. W. Cheng & H. A. Ariyaw., 2025

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-

Sarocladium serpentinicola K. W. Cheng & H. A. Ariyaw. sp. nov.

Fig. 28

Typification.

TAIWAN • Guanshan Township , Taitung County, 23°02'14.8"N, 121°11'22.6"E, serpentine soil in rice field, 3 rd November 2022, K. W. Cheng, holotype, NTUPPMH 22-223 (Permanently preserved in a metabolically inactive state), ex-holotype NTUPPMCC 22-290 .

Etymology.

Named after the serpentine soil from which the species was isolated.

Description.

Sexual morph undetermined. Asexual morph Conidia were observed on WA. Conidiophores solitary, hyaline, straight to slightly flexuous, smooth-walled, arising from hyphal ropes or vegetative hyphae. Phialides subulate, hyaline, wide at the base, with, 23–32 µm long. Schizophialides not observed. Conidia unicellular, cylindrical with rounded ends, hyaline, smooth-walled, 1 - celled, few with inconspicuous 1 to 2 guttules on the end (s), sometimes aggregated in clusters forming a slimy head, 3.2–5.5 µm × 1.2–1.8 µm (x ̄ = 4.3 × 1.5 µm, L / W ratio = 2.92, n = 30). Adelophialides observed, 3.6–8.8 µm long and sporulated obvious guttules and larger conidia, 3.8–7.0 µm × 1.6–2.5 µm (x ̄ = 5.3 × 2.0 µm, L / W ratio = 2.73, n = 30).

Culture characteristics.

Colony exhibit slow growth, reaching 30 mm diam with flat, pale orange, slightly wrinkled in the center, slimy, and smooth margin. The reverse side of the colony displayed similar characteristics.

Notes.

Sarocladium serpentinicola introduced in this study forms a distinct clade with moderately support (82 % / 0.91) based on multi-locus phylogenetic analysis (Fig. 27 ). Moreover, S. serpentinicola forms significant genetic divergence to its closer relatives, ex-type strain of S. pseudostrictum ( CBS 137660 ) with 96.0 % identity in the ITS region (460 / 474 bp, including 5 gaps) and 96.2 % identity in the tef- 1 gene (777 / 808 bp). It also exhibits notable divergence from S. formosanum , another novel species described in this study, with 91.3 % identity in the rpb 2 gene (648 / 710 bp) and 96.9 % identity in the tef- 1 gene (783 / 808 bp). S. serpentinicola NTUPPMCC 22-290 can be distinguished from its close relatives S. pseudostrictum and S. graminicola by the presence of adelophialides and the production of larger conidia from these structures (Fig. 28 ; Giraldo et al. 2015; Anjos et al. 2020).

Figures

Figure 27. Maximum likelihood (ML) phylogenetic tree based on a concatenated dataset of ITS, LSU, rpb 2, and tef- 1. In total, 45 strains representing 38 taxa were included in the concatenated dataset, with 2821 characters (ITS 497 bp, LSU 779 bp, rpb 2 734 bp, and tef- 1 811 bp) including alignment gaps. The tree was rooted with Parasarocladium breve CBS 150.62. 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 28. Morphology of Sarocladium serpentinicola NTUPPMCC 22-290. A, B 14 - days-old colony on PDA; C, D Conidiophores and phialides; E, F Adelophialides; G Conidia. Scale bars: 10 µm (C – G).