Talaromyces taiwanensis 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-

Talaromyces taiwanensis K. W. Cheng & H. A. Ariyaw. sp. nov.

Fig. 20

Typification.

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, holotype, NTUPPMH 22-219 (Permanently preserved in a metabolically inactive state), ex-holotype NTUPPMCC 22-275 , ex-isotype NTUPPMCC 22-273 to 274, 276 to 285 .

Etymology.

Named after Taiwan, the country where the type specimen was collected.

Description.

Sexual morph undetermined. Asexual morph Conidiophores arose from aerial hyphae, or roping hyphal aggregations, hyaline, smooth but some slightly rough, straight, most mono-verticillate or bi-verticillate, occasionally formed subterminal side branches of mono-verticillate, 5–130 µm. Metulae 10.5–16.5 µm × 2.8–3.2 µm. Phialides most 3–5, flask-shaped, 8.2–15.6 µm × 2.0–2.8 µm, rarely mono-phialides up to 18.2 µm × 3.5 µm. Conidia globose to subglobose, few pyriform, rough surfaces and walls, hyaline in immature, pale green to green in mature, 3.3–4.6 µm × 2.9–4.0 µm (x ̄ = 3.8 × 3.5 µm, L / W ratio = 1.1, n = 50).

Medium dependent growth in 7 / 14 days at 25 ° C (mm).

• CYA 13–15 / 30 – 33; CYAS No growth; MEA 58–60 / 80 – 85; OA 48–50 / 88 – 90; PDA 52–57 / 72 – 75; YESA 37–40 / 65 – 72.

Temperature dependent growth in 7 days (mm).

• CYA / MEA 20 ° C 30–32 / 38 – 40; 30 ° C 19–21 / 55 – 58; 37 ° C 15–16 / 25 – 28.

Culture characteristics.

CYA, 25 ° C, 14 days, obvious sulcate, margin entire, floccose, sporulation none, pale gray to beige at center, soluble pigments absent, exudates clear small droplets; reverse in yellowish brown and caramel at center. MEA, 25 ° C, 14 days, margin slightly irregular and beige, floccose to funiculose, sporulation dense, grayish-green, soluble pigments absent, exudates clear droplets; reverse in cream-buff. OA, 25 ° C, 14 days, margin entire and beige, floccose to funiculose, sporulation dense, olive green, soluble pigments absent, exudates clear small droplets; reverse in buff. PDA, 25 ° C, 14 days, margin entire and whitish, floccose to funiculose, sporulation dense, green, soluble pigments absent, exudates clear droplets; reverse in cream-buff. YESA, 25 ° C, 14 days, margin slightly irregular, floccose, sporulation moderately dense, warm beige, soluble pigments absent, exudates clear small droplets; reverse in warm beige to copper brown.

Notes.

Talaromyces taiwanensis forms a strongly supported clade (100 % / 0.99) with its sister species T. californicus and T. louisianensis in the multi-locus phylogeny (Fig. 19 ). The ex-type strain of T. taiwanensis ( NTUPPMCC 22-275 ) shows over 98.5 % sequence similarity across the ITS, rpb 2, and tub 2 regions when compared to the ex-type strains of T. californicus ( NRRL 58168 ) and T. louisianensis ( NRRL 35823 ). However, a small genetic variation is observed in the cmd A region, where T. taiwanensis exhibits 97.6 % identity (325 / 333 bp, including 1 gap) to these sister species. Morphologically, T. taiwanensis displays conidial structure similar to T. californicus characterized by mono-verticillate and single phialides, a rare phenotypic feature in the T. sect. of Talaromyces (Fig. 20 ; Peterson and Jurjevic 2019). However, T. taiwanensis NTUPPMCC 22-275 formed smaller conidia to its phylogenetically closely related species T. californicus and T. louisianensis (x ̄ = 3.0–5.0 µm × 3.0–4.0 µm versus 4.0–6.0 µm × 4.0–7.0 µm and versus 3.5–5.0 µm × 3.5–5.0 µm). Furthermore, T. taiwanensis demonstrates significantly slower growth (13–15 mm) compared to T. californicus (25–40 mm) and T. louisianensis (35–39 mm) and lacks sporulation on CYA ( Peterson and Jurjevic 2019). Furthermore, these two species were isolated from air in USA and our samples were from serpentine soil in Taiwan ( Peterson and Jurjevic 2019).

Figures

Figure 19. Maximum likelihood (ML) phylogenetic tree based on a concatenated dataset of ITS, cmd A, rpb 2, and tub 2. Species representing section Talaromyces including 113 strains representing 98 taxa were included in the concatenated dataset, with 2127 characters (ITS 536 bp, cmd A 336 bp, rpb 2 843 bp, and tub 2 412 bp) including alignment gaps. The tree was rooted with Talaromyces helicus CBS 335.48 (Section Helici). 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 20. Morphology of Talaromyces taiwanensis NTUPPMCC 22-275. A, D 14 - days-old colony on PDA; B, E 14 - days-old colony on MEA; C, F 14 - days-old colony on CYA; G, H 14 - days-old colony on YESA; I 14 - days-old colony on OA; J – L Conidiophores, phialides, and conidiogenous cells; M Conidia. Scale bars: 20 µm (J, K); 10 µm (L, M).