Penicillium chiangmaiense Thitla, Monkai, Lumyong & Hongsanan, 2025

Penicillium chiangmaiense Thitla, Monkai, Lumyong & Hongsanan sp. nov.

Etymology.

The specific epithet “ chiangmaiense ” refers to the type locality “ Chiang Mai Province, Thailand ”.

Holotype.

Thailand • Chiang Mai Province, Mae Rim District, Mae Sa , on soil in the forest dump-sites, 27 June 2024, T. Thitla & J. Monkai; VR 005 ( SZU 25-006 About SZU , holotype); ex-type living culture, MBSZU 24-009 , dried culture permanently preserved in a metabolically inactive state, SZU 25-006 About SZU .

Colony diam.

(in mm) 7 days, 25 ° C: CREA 40–44 , CYA 50–52, CYAS 35–38 , CZ 48–49, DG 18 34–39, MEA 47–51, MEAbl 51–53, OA 53–54, PDA 49–50 and YES 32–38. 7 days, 30 ° C: CYA 59–61. 7 days, 37 ° C: CYA 55–56.

Culture characteristics.

Colonies at 25 ° C for 7 days on CREA thin colonies; acid production absent (Fig. 6 A View Figure 6 ). Colonies on CYA and CYAS wrinkled texture, velvety, circular, flat, entire margin; white mycelia; soluble pigment absent; reverse light brown (Fig. 6 B, C View Figure 6 ). On CZ, thin colonies, circular, flat, filamentous margin; white mycelia; soluble pigment absent; reverse white (Fig. 6 D View Figure 6 ). On DG 18, wrinkled texture, velvety, circular, flat, entire margin; white mycelia; soluble pigment absent; reverse white to pale yellow (Fig. 6 E View Figure 6 ). Colonies on MEA and MEAbl smooth texture, circular, flat, entire margin; pale yellow at the centre, white at the margin; soluble pigment absent; reverse pale brown to white (Fig. 6 F, G View Figure 6 ). On OA, smooth textured, velvety, circular, flat, entire margin; white mycelia; soluble pigment absent; reverse light yellow to white (Fig. 6 H View Figure 6 ). Colonies on PDA circular, flat, smooth texture, entire margin; white mycelia; soluble pigment absent; reverse white to light yellow (Fig. 6 I View Figure 6 ). Colonies on YES circular, flat, wrinkled texture, velvety, entire margin; white mycelia; soluble pigment absent; reverse brownish-yellow (Fig. 6 J View Figure 6 ). Sporulation abundantly produces on DG 18, MEA and MEAbl media. Sclerotia produces MEA, MEAbl and OA (Fig. 6 P View Figure 6 ).

Micromorphology.

Conidiophores monoverticillate, sometimes divaricate. Stipes hyaline, smooth – walled, 80–270 × 2–3 µm (Fig. 6 K – N View Figure 6 ). Phialides terminal, ampulliform, hyaline, smooth – walled 6–17 × 2–3.5 µm (Fig. 6 K – N View Figure 6 ). Conidia globose to subglobose, 2–4 µm diam., smooth, hyaline (Fig. 6 K – O View Figure 6 ). Sclerotia pale brown to brown, globose to irregular, 180–260 µm diam. (Fig. 6 P View Figure 6 ). Sexual morph absent.

Additional strain examined.

Thailand • Chiang Mai Province, Mae Rim District, Mae Sa , on soil in the forest dump-sites, 27 June 2024, T. Thitla & J. Monkai; CMUVR 005-2 ; living culture, MBSZU 24-010 , dried culture permanently preserved in a metabolically inactive state, CMUVR 005-2 .

Habitat and distribution.

Soil; only known from Chiang Mai Province, Thailand.

Notes.

Penicillium section Lanata - Divaricata was established by Thom (1930) to include species with biverticillate conidiophores, which usually contain a main conidiophore axis and metulae that diverge (referred to as divaricate conidiophores), as well as broadly spreading colonies ( Houbraken and Samson 2011; Pangging et al. 2021). Species within this section have been isolated from various sources, including soil, air, fluvial sediments and plants ( Nóbrega et al. 2024). Currently, the section is divided into five series: Dalearum, Janthinella, Oxalica, Rolfsiorum and Simplicissima ( Ansari et al. 2023; Visagie et al. 2024 a).

Penicillium chiangmaiense is classified within section Lanata - Divaricata , series Janthinella . In the phylogenetic tree (Fig. 3 View Figure 3 ), the new species is closely related to P. brefeldianum , P. limosum and P. michoacanense . However, P. brefeldianum produces sexual structures on cornmeal agar and P. limosum produces on CZ, MEA and OA, while P. chiangmaiense does not exhibit any sexual features ( Dodge 1933; Ueda 1995). Furthermore, the growth rate of P. limosum on MEA (42 mm in 14 days) was slower than that of P. chiangmaiense (47–51 mm in 7 days) ( Ueda 1995). In the case of P. michoacanense , the stipes (15–60 × 1–1.5 µm) and phialides (4–5 × 1.5 µm) were shorter than those of P. chiangmaiense (stipes 80–270 × 2–3 µm; phialides 6–17 × 2–3.5 µm) ( Rodríguez-Andrade et al. 2021). Moreover, P. michoacanense produced weak acid on CREA, while P. chiangmaiense does not produce it ( Rodríguez-Andrade et al. 2021). Additionally, the pairwise nucleotide comparison of P. chiangmaiense with related species revealed significant differences. The comparison of P. chiangmaiense to P. brefeldianum showed 0.90 % (5 / 556 bp) difference in ITS, 4.73 % (21 / 444 bp) in TUB, 4.28 % (24 / 561 bp) in CAM and 1.46 % (11 / 755 bp) in RPB 2, including gaps. Differences in P. chiangmaiense and P. limosum were 1.09 % (6 / 548 bp) in ITS, 5.00 % (22 / 440 bp) in TUB, 6.28 % (35 / 557 bp) in CAM and 0.93 % (7 / 755 bp) in RPB 2, including gaps. In comparison between P. chiangmaiense and P. michoacanense , the differences were 0.73 % (4 / 548 bp) in ITS, 2.84 % (11 / 388 bp) in TUB, 8.35 % (34 / 407 bp) in CAM and 1.61 % (12 / 745 bp) in RPB 2, including gaps.