Penicillium thailandense N. Suwannarach, S. Khuna & J. Kumla, 2023

Khuna, Surapong, Kumla, Jaturong, Thitla, Tanapol, Hongsanan, Sinang, Lumyong, Saisamorn & Suwannarach, Nakarin, 2023, Penicillium thailandense (Aspergillaceae, Eurotiales), a new species isolated from soil in northern Thailand, Phytotaxa 612 (1), pp. 33-45 : 38-40

Penicillium thailandense N. Suwannarach, S. Khuna & J. Kumla sp. nov. Figure 2

MycoBank number: MB847950.

Etymology:—‘ thailandense ’ referring to Thailand, where soil containing the new fungus was collected.

Holotype:— THAILAND, Lamphun Province, Mueang Lamphun District, Sribuaban Subdistrict , 18°32′11′′ N, 99°07′30′′ E, isolated from soil in deciduous dipterocarp forest, 10 December 2021, S. Khuna, SDBR-CMU442 , preserved in a metabolically inactive state.

Gene sequences (from holotype):—ITS ( OR186737 ), BenA ( OP603898 ), CaM ( OP603900 ), and rpb2 ( OP603902 ).

Culture characteristics:—Colonies at 25°C for one week on PDA and YES slightly raised or umbonate, colony texture fasciculate, margin undulate; mycelia white; reverse light yellow; soluble light yellow pigment. Colonies on CYA convex, colony texture fasciculate, margin undulate; mycelia grey in the centre, orangish white at the margin; reverse dark brown; exudate present as clear or pale-yellow droplets; soluble brown pigment. Colonies on CYAS sulcate, raised at centre, margin undulate; mycelia white; reverse brown; soluble light brown pigment. Colonies on CZA raised, colony texture fasciculate, margin undulate; mycelia pale orange in the centre, white at the margin; reverse brown; exudate present as clear or pale-yellow droplets; soluble yellow pigment. Colonies on DG 18 flat, raised at centre, margin entire; mycelia white; reverse light yellow; soluble pigment absent. Colonies on MEA raised, colony margin undulate; mycelia white; reverse light yellow; soluble light yellow pigment. Colonies on OA flat, margin entire; mycelia light gray in the centre, white at the margin; reverse yellow; exudate present as large clear or pale-yellow droplets; soluble dull green pigment. On CREA thin colonies, acid production absent. Sporulation abundantly produced on CYA and CYAS. While, PDA, CZA, DG18, MEA, OA, YES, and CREA exhibited poor sporulation. Sclerotia present on CYA, CZA, and OA, white to dark gray, globose to irregular, 35–450 µm in diam. Conidiophores monoverticillate, sometimes biverticillate. Stipes smooth-walled, 13–120 × 1–4 µm. Phialides borning solitary from the branch, in verticils of 3 to 9, ampulliform, 5–10 × 2–4 µm. Conidia globose to subglobose, 3–4 µm diam., smooth, light brown in all of the agar media.

Geographical distribution:—Known only from northern Thailand. According to GlobalFungi, the identical ITS sequences (similarity ≥ 98%) were found in soil samples from the forest in southwestern China ( Sun et al. 2021) and in shoot of seagrass [ Enhalus acoroides (Linnaeus f.) Royle ] in Malaysia ( Wainwright et al. 2019). The sites have a tropical climate (MAT avg. 21.6°C, MAP avg. 1418 mm).

Additional specimen examined:— THAILAND, Lamphun Province, Mueang Lamphun District, Sribuaban Subdistrict , 18°32′11′′ N, 99°07′30′′ E, isolated from soil in deciduous dipterocarp forest, 10 December 2021, S. Khuna, SDBR-CMU443 . Gene sequences ITS ( OR186738 ), BenA ( OP6038998 ), CaM ( OP603901 ), and rpb2 ( OP603903 ) .

Note:—The colony characteristics of P. thailandense on CYAS and DG18 at 25°C for one week were similar to P. sanjayi . However, P. thailandense can be distinguished from P. sanjayi by its white to dark gray sclerotia, whereas P. sanjayi has cream sclerotia ( Table 3 ) ( Ashtekar et al. 2022).

In addition, the growth of P. thailandense at 25°C on CYA, CYAS, MEA and YES was slower than P. sanjayi (25–27, 30–39, 16–20 and 29–31 mm, respectively), but was displayed faster growth than P. sanjayi on CZA and OA (14–16 and 14–15 mm, respectively) ( Ashtekar et al. 2022). While, P. thailandense on CYA at 30°C showed faster growth than P. sanjayi (10–12 mm) ( Ashtekar et al. 2022). Remarkedly, P. sanjayi did not grow on CYA and MEA at 37°C, but P. thailandense did on both media. Based on the micromorphological characteristics, P. thailandense has both monoverticillate and biverticillate conidiophores, in contrast to P. sanjayi which is strictly monoverticillate. Moreover, P. sanjayi differs from P. thailandense by its smaller (2–2.5 µm) and roughened to verruculose conidia ( Table 3 ) ( Ashtekar et al. 2022). The multi-gene phylogenetic analysis indicated that isolates of P. thailandense formed a distinct clade within Penicillium section Citrina , and as a sister clade to P. sanjayi . Moreover, a pairwise nucleotide comparison of BenA , CaM, and rpb2 data also indicated that P. thailandense differs from P. sanjayi by having 1.56, 1.64, and 1.52% bp differences (7/448, 9/550, and 15/987 bp), respectively.

Figures

FIGURE 2. Penicillium thailandense (SDBR-CMU442, holotype). Colonies incubated at 25°C for one week. a. PDA; b. CYA; c. CYAS; d. CZA; e. DG18; f. MEA; g. OA; h. YES; i. CREA; j–m. Conidiophores; n. Conidia. Scale bars: a–i = 10 mm, j–n = 5 µm.