Penicillium danzhouense C. Liu, Z. Q. Zeng & W. Y. Zhuang, 2023

Penicillium danzhouense C. Liu, Z. Q. Zeng & W. Y. Zhuang, 2023

Remark.

In: subgenus Aspergilloides, section Exilicaulis series Erubescentia .

Colony diam.

(in mm) 7 days, 25 ° C: CYA 18-19, MEA 20-23, CY 20 S 15-17, CYAS 8-10, CZ 15-16, OA 19-20, CREA 16-17 and PDA 18-19. 7 days, 30 ° C: CYA 17-20. 7 days, 37 ° C: CYA 10-12.

Culture characteristics.

On CYA at 25 ° C after 7 days, colonies were slightly raised with undulate margins; mycelium white (1 A 1), velvety in texture; sporulation very sparse, conidia en masse not determined sclerotia absent; exudate hyaline; no soluble pigments produced; reverse pale yellow (4 A 3) (Fig. 6 A View Figure 6 ). On MEA after 7 days, colonies were crateriform with undulate margins; mycelium white (1 A 1), texture velvety; sporulation moderately dense, conidia en masse greyish white (2 B 1); sclerotia absent; exudate hyaline; no soluble pigments produced; reverse champagne (4 A 4) (Fig. 6 B View Figure 6 ). On CY 20 S after 7 days, colonies were crateriform with undulate margins; mycelium white (1 A 1), velvety; sporulation very sparse, conidia en masse not determined; sclerotia absent; exudate hyaline; no soluble pigments produced; reverse champagne (4 A 4) (Fig. 6 C View Figure 6 ). On CYAS after 7 days, colonies were slightly raised with undulate margins; mycelium white (1 A 1), velvety; sporulation very sparse, conidia en masse not determined; sclerotia and exudate absent; no soluble pigments produced; reverse pale yellow (4 A 3) (Fig. 6 D View Figure 6 ). On CZ after 7 days, colonies were crateriform with undulate margins; mycelium white (1 A 1), velvety; sporulation very sparse, conidia en masse not determined; sclerotia and exudate absent; no soluble pigments produced; reverse yellowish white (4 A 2) (Fig. 6 E View Figure 6 ). On OA after 7 days, colonies were plain with undulate margins; mycelium white (1 A 1), felty; sporulation absent to very sparse, conidia en masse not determined; sclerotia and exudate absent; no soluble pigments produced; reverse white (1 A 1) (Fig. 6 F View Figure 6 ). On CREA after 7 days, colonies were slightly raised with undulate margins; mycelium white (1 A 1), velvety; sclerotia and exudate absent; no soluble pigments produced; acid production absent; base production present (Fig. 6 G View Figure 6 ). On PDA after 7 days, colonies were slightly raised with undulate margins; mycelium white (1 A 1), velvety; sporulation moderately dense, conidia en masse greyish white (2 B 1); sclerotia absent; exudate hyaline; no soluble pigments produced; reverse yellowish white (2 A 2) (Fig. 6 H View Figure 6 ). On CYA at 30 ° C after 7 days, colonies were slightly raised, radially sulcate with undulate margins; mycelium white (1 A 1), velvety; sporulation very sparse, conidia en masse not determined; sclerotia and exudate absent; no soluble pigments produced; reverse pale yellow (4 A 3) (Fig. 6 I View Figure 6 ). On CYA at 37 ° C after 7 days, colonies were umbonate with undulate margins; mycelium white (1 A 1), velvety; sporulation absent to very sparse, conidia en masse not determined; sclerotia and exudate absent; no soluble pigments produced; reverse champagne (4 A 4) (Fig. 6 J View Figure 6 ).

Micromorphology.

Conidiophores monoverticillate, unbranched, smooth-walled, hyaline, measuring 7.0–24.0 × 1.0–2.0 µm (Fig. 7 A, B View Figure 7 ). Phialides ampulliform, occurring singly or in groups of up to seven per conidiophore, smooth-walled, hyaline, measuring 5.0–10.5 × 1.5–3.0 µm (Fig. 7 C View Figure 7 ). Conidia globose measuring 2.0–3.0 µm. Under scanning electron microscopy ( SEM), conidia appear globose and distinctly rugose (Fig. 7 D View Figure 7 ). Sclerotia not observed. Sexual morph absent.

Habitat and distribution.

Tidal flat sediment in Hainan Province, China in 2020 and Mangrove sediment in Chanthaburi Province, Thailand in 2023.

Note.

Penicillium danzhouense was isolated from Thailand and represents the first record of this species in the country, and only the second report worldwide. Phylogenetic analysis based on a multilocus dataset placed our isolates within the same clade as P. danzhouense CGMCC 3.25204 , the ex-type strain (Fig. 2 View Figure 2 ), with strong statistical support. The morphological characteristics of our isolates closely correspond to the description of P. danzhouense by Liu et al. (2023), particularly in conidial size (2–3 μm), colony colours on CYA, MEA and PDA (white), reverse colony colours (light yellow), and colony diameter on PDA, all of which fall within the known range of the species. The environmental conditions of the sampling sites were also comparable, as the species was previously reported from tidal flat sediment in China and is here isolated from mangrove sediment in Thailand.

However, minor morphological deviations were observed when compared with the holotype. The conidiophores of our isolates tend to be shorter (7–24 μm vs. 12–40 μm in the holotype), whereas the phialides are slightly larger (5–10.5 μm vs. 4.6–8.7 μm). The number of phialides per conidiophore also varied slightly ( 1–7 in our isolates vs. 2–5 in the holotype). Growth characteristics on different media additionally showed subtle differences: colonies on CYA grew more slowly than the holotype ( 18–19 mm vs. 21–24 mm), whereas growth on MEA ( 20–23 mm vs. 14–17 mm) and on CYA at 37 ° C ( 10–12 mm vs. 6–7 mm) was comparatively faster. Overall, the congruence of phylogenetic evidence and morphological similarity, with only minor intraspecific variations, supports the identification of these isolates as Penicillium danzhouense .