Aureobasidium castaneae C. M. Tian & N. Jiang, Journal of Fungi 7 (1, no. 64): 11 (2021)

Fig. 8

Cultural characteristics.

After 14 days of incubation at 25 ° C in the dark, colonies on PDA reaching 34–45 mm diam., surface flat, spreading, round with radiating, irregular margin, velvety, slimy, pale yellow (2 A 3), becoming olive brown (4 E 5) at the margin; on MEA reaching 28–35 mm diam., surface flat, spreading, round with radiating, irregular margin, velvety, slimy, dark brown (6 F 8) at center, becoming olive brown (4 E 5) to smoke brown (4 E 2) and white at the margin; on OA 32–45 mm diam., surface flat, spreading with irregular margin, velvety, slimy, pale yellow (2 A 3), becoming brownish gray (4 E 2), yellowish brown (5 E 8) at the margin.

Description.

Anamorph in vitro dematiaceous hyphomycetes. Vegetative hyphae 2.0–5.0 (– 6.6) μm wide, mostly hyaline, branched, septate, smooth, thin-walled, becoming light brown to brown, guttulate, thick-walled. Conidiogenous cells (4.8 –) 6.0–14.0 (– 16.0) × 2.5–6.0 (– 6.7) μm (x ̄ = 9.7 × 4.6 μm, n = 25), undifferentiated from hyphae, intercalary, rarely terminal, producing conidia percurrently from indistinct lateral denticles, giving rise to conidia that aggregate in a mucoid mass, or differentiated from hyphae, occasionally elongated, solitary, erect to lightly curved, hyaline becoming lightly melanized with age. Conidia (4.3 –) 5.0–9.0 (– 11.0) × (2.5 –) 3.0–4.5 (– 5.6) μm (x ̄ = 7 × 3.7 μm, n = 150), obovoid to ellipsoid, globose to subglobose, hyaline, becoming light brown to brown with age, aseptate, occasionally with an indistinct truncated base and a hilum, guttulate, smooth-walled, budding occasionally observed. Endoconidia (2.9 –) 3.4–5.6 × 1.6–2.5 μm (x ̄ = 4.0 × 1.9 μm, n = 25), obovoid to ellipsoid, hyaline, occasionally seen in intercalary hyphal cells.

Cardinal temperatures for growth.

Minimum 10 ° C, optimum in the range of 25 ° C to 30 ° C. No growth at 4 ° C and 37 ° C.

Strains examined.

THAILAND • Chiang Mai, Mueang District, Suthep, isolated from American cassia flower (Senna spectabilis; Fabaceae, Fabales), Aug 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, living culture = SDBR-CMU 835.

Habitat and distribution.

Leaf spots of Castanea henryi in China (Jiang et al. 2021); flowers of Senna spectabilis in Thailand (this study).

Notes.

Phylogenetic analysis showed that strain SDBR-CMU 835 clustered with A. castaneae CFCC 54591 (ex-type) in the same clade, with strong statistical support (100 % MLBS and 0.97 BIPP) (Fig. 2). The LSU and ITS sequences of strain SDBR-CMU 835 showed 100 % similarity to those of A. castaneae CFCC 54591. The morphology of strain SDBR-CMU 835 is consistent with the description provided by Jiang et al. (2021). Therefore, this strain was identified as A. castaneae. In addition, an updated description of the melanized structures of the species is provided. Prior to this study, A. castaneae was reported on Castanea henryi in China (Jiang et al. 2021). This study represents the first report of A. castaneae in Thailand.