Aureobasidium savitreeae Senwanna, Kodchasee, J. Kumla & N. Suwannar. 2026, sp. nov.

Information from the abstract

Aureobasidium savitreeae Senwanna, Kodchasee, J. Kumla & N. Suwannar. sp. nov. Fig. 23 Etymology. Named in honor of Thai mycologist Savitree Limtong for her contributions to Thai Mycology. Type. THAILAND • Chiang Mai Province, Mueang District, Chang Phueak, isolated from confederate vine flower (Antigonon leptopus; Polygonaceae, Caryophyllales), Jul 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, holotype = CMUB 40132 (preserved in metabolically inactive state), living culture (ex-type) = SDBR-CMU 824 = GMBCC 2498 = TBRC 21791. Cultural characteristics. After 14 days of incubation at 25 ° C in the dark, colonies on PDA reaching 45–55 mm diam., surface flat, spreading with filiform, entire margin, velvety, pale yellow (2 A 3); on MEA reaching 47–56 mm diam., surface flat, spreading with filiform, entire margin, orange white (5 A 2); on OA 65–70 mm diam., surface flat, spreading with entire margin, fluffy, pale yellow (2 A 3), with light brownish gray (4 E 2) at the margin. Description. Anamorph in vitro dematiaceous hyphomycetes. Vegetative hyphae 2.3–5.5 (– 6.8) μm wide, hyaline to dark brown, branched, septate, smooth, thin-walled, getting dark melanized and thicker, constricted at the septa with age. Conidiogenous cells (6.3 –) 8.0–17.5 (– 20) × (3.3 –) 4.0–5.5 (– 6.4) μm (x ̄ = 12.5 × 4.6 μm, n = 25), undifferentiated, intercalary, terminal, producing conidia percurrently from indistinct, short lateral denticles, giving rise to conidia that aggregate in a mucoid mass, or differentiated on hyphae, occasionally elongated, solitary, hyaline to dark brown. Conidia (3.5 –) 5.2–6.8 (– 9.1) × (2.2 –) 3.0–4.5 (– 6.5) μm (x ̄ = 6.0 × 3.7 μm, n = 200), fusoid, obovoid to ellipsoidal, hyaline to light brown, becoming brown melanized with age, aseptate, occasionally with an indistinct truncated base and a hilum, guttulate, smooth-walled. Chlamydospores (4.4 –) 5.4–9.0 (– 11.8) × 2.6–7.6 μm (x ̄ = 7.2 × 5.5 μm, n = 100), frequent produced in aerial hyphae, mostly intercalary, solitary or in branched chains, ellipsoidal, globose to subglobose, pigmented, light to dark brown, smooth-, thick-walled, septate, constricted near the septa. Endoconidia (3.8 –) 4.9–7.2 (– 8.0) × (2.2 –) 3.0–4.8 (– 5.5) μm (x ̄ = 6.1 × 3.9 μm, n = 50), obovoid to ellipsoidal, hyaline, occasionally seen in intercalary hyphal cells. Fermentation of glucose is negative. D - glucose, galactose (weak), sorbose (weak), N - acetyl glucosamine (weak), ribose (weak), xylose, L - arabinose, D - arabinose (weak), L - rhamnose, sucrose, maltose (weak), α - α - trehalose, methyl- α - D - glucoside, cellobiose, salicin (weak), melibiose (weak), lactose (weak), raffinose, melizitose, glycerol (weak), erythritol (weak), ribitol (weak), glucitol, mannitol (weak), galactitol, myo - inositol (weak), D - glucono- 1, 5 - lactone (weak), D - gluconate (weak), D - glucuronate (weak), D - galacturonic acid (weak), DL - lactate, succinate, citrate, ethanol (weak), and xylitol (weak) are assimilated, but inulin, soluble starch, and methanol are not assimilated. Ammonium sulfate, ethylamine hydrochloride, L - lysine, cadaverine, and creatine are assimilated as sole nitrogen sources. Potassium nitrate and sodium nitrite are not assimilated. After 3 weeks, light pink pigmentation and brown sediment were observed in D - glucose, D - xylose, L - arabinose, sucrose, raffinose, melizitose, and erythritol. Brown sediment formed in D - galactose, L - sorbose, N - acetyl glucosamine, D - ribose, D - arabinose, L - rhamnose, maltose, α - α - trehalose, methyl- α - D - glucoside, cellobiose, salicin, melibiose, lactose, glycerol, ribitol, D - glucitol, D - mannitol, galactitol, myo - inositol, D - glucono- 1, 5 - lactone, D - gluconate, D - glucuronate, D - galacturonic acid, DL - lactate, succinate, citrate, ethanol, and xylitol. 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. Additional strains examined. THAILAND • Phayao Province, Mueang District, isolated from oleander flower (Nerium oleander; Apocynaceae, Gentianales), Aug 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, living culture = SDBR-CMU 841. Habitat and distribution. Flowers of Antigonon leptopus and Nerium oleander. Known only from northern Thailand. Notes. The multilocus phylogenetic tree (Fig. 2) indicated that A. savitreeae formed a monophyletic clade (100 % MLBS and 0.96 BIPP support) and was sister to A. saisamorniae. However, differences in molecular data, growth temperature, and morphological and physiological characteristics, as mentioned above, together with the PHI test results (Fig. 3), supported the recognition of A. savitreeae and A. saisamorniae as distinct species. Therefore, A. savitreeae is introduced here as a new species.

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Related topics: Plant Pathogens and Fungal Diseases · Mycorrhizal Fungi and Plant Interactions · Slime Mold and Myxomycetes Research