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

Information from the abstract

Aureobasidium lannaense Senwanna, Kodchasee, J. Kumla & N. Suwannar. sp. nov. Fig. 15 Etymology. Refers to the Kingdom of Lanna, the historic name of northern Thailand, where the flowers containing the new fungus were collected. Type. THAILAND • Chiang Mai Province, Mueang District, Suthep, isolated from flosreginae flower (Lagerstroemia speciosa; Lythraceae, Myrtales), Aug 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, holotype = CMUB 40135 (preserved in metabolically inactive state), living culture (ex-type) = SDBR-CMU 863 = GMBCC 2511 = TBRC 21785. Cultural characteristics. After 14 days of incubation at 25 ° C in the dark, colonies on PDA reaching 25–28 mm diam., surface flat, spreading with filiform, irregular margin, velvety, fluffy, slimy, yellowish white (2 A 2); on MEA reaching 45–54 mm diam., surface flat, spreading, round with radiating margin, velvety, yellowish white (2 A 2), dark gray (3 F 1) to black (tabby appearance); on OA 42–47 mm diam., surface flat, spreading with irregular margin, powdery, light gray (4 D 1) and olive brown (4 E 5: tabby appearance), with light gray (4 D 1) at the margin. Description. Anamorph in vitro dematiaceous hyphomycetes. Vegetative hyphae 3.0–10.0 (– 16.0) μm wide, hyaline to dark brown, branched, septate, smooth, thin-walled, becoming light brown to golden brown, constricted at the septa, thick-walled. Conidiogenous cells (5.0 –) 7.5–15.0 (– 21.0) × (3.0 –) 4.2–7.0 (– 9.0) μm (x ̄ = 11.8 × 5.8 μm, n = 25), undifferentiated, intercalary, rarely terminal, producing conidia percurrently from indistinct, short lateral denticles, giving rise to conidia that aggregate in a mucoid mass, or differentiated on hyphae, hyaline to dark brown. Conidia oval, obovoid to ellipsoidal, elongated, or globose to subglobose, hyaline, becoming light brown with age, aseptate, occasionally with an indistinct truncated base and a hilum, guttulate, smooth-walled, (4.0 –) 5.4–9.0 (– 11.0) × 2.5–4.7 (– 6.3) μm (x ̄ = 7.0 × 3.8 μm, n = 200), budding occasionally observed. Chlamydospores (7.4 –) 8.7–11 (– 14.9) (x ̄ = 10.0 μm, n = 25) µm wide, produced in aerial hyphae, mostly intercalary, solitary or in branched chains, globose to subglobose or ellipsoidal, hyaline becoming golden brown, smooth-, thick-walled, septate, constricted near the septa. Endoconidia absent. Fermentation of glucose is negative. D - glucose, galactose, sorbose, N - acetyl glucosamine, ribose, xylose, L - arabinose, D - arabinose (weak), L - rhamnose, sucrose, maltose, α - α - trehalose, methyl- α - D - glucoside (weak), cellobiose, salicin, melibiose, lactose, raffinose, melizitose, glycerol, erythritol, ribitol, glucitol, mannitol, galactitol, myo - inositol, D - glucono- 1, 5 - lactone, D - gluconate, D - glucuronate, D - galacturonic acid, DL - lactate (weak), succinate, citrate, ethanol, 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, black sediment formed in D - glucose, D - arabinose, methyl- α - D - glucoside, and D - gluconate, while white sediment observed in lactose. 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 • Chiang Mai Province, Mueang District, Suthep, isolated from Indian head ginger flower (Cheilocostus speciosus; Costaceae, Zingiberales), Sep 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, living culture = SDBR-CMU 833. Habitat and distribution. Flowers of Cheilocostus speciosus and Lagerstroemia speciosa. Known only from northern Thailand. Notes. In the multilocus phylogenetic tree, A. lannaense SDBR-CMU 833 and SDBR-CMU 863 (ex-type) formed a distinct monophyletic lineage (100 % MLBS and 0.99 BIPP) that was sister to A. albui and A. floricola (Fig. 2). Comparisons of nucleotide sequences showed that the rpb 2 sequence of A. lannaense showed 96.97 % similarity to that of A. albui NRRL 61482 (ex-type) (18 / 594 bp, including gaps) and 96.59 % similarity to that of A. albui SDBR-CMU 866 (32 / 921 bp, including gaps), whereas the tef 1 sequence showed 93.93 % similarity to that of A. albui SDBR-CMU 866 (17 / 266 bp, including gaps). The tef 1 sequence of A. lannaense showed 93.51 % similarity to that of A. floricola SDBR-CMU 829 (ex-type) (18 / 266 bp, including gaps). Morphological comparison revealed distinct colony characteristics among the three species. On MEA, A. lannaense produced yellowish-white to dark-gray to black colonies, A. floricola produced olive-brown to black colonies with yellowish-white margins, and A. albui produced yellowish-brown to smoke-brown colonies with white margins. On OA, A. lannaense formed light-gray to olive-brown colonies with light-gray margins, differing from A. floricola, which formed yellowish-white to orange-white colonies, and A. albui, which formed whitish-gray colonies with light-gray margins. Aureobasidium lannaense can be distinguished from A. albui and A. floricola by its lack of endoconidium production. Growth at 4 ° C was observed only in A. albui, whereas both A. lannaense and A. floricola did not grow at this temperature. Moreover, the PHI test further supported the genetic distinctiveness of A. lannaense, A. albui, and A. floricola, confirming that they represent distinct species (Fig. 4). Aureobasidium lannaense can be distinguished from A. floricola by its ability to assimilate methyl- α - D - glucoside (Table 1). In addition, A. lannaense differs from A. albui in its ability to assimilate D - arabinose, L - rhamnose, salicin, glycerol, erythritol, ribitol, myo - inositol, ethanol, and xylitol as carbon sources, as well as creatine as a nitrogen source (Jumbam et al. 2025). Therefore, A. lannaense is described herein 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