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

Information from the abstract

Aureobasidium phayaoense Senwanna, Kodchasee, J. Kumla & N. Suwannar. sp. nov. Fig. 19 Etymology. Refers to Phayao Province, where the flowers containing the new fungus were collected. Type. THAILAND • Phayao Province, Mueang District, isolated from Egyptian star cluster flower (Pentas lanceolata; Rubiaceae, Gentianales), Aug 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, holotype = CMUB 40126 (preserved in metabolically inactive state), living culture (ex-type) = SDBR-CMU 852 = GMBCC 2508 = TBRC 21787. Cultural characteristics. After 14 days of incubation at 25 ° C in the dark, colonies on PDA reaching 39–45 mm diam., surface flat, spreading with entire margin, velvety, concentric, gradient from gray (4 B 1), brownish gray (4 E 2) to grayish brown (7 E 3), with yellowish white (2 A 2) at the margin; on MEA reaching 40–48 mm diam., surface flat, spreading with entire margin, wrinkled, velvety, concentric, gradient from dull yellow (3 B 3) to grayish yellow (4 B 6), with yellowish white (2 A 2) at the margin; on OA 55–65 mm diam., surface flat, spreading with entire margin, wrinkled, brownish orange (6 C 8), grayish brown (6 E 3) with light gray (6 B 1) to brownish gray (4 E 2) at the margin. Description. Anamorph in vitro dematiaceous hyphomycetes. Vegetative hyphae (2.0 –) 3.0–9.0 (– 12.0) μm wide, hyaline, light to brown with age, branched, septate, smooth, thin-walled, becoming dark melanized, getting darker and thicker with age, constricted at the septa, minute echinulate. Conidiogenous cells (7.5 –) 8.7–13.8 (– 17.4) × (3.6 –) 4.5–6.5 (– 7.5) μm (x ̄ = 10.9 × 5.5 μm, n = 25) µm, 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, light to dark brown. Conidia (4.0 –) 5.5–9.6 (– 11.8) × (1.9 –) 2.8–6.0 (– 7.4) μm (x ̄ = 7.6 × 4.3 μm, n = 170), oval, obovoid to ellipsoidal or elongated, or 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. Chlamydospores (9.0 –) 10.4–14.0 (– 17.5) µm wide (x ̄ = 12.6 μm, n = 30), frequent produced in aerial hyphae, mostly intercalary, solitary, subglobose to ellipsoidal, pigmented, light to dark brown, septate, smooth-, thick-walled. Endoconidia absent. Fermentation of glucose is negative. D - glucose, galactose, sorbose, N - acetyl glucosamine (weak), ribose, xylose, L - arabinose, D - arabinose, L - rhamnose, sucrose, maltose, α-α- trehalose, methyl- α - D - glucoside, cellobiose, salicin, melibiose (weak), lactose, raffinose, melizitose, glycerol, erythritol, ribitol, glucitol, mannitol, galactitol, myo - inositol, D - glucono- 1, 5 - lactone, D - gluconate, D - glucuronate, D - galacturonic acid (weak), citrate, ethanol, and xylitol are assimilated, but inulin, soluble starch, DL - lactate, succinate, 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, dark brown sediment formed in N - acetyl glucosamine, D - xylose, L - arabinose, D - arabinose, L - rhamnose, sucrose, maltose, methyl- α - D - glucoside, cellobiose, salicin, melibiose, lactose, raffinose, melizitose, glycerol, erythritol, ribitol, D-glucitol, galactitol, D - glucono- 1, 5 - lactone, D - gluconate, D - glucuronate, D - galacturonic acid, and citrate, while light brown sediment formed in α - α - trehalose. Black sediment formed in D - glucose, D - galactose, L - sorbose, D - ribose, D - mannitol, myo - inositol, and xylitol, while white sediment observed in ethanol. Cardinal temperatures for growth. Minimum 10 ° C, optimum in the range of 25 ° C to 30 ° C, maximum 37 ° C. No growth at 4 ° C. Additional strains examined. THAILAND • Phayao Province, Mueang District, isolated from bush clock vine flower (Thunbergia erecta; Acanthaceae, Lamiales), Aug 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, living culture = SDBR-CMU 811 and SDBR-CMU 857. Habitat and distribution. Flowers of Pentas lanceolata and Thunbergia erecta. Known only from northern Thailand. Notes. Phylogenetic analyses showed that A. phayaoense SDBR-CMU 852 (ex-type) and SDBR-CMU 857 formed a distinct lineage sister to A. pollinicola, with 80 % MLBS and 0.90 BIPP support (Fig. 2). Comparisons of ITS, LSU, rpb 2, tef 1, and tub nucleotide sequences showed that A. phayaoense differed from A. pollinicola by 1.01 % (6 / 592 bp, including gaps), 0.33 % (3 / 901 bp, including gaps), 4.85 % (46 / 948 bp, including gaps), 7.83 % (21 / 268 bp, including gaps), and 2.93 % (12 / 409 bp, including gaps), respectively. Although comparisons of the ITS, LSU, and tub loci indicated that A. phayaoense was not markedly different from A. pollinicola, the rpb 2 and tef 1 sequences revealed clear differences. Morphologically, the colony colors of A. phayaoense and A. pollinicola differed across culture media. On PDA, A. phayaoense produced gray to grayish-brown colonies with a yellowish-white margin, whereas A. pollinicola formed light- to dark-yellowish colonies with a yellowish-white margin. On MEA, colonies of A. phayaoense were dull yellow to grayish yellow with a yellowish-white margin, compared with the grayish-yellow colonies with a light-gray margin of A. pollinicola. On OA, A. phayaoense produced brownish-orange to grayish-brown colonies with a light-gray to brownish-gray margin, whereas A. pollinicola formed yellowish-white colonies with a light-gray margin. The micromorphological features of A. phayaoense and A. pollinicola are similar in size; however, A. phayaoense can be distinguished from A. pollinicola by the absence of endoconidium production. Moreover, PHI analyses revealed no evidence of significant recombination between A. phayaoense and A. pollinicola (Fig. 3). Aureobasidium phayaoense can be distinguished from A. pollinicola by its inability to assimilate DL - lactate and succinate (Table 1). Hence, A. phayaoense is introduced as a new species based on combined morphological and phylogenetic evidence.

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Related topics: Mycorrhizal Fungi and Plant Interactions · Plant Pathogens and Fungal Diseases · Yeasts and Rust Fungi Studies