Aureobasidium florale Senwanna, Kodchasee, J. Kumla & N. Suwannar. 2026, sp. nov.
Authors: Senwanna, Chanokned, Kodchasee, Pratthana, Kathongthung, Chirayut, Samarakoon, Milan C., Khunnamwong, Pannida, Kumla, Jaturong, Suwannarach, Nakarin
Type: Taxonomic treatment
Published: 2026-08-03
Keywords: Biodiversity, Taxonomy, Fungi, Ascomycota, Dothideomycetes, Dothideales, Saccotheciaceae, Aureobasidium, Aureobasidium florale

<p><i>Aureobasidium florale</i> Senwanna, Kodchasee, J. Kumla & N. Suwannar. sp. nov.</p><p>Fig. 11</p><p><b>Etymology.</b></p><p>Refers to its association with flowers, the substrate from which this species was isolated.</p><p><b>Type.</b></p><p>THAILAND • Chiang Mai Province, Mueang District, Suthep, isolated from teak flower (<i>Tectona grandis</i>; <i>Lamiaceae</i>, <i>Lamiales</i>), Aug 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, <i>holotype</i> = CMUB 40136 (preserved in metabolically inactive state), living culture (ex-type) = SDBR-CMU 832 = GMBCC 2501 = TBRC 21781.</p><p><b>Cultural characteristics.</b></p><p>After 14 days of incubation at 25 ° C in the dark, colonies on PDA reaching 35–42 mm diam., surface flat, spreading with filiform, irregular margin, velvety, slimy, yellowish white (2 A 2); on MEA reaching 33–40 mm diam., surface flat, spreading with filiform, irregular margin, velvety, slimy, orange white (5 A 2); on OA 36–40 mm diam., surface flat, spreading with filiform, irregular margin, velvety, slimy, yellowish white (2 A 2) at center, light gray (3 D 1) at the margin.</p><p><b>Description.</b></p><p><i><i>Anamorph</i> in vitro</i> dematiaceous hyphomycetes. <i>Vegetative hyphae</i> (2 –) 3.8–8.6 (– 14.9) μm wide, hyaline to dark brown, getting darker and thicker with age, branched, septate, smooth. <i>Conidiogenous cells</i> (7.5 –) 8.6–10.5 (– 12.5) × (5.5 –) 6.2–7.6 μm (<i>x ̄</i> = 11.1 × 7.8 μm, <i>n</i> = 20), 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, hyaline to light brown, occasionally elongated, solitary, becoming brown to dark brown with age. <i>Conidia</i> (3.8 –) 5.7–10.4 (– 13.6) × (2.6 –) 4–5.6 (– 7) μm (<i>x ̄</i> = 7.8 × 4.8 μm, <i>n</i> = 200), obovoid to ellipsoidal, elongated, or globose to subglobose, hyaline becoming melanized with age, aseptate, occasionally with an indistinct truncated base and a hilum, guttulate, smooth-walled, budding occasionally observed. <i>Chlamydospores</i> 6.0–9.5 (– 13.6) (<i>x ̄</i> = 8.5 μm, <i>n</i> = 25) µm wide, produced in aerial hyphae, intercalary, solitary or in branched chains, subglobose, pigmented, dark brown, smooth-, thick-walled, septate, constricted near the septa. <i>Endoconidia</i> (3.7 –) 4.3–5.4 (– 6) × 2.7–3.6 (– 4.5) μm (<i>x ̄</i> = 4.8 × 3.3 μm, <i>n</i> = 25), obovoid to ellipsoidal, hyaline, occasionally seen in intercalary hyphal cells.</p><p>Fermentation of glucose is negative. <i>D</i> - glucose, galactose, sorbose (weak), <i>N</i> - acetyl glucosamine, ribose (weak), xylose, <i>L</i> - arabinose (weak), <i>D</i> - arabinose (weak), <i>L</i> - rhamnose, sucrose, maltose, <i>α</i> - <i>α</i> - trehalose (weak), methyl- <i>α</i> - <i>D</i> - glucoside (weak), cellobiose, salicin (weak), melibiose, lactose (weak), raffinose, melizitose, glycerol (weak), erythritol (weak), ribitol (weak), glucitol (weak), mannitol (weak), galactitol (weak), <i>myo</i> - inositol (weak), <i>D</i> - glucono- 1, 5 - lactone (weak), <i>D</i> - gluconate (weak), <i>D</i> - glucuronate (weak), <i>D</i> - galacturonic acid (weak), succinate (weak), citrate, ethanol (weak), and xylitol (weak) are assimilated, but inulin, soluble starch, <i>DL</i> - lactate, and methanol are not assimilated. Ammonium sulfate, ethylamine hydrochloride, <i>L</i> - lysine, cadaverine, and creatine are assimilated as sole nitrogen sources. Potassium nitrate and sodium nitrite are not assimilated. After 3 weeks, light brown sediment formed in <i>D</i> - glucose, <i>D</i> - galactose, <i>L</i> - sorbose, <i>N</i> - acetyl glucosamine, <i>D</i> - arabinose, <i>L</i> - rhamnose, sucrose, maltose, <i>α</i> - <i>α</i> - trehalose, cellobiose, salicin, melibiose, lactose, raffinose, melizitose, erythritol, ribitol, <i>D</i> - glucitol, <i>D</i> - mannitol, <i>myo</i> - Inositol, <i>D</i> - glucuronate, <i>D</i> - galacturonic acid, succinate, citrate, and ethanol. Black sediment formed in <i>D</i> - ribose, <i>D</i> - xylose, <i>L</i> - arabinose, methyl- <i>α</i> - <i>D</i> - glucoside, glycerol, galactitol, <i>D</i> - glucono- 1, 5 - lactone, <i>D</i> - gluconate, and xylitol.</p><p><b>Cardinal temperatures for growth.</b></p><p>Minimum 10 ° C, optimum in the range of 25 ° C to 30 ° C. No growth at 4 ° C and 37 ° C.</p><p><b>Additional strains examined.</b></p><p>THAILAND • Chiang Mai Province, Mueang District, Suthep, isolated from teak flower (<i>Tectona grandis</i>; <i>Lamiaceae</i>, <i>Lamiales</i>), Aug 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, living culture = SDBR-CMU 830; living culture = SDBR-CMU 831; peregrina flower (<i>Jatropha integerrima</i>; <i>Euphorbiaceae</i>, <i>Malpighiales</i>), Aug 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, living culture = SDBR-CMU 840; SDBR-CMU 850; Chang Phueak, isolated from daisy flower (<i>Thymophylla tenuiloba</i>; <i>Asteraceae</i>, <i>Asterales</i>), Jul 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, living culture = SDBR-CMU 862.</p><p><b>Habitat and distribution.</b></p><p>Flowers of <i>Jatropha integerrima</i>, <i>Tectona grandis</i>, and <i>Thymophylla tenuiloba</i>. Known only from northern Thailand.</p><p><b>Notes.</b></p><p>The multilocus phylogenetic tree showed that <i>A. florale</i> SDBR-CMU 830, SDBR-CMU 831, SDBR-CMU 832 (ex-type), SDBR-CMU 840, SDBR-CMU 850, and SDBR-CMU 862 formed a well-supported monophyletic lineage (99 % MLBS and 0.98 BIPP) that was sister to <i>A. albui</i>, <i>A. castaneae</i>, <i>A. floricola</i>, and <i>A. lannaense</i> (Fig. 2). Additionally, the PHI test results (Fig. 4) indicated significant genetic differentiation, supporting the recognition of <i>A. florale</i> as a distinct species from <i>A. albui</i>, <i>A. castaneae</i>, <i>A. floricola</i>, and <i>A. lannaense</i>. Morphologically, colonies of <i>A. florale</i> on MEA are orange white, clearly differing from the grayish-brown colonies of <i>A. albui</i>, the olive-brown colonies of <i>A. castaneae</i>, the olive-brown to black colonies with a yellowish-white margin of <i>A. floricola</i>, and the yellowish-white and dark-gray to black colonies of <i>A. lannaense</i>. Although the micromorphology of <i>A. florale</i> is similar to that of <i>A. albui</i>, <i>A. castaneae</i>, <i>A. floricola</i>, and <i>A. lannaense</i>, these taxa can be distinguished based on multilocus phylogenetic analyses. Moreover, <i>A. florale</i> differs from <i>A. lannaense</i> by the presence of endoconidia. Furthermore, <i>A. florale</i> can be distinguished from <i>A. floricola</i> and <i>A. lannaense</i> by its inability to assimilate <i>DL</i> - lactate (Table 1). It also differs from <i>A. floricola</i> in its ability to assimilate methyl-α- <i>D</i> - glucoside. In addition, <i>A. florale</i> differs from <i>A. albui</i> in its ability to assimilate <i>D</i> - arabinose, <i>L</i> - rhamnose, salicin, glycerol, erythritol, ribitol, <i>myo</i> - inositol, ethanol, xylitol, and creatine (Jumbam et al. 2025). Moreover, <i>A. florale</i> did not produce pigmentation when grown in <i>L</i> - sorbose, erythritol, <i>D</i> - mannitol, or <i>D</i> - glucono- 1, 5 - lactone, whereas <i>A. albui</i> produced pigmentation (Jumbam et al. 2025). Hence, <i>A. florale</i> is introduced as a new species based on both morphological characteristics and molecular data.</p>