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

Information from the abstract

Aureobasidium oroxyli Senwanna, Kodchasee, J. Kumla & N. Suwannar. sp. nov. Fig. 18 Etymology. Refers to the host genus Oroxylum, from which this species was isolated. Type. THAILAND • Chiang Mai Province, Phrao District, Nam Phrae, isolated from Indian trumpet flower (Oroxylum indicum; Bignoniaceae, Lamiales), Jul 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, holotype = CMUB 40133 (preserved in metabolically inactive state), living culture (ex-type) = SDBR-CMU 827 = GMBCC 2499 = TBRC 21786. Cultural characteristics. After 14 days of incubation at 25 ° C in the dark, colonies on PDA reaching 18–21 mm diam., surface round with raised, wrinkled margin, dry, reddish gray (10 B 2), with light gray (10 C 1) at the margin; on MEA reaching 20–25 mm diam., surface filamentous, slimy, round with raised, wrinkled, dry margin, grayish yellow (4 B 6) at center, with light gray (4 C 1) to yellowish gray (4 B 2) at the margin; on OA 25–30 mm diam., surface flat, spreading with irregular margin, wrinkled, yellowish white (2 A 2) at center, gradient from violet gray (17 D 2) to violet white (17 A 2), surrounded by light gray (17 B 1) clear zones on an agar medium. Description. Anamorph in vitro dematiaceous hyphomycetes. Vegetative hyphae (2.0 –) 3.2–6.5 (– 8.0) μm wide, hyaline to brown, branched, septate, smooth, thin-walled, getting darker and thicker with age, constricted at the septa, anastomosis observed. Conidiogenous cells 9.0–18.0 (– 22.4) × 2.9–5.2 (– 6.4) μm (x ̄ = 13.8 × 4.2 μm, n = 25), undifferentiated, intercalary, rarely terminal, producing conidia percurrently from short lateral denticles, giving rise to conidia that aggregate in a mucoid mass, or differentiated on hyphae, hyaline to brown. Conidia (4.0 –) 5.2–8.7 (– 11.3) × (2.0 –) 2.6–5.0 (– 7.0) μm (x ̄ = 6.8 × 3.6 μm, n = 200), obovoid to ellipsoidal, subglobose, hyaline, aseptate, occasionally with an indistinct truncated base and a hilum, smooth-walled, guttulate, budding occasionally observed. Chlamydospores 6.9–14.0 (– 17.5) μm (x ̄ = 10.6 μm, n = 25) µm wide, produced in aerial hyphae, mostly intercalary, solitary or in branched chains, subglobose to ellipsoidal, pigmented, light to dark brown, smooth-, thick-walled, septate, constricted near the septa. Endoconidia absent. Fermentation of glucose is negative. D - glucose, galactose, sorbose, ribose, xylose, L - arabinose, D - arabinose, L - rhamnose, sucrose, maltose, α - α - trehalose, methyl- α - D - glucoside (weak), cellobiose, salicin, melibiose (weak), lactose, raffinose, melizitose, glycerol, erythritol, ribitol (weak), glucitol (weak), mannitol, myo - inositol, D - glucono- 1, 5 - lactone, D - gluconate, D - glucuronate, D - galacturonic acid (weak), succinate, citrate, ethanol, and xylitol are assimilated, but N - acetyl glucosamine, inulin, soluble starch, galactitol, DL - lactate, 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 was observed in D - glucose. Brown sediment formed in D - xylose, L - arabinose, melibiose, and raffinose, while light brown sediment produced in cellobiose. Dark brown sediment presents in D - mannitol and D - gluconate, whereas dark sediment observed in D - ribose. 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 • Chiang Mai Province, Mueang District, Chang Phueak, isolated from Indian trumpet flower (Oroxylum indicum; Bignoniaceae, Lamiales), Jul 2024, P. Kodchasee, C. Senwanna, J. Kumla and N. Suwannarach, living culture = SDBR-CMU 822. Habitat and distribution. Flowers of Oroxylum indicum. Known only from northern Thailand. Notes. Multilocus phylogenetic analyses revealed that A. oroxyli strains SDBR-CMU 822 and SDBR-CMU 827 (ex-type) formed a distinct monophyletic lineage with 100 % MLBS and 1.00 BIPP support and were sister to A. tremulum (Fig. 2). The ITS and LSU sequence data of A. oroxyli showed similarities of 96.92 % and 98.80 %, respectively, to those of A. tremulum UN 1 (ex-type). However, the rpb 2, tef 1, and tub sequences could not be compared because sequences from the ex-type strain of A. tremulum were unavailable. Comparisons of ITS, LSU, rpb 2, tef 1, and tub sequences showed that A. oroxyli shared 99.56 %, 96.99–97.32 %, 91.39 %, 79.86–80.65 %, and 90.57 % similarity, respectively, with six A. tremulum strains obtained in this study. Because of the limited information available for A. tremulum, which was originally described only from yeast cells, detailed morphological comparisons could not be made (Crous et al. 2019). Furthermore, A. oroxyli and the A. tremulum strains obtained in this study can be morphologically distinguished by their colony coloration on MEA, with A. oroxyli forming grayish-yellow colonies with light-gray to yellowish-gray margins, whereas A. tremulum formed brownish-gray colonies with purplish-gray margins. Growth at 37 ° C was observed in A. oroxyli, whereas A. tremulum did not grow at this temperature (Crous et al. 2019; this study). Moreover, the conidia of A. oroxyli (4.0–11.3 µm) are generally shorter than those of A. tremulum (4.6–17.3 µm). Aureobasidium oroxyli can be distinguished from A. tremulum by its ability to assimilate lactose and glycerol and to produce pigmentation when grown on D - glucose (Crous et al. 2019). Thus, A. oroxyli is introduced as a novel species based on morphological and phylogenetic evidence.

Why this record is monitored

This record has an Impact Signal of 85/100 based on recency, source, collaboration, and bibliographic signals. It prioritizes monitoring and is not a judgment of research quality.

Related topics: Plant Pathogens and Fungal Diseases · Mycorrhizal Fungi and Plant Interactions · Fungal Biology and Applications