Quantitative determination of indole-3-acetic acid in yeasts using high performance liquid chromatography—tandem mass spectrometry

High performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was applied to the comprehensive analysis of the ability of yeast strains to synthesize a plant hormone indole-3-acetic acid (IAA). A total of 124 strains (37 species) of yeasts isolated from various regions and substrates were studied. Testing of IAA production showed that 92% strains were capable of IAA synthesis. The results indicated that, in general, ascomycetous yeasts were more active auxin producers than basidiomycetous ones. Geographically, strains from tropical regions were the most active IAA producers. Analysis of the substrate variability of the strains showed higher auxin production (on average) by the yeasts isolated from plants compared to the soil isolates, indicating a specific regulatory role of the plant yeast population.