IDENTIFICATION OF ERGOSTEROL IN VESICULAR-ARBUSCULAR MYCORRHIZAE

Ergosta-5,7,22-tri-3-enol (ergosterol) was identified by gas chromatography-mass spectrometry in roots of berseem (Trifolium alexandrinum L., cv. Landsorte) and sweet corn (Zea mays L., cv. Honeycomb-F1) infected with the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus intraradices. The fungal-derived compound ergosterol was determined quantitatively in root extracts using reverse-phase high performance liquid chromatography. The concentrations of ergosterol in VAM-infected roots reached 72-mu-g g-1 dry material in berseem and 52-mu-g g-1 in sweet corn after 80 days of growth, whereas concentrations in non-infected roots remained below 8-mu-g g-1 dry weight. Additionally, phytosterols such as beta-sitosterol, campesterol, and stigmasterol were detected in both infected and non-infected roots. Ergosterol, as a characteristic fungal substance, is proposed as an indicator of fungal biomass in the early stages of VAM infection.