Impact of anthracene on the arbuscular mycorrhizal fungus lipid metabolism

Abstract

Anthracene, a low-molecular-weight polycyclic aromatic hydrocarbon (PAH) originating mainly from anthropogenic activities, represents one of the major persistent organic pollutants frequently detected in polluted soils. A few studies have reported the negative effect of PAH on the main steps of the arbuscular mycorrhizal fungi (AMF) life cycle resulting from lipid peroxidation; however, little is known regarding the impact of anthracene on extraradical AMF lipid metabolism. Radiolabelling experiments showed significant decreases of [1-14C]acetate incorporation into the sterol precursors (4,4-dimethylsterols and 4α-methylsterols) and in the total phospholipids (PL) of Rhizophagus irregularis (Blaszk., Wubet, Renker & Buscot) extraradical mycelium when grown in the presence of anthracene. These findings suggested a slowing down of the sterol and total PL biosynthesis pathways in AMF treated with anthracene. The negative impact of the organic pollutant on AMF membrane lipid biosynthesis may explain the growth inhibition of the fungus after PAH exposure. This study increases the understanding of the biochemical mechanisms involved in PAH ecotoxicity on AMF.