Metabolomic and Biochemical analysis of Pb accumulation and tolerance in Hirschfeldia incana ; Étude métabolomique et biochimique de la tolérance et l'accumulation du Pb chez Hirschfeldia incana

International audience ; Phytoremediation is an ecological method based on the use of tolerant and (hyper)accumulator plants to rehabilitate sites polluted by heavy metals. For a better use of these plants, a deep understanding of the mechanisms that control metal tolerance and accumulation is needed. The Brassicaceae Hirschfeldia incana grows naturally in contaminated sites. Under these conditions, it exhibits significant biomass and a high capacity for lead tolerance and accumulation (1; 2). To optimize its use in Pb phytoremediation processes, we analyzed the variation of metabolomic profile by GC-MS in H.incana plants treated with Pb for 3 and 15 days. The metabolomic analysis of the organic fraction of H.incana’s aerial part showed an increase in the concentration of organic acids since the first days of treatment and a decrease in the concentration of membrane lipids and steroids, thus revealing signs of toxicity in form of lipid peroxidation. On the other hand, after 15 days of treatment, an increase in the total concentration of lipids and steroids was reported, indicating a sort of adaptation of H.incana to Pb stress. A comparison of enzyme activities and MDA content between Pb-treated and untreated plants showed a decrease in peroxidase activity and a slight increase in catalase activity after 15 days of treatment. MDA content decreased after 3 days of treatment and then increased after 15 days of treatment. Our results suggest that the plant compensates lipid peroxidation by activating other lipid biosynthetic pathways which explain the augmentation of lipid amount in 15 days treated plants. ; La phytoremédiation est une méthode écologique basée sur l’utilisation des plantes tolérantes et (hyper)accumulatrices pour la réhabilitation des sites miniers pollués par les métaux lourds. Pour une meilleure utilisation de ces plantes, une connaissance approfondie des mécanismes qui contrôlent la tolérance et l’accumulation des métaux demeure nécessaire. La Brassicacée Hirschfeldia incana pousse naturellement ...