Abstract

The development of novel phytoremediation strategies to mitigate mercury contamination, an increasingly important worldwide threat, could be enhanced by identifying Hg-tolerant legume cultivars. A fast method was thus developed to screen a germplasm collection of the model legume Medicago truncatula for Hg tolerance, testing 258 accessions at the seedling stage in a miniaturized hydroponic system and using root growth as an indicator of tolerance. To validate the results of the screening, the Hg-tolerant cultivars identified were analyzed in a referenced hydroponic growth assay. The different growth parameters measured in this assay were then subjected to a factorial analysis (principal component analysis method) in order to establish indices of tolerance, which further supported the rapid method of screening. Accordingly, four Hg-tolerant M. truncatula cultivars were selected that might serve as source material for genetic improvement, as model cultivars to study Hg tolerance in legumes and/or to develop soil phytoremediation approaches.