Genetic analysis identifies quantitative trait loci controlling rosette mineral concentrations in Arabidopsis thaliana under drought
Résumé
Rosettes of 25 Arabidopsis thaliana accessions and an Antwerp-1 (An-1) x Landsberg erecta (Ler) population of recombinant inbred lines (RILs) grown in optimal watering conditions (OWC) and water deficit conditions (WDC) were analysed for mineral concentrations to identify genetic loci involved in adaptation of mineral homeostasis to drought stress. Correlations between mineral concentrations were determined for accessions and a quantitative trait locus (QTL) analysis was performed for the RIL population. Plant growth and rosette mineral contents strongly decreased in WDC compared with OWC. Mineral concentrations also generally decreased, except for phosphorus (P), which remained constant, and potassium (K), which increased. Large variations in mineral concentrations were observed among accessions, mostly correlated with total rosette leaf area. Mineral concentration QTLs were identified in the RIL population, but only a few were common for both conditions. Clusters of mineral concentration QTLs often cosegregated with dry weight QTLs. Water deficit has a strong effect on rosette mineral status. This is genetically determined and seems largely a pleiotropic effect of the reduction in growth. The low number of common mineral concentration QTLs, shared among different RIL populations, tissues and conditions in Arabidopsis, suggests that breeding for robust, mineral biofortified crops will be complex.