Global metabolomics analysis reveals distinctive tolerance mechanisms in different plant organs of lentil (Lens culinaris) upon salinity stress

Background and Aims Omic technologies in the past years have provided a variety of data in model plants. In legumes, results omicron n Lotus japonicus and Medicago truncatula have highlighted the biochemistry which takes place inside cells under a variety of abiotic stresses. Here we conducted metabolomics in the forage legume lentil (Lens culinaris) upon salinity stress on acclimated and non-acclimated plants and compared results from leaf and root analyses. Methods We used two lentil varieties, originated from different geographical locations and studied differences in their global metabolite profile i) using gradual or initial application of salt stress, ii) between leaves and roots, and iii) between the varieties. Results Most important differences were noted in salinity induced diminished abundance of organic acids in both varieties' leaves and roots, accumulation of sugars and polyols in leaves, and accumulation of other key-metabolites, such as L-asparagine, D-trehalose, allantoin and urea in the roots. We also demonstrated the driver of deleterious Cl- accumulation in leaves for potential compartmentalization in the vacuole, a defensive mechanism for withstanding salinity stress in plants. Finally, a model is suggested of how legumes upregulate a metabolic pathway, which involves purines catabolism in order to assimilate carbon and nitrogen, which are limited during salinity stress. Conclusions Future omics works with lentil can help understanding the regulation of the biochemical "arsenal" against abiotic stresses such as salinity and render the selection of better crops.