Deciphering salinity resistance in Amaranthus cruentus in relation to its nutritional value: a bright future for an old plant

Some amaranths (Amaranthus spp.) are valuable crops used either for leaf production (mainly in Africa) or seed production. Amaranthus cruentus, domesticated by Aztec civilization in Central America, is used for both purposes. It produces highly nutritive seeds with about 15% proteins whose amino acid profile is particularly suitable for human diet, 50-60% starch, dietary fibers and insaturated fatty acids. Its leaves are rich in several essential minerals (e.g. Fe, Zn), vitamins and proteins. This species has been shown to be tolerant to several abiotic stresses, including drought, heat and salinity. Soil salinity, mainly caused by NaCl accumulation, is today a widespread problem that affects more than 800 million hectares (mainly in arid- and semi-arid areas) and is expected to worsen in the future decades. It is however urgent to keep these areas productive despite salinity because of the strong expected increase in food demand. Major staple crops (rice, wheat, soybean) breeding has been performed for a long time without consideration for this recent problem. Therefore, there is few genetic variability for salt-tolerance among these species. That is why. some salt-tolerant and under-domesticated crops like amaranths gain more and more attention from agronomists and plant scientists as crop candidates that could be grown on salt-contaminated areas. In this context, it is necessary to better understand how A. cruentus copes with soil salinity. My PhD thesis projects is divided into two main objectives: (1) deciphering the mechanisms underlying salt tolerance across several ‘leaf’ and ‘grain’ A. cruentus varieties, with physiological, proteomic and metabolomic approaches; (2) understanding how salinity modulates the nutritive qualities of seeds and leaves, including health-promoting metabolites. The project will include experiments in controlled environments (greenhouses at SeFy, UCLouvain) and field work on salt-contaminated areas in Benin