The primary goal of the project is the recovery of arid and semi-arid soils in Latin America by their cultivation with plants metabolically engineered to resist biotic stresses such as drought, salinity, cold or freezing conditions. Two food crops, potato and beans, which are not natural resistant to such stresses, will be genetically manipulated by the introduction of genes responsible for the synthesis of compatible solutes. This will involve the use of already characterize deukaryotic and prokaryotic genes and the isolation and characterization of new genes for the synthesis of these osmoprotective compounds. In addition, the improvement of soil fertility will be approached by the establishment of a more efficient nitrogen fixation by bean root nodules under osmotic stress. This is intended to be achieved by the symbiotic combination of stress-resistant beans and host-specific Rhizobium strains.