Increment of abiotic stress tolerance by metabolic engineering of compatible solutes

ABSTRACT: Abiotic stresses, especially salinity and drought, are the primary causes of crop loss worldwide. Plant adaptation to environmental stresses is dependent upon the activation of cascades of molecular networks involved in the expression of specific stress related genes and metabolites. Molecular and genomic analyses have facilitated gene discovery and enabled genetic engineering, which involved in metabolite biosynthesis pathways, using several functional or regulatory genes to activate specific or broad pathways related to drought tolerance in plants. On a whole, Plant engineering strategies for abiotic stress tolerance rely on the expression of genes that are involved in signaling and regulatory pathways or genes that encode proteins conferring stress tolerance or enzymes present in pathways leading to the synthesis of functional and structural metabolites. Accumulations of compatible solutions such as betain, proline and alcohol sugars are current responses and strategies that may protect plants against environmental changes. However some plants have been genetically engineered to express enzymes that catalyze the synthesis of various compatible solutes. But our limited knowledge of stress-associated metabolism remains a major gap in our understanding. In fact it is not yet fully understood how these compounds are involved in the stress tolerance of whole plants. Overall metabolic profiling of plants under stress is an important tool to study stress-induced changes in metabolites.