Metabolomics and Molecular Physiology Perspective for Drought and Salinity Stress Tolerance

Among abiotic stresses, drought and salinity are mainly affecting crop production. Reactive oxygen species are produced during most of abiotic stresses and can damage cellular components. Therefore, plants produce specific antioxidants (e.g. carotenoids, xanthophylls), metabolites (e.g. flavonoids, phenols), osmoregulatory solutes (e.g. proline, sucrose) and thylakoid stabilizing isoprenes. Plant metabolic networks are complex, and excessive demand for these stress-responsive metabolites during abiotic stress is met only by reconfiguring the metabolic network. This chapter mainly discusses drought and salt stress-specific plant metabolomic and molecular responses and gives insights into signaling network involved thereof. Metabolomics combined with conventional breeding approaches (using introgression lines) has proven to be able to map abiotic stress-responsive loci and key candidates. The role of kinases and argonautes and the prospecting of stress-responsive metabolic quantitative trait loci and alleles are also discussed. The importance of amino acid and hormone metabolism and its connection with epigenetics is reviewed.