Vol. 5, Issue 2, Part B (2019)

Abstract
Metabolites reflect the integration of gene expression, protein interaction and other different regulatory processes and are therefore closer to the phenotype than mRNA transcripts or proteins alone. Amongst all –omics technologies, metabolomics is the most transversal and can be applied to different organisms with little or no modifications. It has been successfully applied to study the response of plants under different kinds of stresses in order to find particular patterns associated to stress tolerance. These studies have emphasized the essential involvement of primary metabolites, primarily includes sugars, amino acids and Krebs cycle intermediates as direct markers of photosynthetic dysfunction as well as effectors of osmotic readjustment. On the contrary, secondary metabolites are more specific of genera and species and respond to particular stress conditions as antioxidants, Reactive Oxygen Species (ROS) scavengers, coenzymes, UV and excess radiation screen and also as regulatory molecules. In addition, the induction of secondary metabolites by several abiotic stress conditions could also be an effective mechanism of cross-protection against biotic threats, providing a link between abiotic and biotic stress responses. It is also known that the metabolomics has become a powerful tool in agriculture and food science and has been used to characterize metabolic changes in plants after biotic and abiotic stresses as well as biotic contamination of foods.