Molecular Response of Plants to Drought, Cold and Heat Stress - A Review

The increased abiotic stresses were severe threat to world food security paving to hunger death. To combat this situation crops with high tolerance should be developed. Crop improvement mainly depends on the improvement of traits that increase yield levels with high tolerance to abiotic stresses. It is known that the expression of the trait is purely under control of gene whose expression is temporal, spatial and stimulus specific. The molecular dissection of each tolerance mechanism at transcriptional, post transcriptional, translational and signaling pathway levels helps in easy understanding of the specific traits imparting tolerance. The identification of functional markers associated with abiotic stress tolerance and manipulation of key functional or regulatory genes through molecular approaches like genetic engineering assist crop improvement with in short time. Hence, in this review we would summarize stimulus perception, signal transduction pathway (MAP kinase and ROS pathways), formation of regulatory protein, gene expression, synthesis of osmolytes (proline, glycine betaine, fructans) and other event that takes place under drought stress, heat stress and cold stress.