Chapter 17 – Osmolyte Dynamics: New Strategies for Crop Tolerance to Abiotic Stress Signals

Osmolytes and osmoprotectants have long been identified as pivotal abiotic stress busters because they help plants overcome extremely harsh environmental conditions by constant cellular homeostatic monitoring. This group mainly consists of sugars, polyols, amino acids, and betaines. Together, they shield plants by exercising a number of physiological responses such as membrane integrity strengthening, enzymatic/antioxidant activity balancing, and water adjustments under various abiotic stresses (e.g., temperature fluctuations, water deficit, salinity, heavy metals) and, more recently, pesticide exposure. Crop plant cultivation across the globe needs such comprehensive protection strategies against a vast array of ever-changing environmental conditions by developing tolerance at genetic and molecular levels. Currently, this is being achieved via osmoprotectant genetic engineering of plant genomes and exogenous application of antistress agents to crop plants to obtain high-yield, stress-resistant varieties. A newer modification to this two-dimensional approach is osmoprotectant activation via “omics”—an integral approach comprised of genomics, metabolomics, and transcriptomics. This chapter gives a cumulative account of their biosynthesis, classification, and functioning with respect to transgene induction, exogenous application, and omic approaches for an improved agricultural dimension.