Osmolytes metabolism in plant system as sensors under adverse conditions

Osmolytes play a crucial role in plant responses to abiotic stress, with their synthesis and accumulation significantly increasing under adverse conditions such as drought, salinity, and heavy metal. However, not all plants produce every type of osmolytes. The specific osmolytes synthesized are influenced by the type of stress, plant species, and other environmental factors. Osmolytes have been classified into distinct groups based on their chemical structure, including small carbohydrates, polysaccharides, sugar alcohols (polyols), amino acids, methylated proline-related compounds, quaternary ammonium compounds, and tertiary sulfonium compounds. Beyond their roles in osmotic adjustment and maintaining turgor pressure, osmolytes perform crucial metabolic functions acting as sensors within metabolic pathways, and contributing to plant resilience upon both abiotic and biotic stresses. Recent studies suggest that manipulating osmolyte levels through genetic modification offers a promising bioengineering strategy to enhance plant stress tolerance. Thus, this chapter provides a comprehensive and updated overview of osmolytes metabolism, their role as metabolic sensors under adverse conditions, and their potential applications in bioengineering through genetic modification to improve plant stress resilience.