Exploring the role of sugar alcohols in enhancing plant resilience to abiotic stresses.

Plants face different types of biotic and abiotic stresses in their natural environments. Abiotic stresses include heat, cold, drought, flood, salinity, and heavy metal toxicity. They affect plant metabolism by imposing several environmental and nutritional constraints. This leads to altered physiological processes hindering the normal growth and development of plants. As a result of natural adaptations, plants have developed several cope-up mechanisms to overcome these stresses. Plants sense changes in osmolarity, salinity, and temperature to identify stress conditions. Since the discovery of stress-responsive molecules, sugar alcohols have been involved in tolerance mechanisms as their accumulation alters stress signals to elicit adaptive responses. They act as osmolytes, helping the plant in osmoregulation, a mechanism to maintain osmotic balance. They scavenge ROS molecules to reduce cellular damage. It is suggested that sugar alcohols can act as molecular chaperones, helping to stabilise protein structures and prevent misfolding. Mannitol, sorbitol, myo-inositol, and their derivatives are well-known sugar alcohols involved in abiotic stress tolerance. Although empirical research on sugar alcohols in plant abiotic stress tolerance has progressed steadily, a comprehensive comparative analysis of these studies identifying persistent research gaps is still lacking. In an attempt to fill the void, this review focuses on (a) the overview of the distribution and biosynthesis of sugar alcohols, (b) the role of sugar alcohols in plant metabolism, (c) a comprehensive insight into the role of various sugar alcohols in abiotic stress tolerance in plants, and (d) crosstalk of sugar alcohols with signalling molecules under abiotic stress. It also finds potential research gaps and explores future prospects in this area to improve stress tolerance in important crop plants.