Trehalose induced drought tolerance in plants: physiological and molecular responses

Drought stress is significant abiotic stress that limits crop growth and productivity across the globe. The intensity of drought stress continuously rises due to rapid climate change. Drought-induced alterations in physiological and bio-chemical processes by generating membrane dis-stability, oxidative stress, nutritional imbalance and leading to substantial reduction in growth and productivity. Plants accumulate various osmolytes that protect themselves from abiotic stresses' harmful effects. Trehalose (Tre) is a non-reducing sugar found in multiple microbes ranging from bacteria to yeast and in plants and it possesses an excellent ability to improve drought tolerance. Trehalose appreciably enhanced the plant growth, and counter the drought induced damages by maintaining cellular membranes, plant water relations, stomatal regulation, photosynthetic activities, nutrient uptake, osmolyte accumulation, activating stress proteins and detoxifying the reactive oxygen species (ROS) by strengthening the anti-oxidant system. Therefore, it is essential to understand the mechanism of exogenous and endogenous Tre in mitigating the drought-induced damages and to identify the potential research questions that must be answered in the future. Therefore, to better appraise the potential benefits of Tre in drought tolerance in this review, we discussed the diverse physiological and molecular mechanisms regulated by Tre under drought stress. We have a complete and updated picture on this topic to orientate future research directions on this topic.