Highlights of advances in drought stress-induced plants resistance mechanisms

Drought represents a major abiotic stress that influences plant metabolism and growth. It interferes with essential physiological functions, biochemical pathways and molecular processes. To cope with this, plants have adopted complex strategies for circumventing the adverse effects of drought; which include drought tolerance, drought escape and drought avoidance. Across the globe, scientists have postulated ways and mechanisms for alleviating drought stress; which include efficient use of water, use of soil microbes to promote plant growth by enhancing nutrient uptake, addition of phytohormones to coordinate various physiological and biochemical adjustments such as stomatal regulation, osmotic balance, antioxidant defense activation, and stress responsive gene expression, and new breeding techniques. Advances in genome editing tools such as CRISPR-Cas9 and prime editing, offer new opportunities for breeding for drought-tolerant crops. This review highlights the mechanisms in which plants responds to drought with Abscisic acid (ABA) functioning as the central integrator of drought signaling coordinating various cellular mechanism. It also highlights how the various phytohormones function through extensive crosstalk and not independently. In addition, the review highlights how drought tolerance is governed by coordinated regulation of physiological, biochemical and molecular mechanisms. Despite all the advancements, major challenges still remain in drought tolerance, which include the complexity of the genotype X environment interactions, field evaluations of laboratory findings and understanding of the cross-talk among physiological, biochemical and molecular pathways. Opportunities for further research include multi-omics studies, field studies, quantitative trait analysis (QTL) and genome editing. In conclusion, due to the polygenic nature of drought, a holistic approach in the understanding how physiological, biochemical and molecular mechanism synergistically contribute to drought tolerance is thus required in order to develop drought tolerant plants.