The Modification of Abscisic Acid and Cytokinin Signaling with Genome Editing to Increase Plant Drought Tolerance

Abstract

Due to climate aridization, the need to increase the resilience of plant productivity lo water stress becomes urgent. Abscisic acid and cytokinins have opposing biological roles during water deficit and post-drought recovery, but both these regulators can be utilized to maintain plant productivity under water stress. Downregulation of abscisic acid biosynthesis and signaling can aid in the maintenance of photosynthesis, growth, and productivity in plants, although increasing the susceptibility to severe stress. Cytokinin upregulation can maintain photosynthesis and productivity during water stress and aid recovery processes, whereas downregulation can lead to increased root growth, thus improving plant water balance, nutrient absorption, and hence productivity in water-limited conditions. The use of modern genome editing methods makes it possible to specifically modify genes involved in the implementation of complex traits in plants, such as resistance to stress factors. This review will examine the main areas of work on genome editing of gene families involved in plant responses to water deficiency using CRISPR/Cas technologies. Our current work on editing the ABF gene family, encoding transcription factors for ABA (AREB1/ABF2, AREB2/ABF4, and ABF3), as well as the CKX gene family (CKX1 and CKX4), encoding cytokinin oxidase/dehydrogenases, will be presented.