Gene editing to improve drought tolerance

Abstract

Drought is by far one of the main agricultural problems affecting crop production worldwide, generating even more economic losses than all biotic factors combined. Humankind has pursued the improvement of crops to enhance plant productivity under water-limiting conditions since the dawn of agriculture, initially through conventional breeding and more recently, using tools such as transgenesis and gene editing. Among gene editing techniques, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system has seen a boom in plant breeding, thus, contributing to improve tolerance to biotic and abiotic stresses. This review provides a broad view of drought tolerance mechanisms. The molecular factors mediating this complex quantitative trait and biochemical mechanisms related to drought-tolerant phenotypes are described. Likewise, gene editing tools to confer drought tolerance, limitations, and further direction of gene editing technique with CRISPR/Cas are discussed. Considerations about epigenetics of drought tolerance are mentioned as a new emerging mechanism to understand memory to stress and its possible application to obtain stress-tolerant crops via genome editing.