New prospects on the horizon: Genome editing to engineer plants for desirable traits

Targeted genome editing tools using artificial nucleases delivers progressive biotechnological techniques that paves a way to address the fundamental basis of a biological system. Genome editing enables specific and proficient modifications targeted at precise loci in an organism’s genome. A major stride for genome editing is to generate a double stranded DNA break that is unique to a specific target gene. This is primarily accomplished by custom designed endonucleases, which either enable gene targeting through homologous recombination (HR) or allow site directed mutagenesis by non-homologous end joining (NHEJ) repair mechanism. Genome editing tools have been deployed in various model and non-model plants for functional characterization of genes and improvement of agricultural traits. This comprises the generation of plants with compositional characteristics and traits that improve quality and productivity of crops as well as impart tolerance to biotic and abiotic stresses. During the last few decades, there has been a revolution in genome editing technologies with the advent of meganucleases, zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR). The implementation of these robust genome editing tools with respect to their adaptation, pliability and end use has provided a magic bullet in agricultural biology. This review focusses on these revolutionary methods in relevance to their application in crop improvement.