Genome Editing: Revolutionizing the Crop Improvement

Modern biotechnology is progressed to sequence-specific, site-directed, precise, and safe strategies for genetic manipulation. The genome-editing strategy is being proposed as one of the most promising tools for genomic study and crop improvement. The basic mechanism involved in genetic manipulations through programmable nucleases is recognition of target genomic loci and binding of effector DNA-binding domain (DBD), double-strand breaks (DSBs) in target DNA by the restriction endonucleases (FokI and Cas) and the repair of DSBs through homology-directed recombination (HDR) or non-homologous end joining (NHEJ). The less efficient and more precise HDR results in the replacement of nucleotides, whereas the more efficient and error-prone NHEJ results in the insertion or deletion of nucleotides. The genome-editing strategies like ZFN, TALEN, and CRISPR/Cas involved in genome editing are being employed to add the desirable trait(s) and remove the undesirable. The impact of gene editing application in crop improvement has proven it the next-generation tool to enhance agricultural productivity. The modifications in crop plants include biotic and abiotic stresses, nutritional improvements, alteration in phenotype, and other characters such as crafting male sterility, haploid production, and increase in yield. The repurposing of CRISPR applications by catalytically inactive Cas9 marks CRISPR as an indispensable tool for genome editing and beyond in biological research. However, the genome-edited plants may have unintended alteration(s) that create biosafety risks. The tools are eventually progressing for more accuracy and efficiency to ensure the safety of consumers and the environment. This article is an attempt to review these genome-editing strategies, the biochemistry attributed to application in crop improvement, and the associated challenges.