CRISPR/Cas9 genome editing technology in agriculture: Evolution in crop advancement, challenges and future expectancies

During the last few decades, the imergence of genome editing technology has helped Genetic Engineering and Biotechnology to revolutionize the sector of agriculture and decrease world hunger. Genome editing technology enables biotechnology researchers to modify living organisms and plants by the modification (insertion, deletion, or replacement) of the genetic material of its genome. Clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR/Cas9) is a type of genome editing technology used worldwide to edit the genomes of several crop varieties. It is based on the mechanism of acquired immunity of bacteria against viral invasion. This third-generation genome editing tool is modern, error-free, more robust, well-programmable, and has considerably higher target site specificity when compared to other genome editing tools such as ZFNs (Zinc finger nucleases) or TALENS (transcription activator-like effector nucleases), gene expression suppression by siRNA. CRISPR/Cas9 genome editing technique has revolutionized plant science and agricultural research by developing germplasms with desired traits, thus resulting in more sustainable agriculture. This review expects to show the uses of the CRISPR/Cas9 genome editing technique for agricultural crop improvement and evaluate recent examples of crops whose genomes are successfully edited and improved by CRISPR/Cas9. In addition, we present the challenges and future expectancies of the CRISPR/Cas9 genome editing technique in agricultural crop improvement.