*Review* **Genome Editing and Improvement of Abiotic Stress Tolerance in Crop Plants**

**Rakesh Kumar Yadav 1, Manoj Kumar Tripathi 1,2,\*, Sushma Tiwari 1,2, Niraj Tripathi 3,\*, Ruchi Asati 1, Shailja Chauhan 1, Prakash Narayan Tiwari <sup>2</sup> and Devendra K. Payasi <sup>4</sup>**


**Abstract:** Genome editing aims to revolutionise plant breeding and could assist in safeguarding the global food supply. The inclusion of a 12–40 bp recognition site makes mega nucleases the first tools utilized for genome editing and first generation gene-editing tools. Zinc finger nucleases (ZFNs) are the second gene-editing technique, and because they create double-stranded breaks, they are more dependable and effective. ZFNs were the original designed nuclease-based approach of genome editing. The Cys2-His2 zinc finger domain's discovery made this technique possible. Clustered regularly interspaced short palindromic repeats (CRISPR) are utilized to improve genetics, boost biomass production, increase nutrient usage efficiency, and develop disease resistance. Plant genomes can be effectively modified using genome-editing technologies to enhance characteristics without introducing foreign DNA into the genome. Next-generation plant breeding will soon be defined by these exact breeding methods. There is abroad promise that genome-edited crops will be essential in the years to come for improving the sustainability and climate-change resilience of food systems. This method also has great potential for enhancing crops' resistance to various abiotic stressors. In this review paper, we summarize the most recent findings about the mechanism of abiotic stress response in crop plants and the use of the CRISPR/Cas mediated gene-editing systems to improve tolerance to stresses including drought, salinity, cold, heat, and heavy metals.

**Keywords:** abiotic and biotic stress; CRISPR; mega nucleases; TALEN; ZFN
