Clustered regularly interspaced short palindromic repeats (CRISPRs).CRISPR- associated 9 (Cas9) is a prokaryotic molecular immunity system against invading viruses and has been harnessed as a powerful tool for targeted genomic editing. It has become most promising and extremely versatile tool for crop improvement for providing sustainable productive agriculture for better feeding of rapidly growing population in a changing climate. Bacterial and archaeal genomes acquire short pieces of DNA, called spacers, from invading viruses and incorporate these spacers within their genome, where they serve as a form of molecular memory. During subsequent infections, spacers are transcribed as part of the CRISPR array after transcription and maturation, CRISPR RNA guides the Cas9 endonuclease to scan invading DNA and cleave the target sequence. For targeted modification of genomic sites, transgenic production of a single guide RNA (sgRNA) provides specificity to the Cas9 endonuclease, allowing targeted cleavage of specific DNA sequences in eukaryotic cells. Recent work used the CRISPR/Cas9 system for targeted improvement of crop traits. The utility of CRISPR/Cas9 technology for generating novel genetic resistance to the poty virus TuMV was demonstrated in A. thaliana by deletion of a host factor, eIF (iso) 4E, which is strictly required for viral survival. Development of virus resistance in cucumber (Cucumis sativus L.) was also demonstrated by disrupting eIF4E, and developing non transgenic heterozygous eIF4E mutant plants. These non transgenic plants developed partial resistance to an ipomo virus (Cucumber vein yellowing virus) and two poty viruses (Zucchini yellow mosaic virus and Papaya ring spot mosaic virus- W). The CRISPR/Cas9 system has mostly been used to engineer immunity in model plants. Several viral diseases that cause devastating losses of many economically important crops around the world still must be addressed. This technology has opened new ways for studying plant-pathogen interaction and designing broad spectrum durable resistance against viruses. Novel host factors can be identified for CRISPR/Cas9 mediated editing which interacts with the virus proteins using molecular dynamic studies of computational biology to provide broad spectrum resistance against rapidly evolving viruses.