**7. Engineering CRISPR/Cas immune system**

Clustered regularly interspaced short palindromic repeats has been identified to be a prokaryotic defense system that combines with its associated proteins (Cas) to render an endonuclease activity that cuts the invading DNA at a particular target of interest. This specificity is determined by the sequence of DNA that matches the sequence of the RNA guide strand associated with the Cas protein. Some studies have engineered a Cas9/gRNA that targets the replicating DNA of Gemini virus that leads to agrarian crisis in tropical and subtropical climates [118–120]. Significant resistance to host can be achieved against a DNA virus by a targeted sequencespecific engineered complex of Cas9/gRNA, although the results are meant to be reproducible [121]. Long-term utilization of this strategy against a variety of genetic elements that hamper the host such as viruses can be successfully targeted [122–126].

Genome editing, brought about by *Agrobacterium*-mediated transformation or biolistic methods, gives way to a wide range of possibilities for genetic changes. Targeted modifications, specific mutagenesis, and /or modest changes can be brought about by targeting existing genes in live cells. By using CRISPR/Cas9, it is possible to create a non-transgenic gene edit that can be introgressed by conventional breeding and can yield a change that cannot be distinguished from a mutation [127]. Another application of CRISPR is that the genome editing is HDR-based that allows editing a gene from the crop's natural pool giving rise to cisgenic lines that can achieve outcomes stabilized by conventional breeding. HDR-based genome editing strategies also helps add a specific gene from an evolutionary distant organism therefore making the regulatory scrutiny mandatory similar to that of transgenics [128, 129]. Various research groups have validated CRISPR/Cas9 techniques to be straightforward, low cost, and efficient, but the accessibility of the applications of genome editing is largely dependant on democratizing genome editing, nonprofit organizations, and governmental regulations.

#### **8. Conclusion**

While recognizing the important benefits GE technologies offer, larger considerations merit attention, especially questions of public acceptability and of whether there are any long-term ecological risks different from those posed by conventional breeding. In considering such issues, it is important to remember that, not only do diverse GE strategies exist, but diverse GE manipulations are possible, ranging from very modest, targeted mutagenesis, through cisgenics and intragenics, to insertion of transgenes from other crops, from other (non-crop) plants, and from evolutionarily distant organisms. Thus, in considering socioeconomic and cultural perspectives of GE, it is important to bear in mind this diversity of strategies and applications: GE crops can differ markedly from one another. A useful GE construct may target one or a few pathogens of particular importance, but other breeding techniques still is important for tackling disease problems not targeted by available GE traits. Thus, GE should be understood, not as the best approach to addressing sustainability challenges, but as a suite of tools that capitalizes on the knowledge that biologists gain through our ongoing study of Nature. GE simply expands the breeding "toolbox," providing options to consider on a case-by-case basis for enhancing the sustainability of crop disease management.

**135**

**Author details**

*Antimicrobial Resistance with Special Emphasis on Pathogens in Agriculture*

Nitya Meenakshi Raman, Murugesh Easwaran, Rashmi Kaul, Jyotsna Bharti,

Genetic Engineering and Biotechnology (ICGEB), New Delhi, India

\*Address all correspondence to: kaultanushri3@gmail.com

Nutritional Improvement of Crops, Plant Biology Division, International Center for

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Khaled Fathy Abdel Motelb and Tanushri Kaul\*

provided the original work is properly cited.

*DOI: http://dx.doi.org/10.5772/intechopen.88440*

*Antimicrobial Resistance with Special Emphasis on Pathogens in Agriculture DOI: http://dx.doi.org/10.5772/intechopen.88440*
