CRISPR/Cas-Mediated Abiotic Stress Tolerance in Crops

To meet the food requirements of increasing human population in light of predicted climate change and extreme abiotic stress, crops with higher yield and enhanced abiotic stress tolerance are urgently needed. Previously, classical breeding and conventional genetic engineering led to limited success. However, these methods have several limitations, including time-consuming processes, ethical factors, environmental factors, and the especially complex nature of abiotic stresses. Over the last decade, CRISPR/ has emerged as powerful genome editing tool with immense potential to develop crops with enhanced stress tolerance. CRISPR has been successfully used for targeted genome modifications in model and crop plants. In this chapter, we briefly discuss design, delivery, and footprinting of CRISPR-based genome editing tools. We discuss how CRISPR/-based mutagenesis makes it possible to decipher new genes to increase our understanding of stress-regulatory mechanisms in plants and develop stress-tolerant crops. In addition, we summarize the prospects of CRISPR-mediated deletions, insertions, and multiplex genome editing to develop climate-resilient crops. We outline CRISPR applications to develop stress-tolerant crops using transcriptional regulation through CRISPRi and CRISPRa. Furthermore, we highlight the potential of CRISPR-based epigenome editing, base editing, and directed evolution to develop stress tolerance in crop plants. We also discuss how CRISPR-directed RNA editing would help in transcriptional control under abiotic stress conditions without creating DNA double-strand breaks. Finally, we discuss challenges and future prospects of CRISPR edited crops for sustainable agriculture.