CRISPR-BASED GENOME EDITING FOR DEVELOPMENT OF CLIMATE-RESILIENT AND DISEASE-RESISTANT CROP VARIETIES

Abstract

Global agricultural productivity is severely constrained by biotic stresses including pathogenic viruses, bacteria, fungi, oomycetes, nematodes, and insect pests which collectively account for 20–40% yield losses in staple crops worldwide. Traditional reliance on chemical pesticides and conventional breeding faces mounting challenges from pesticide resistance, ecological toxicity, and protracted breeding timelines. The emergence of CRISPR-Cas genome editing technologies has revolutionized plant biotechnology by enabling precise, site-specific genomic modifications without permanent transgene integration. This comprehensive review examines CRISPR-based strategies for engineering disease-resistant and pest-resistant crops, encompassing the molecular toolkit of Cas9, Cas12a, Cas13, base editors, prime editors, and CRISPR activation systems. Key applications include susceptibility (S) gene knockout, promoter cis-element recoding to disrupt pathogen effector binding (exemplified by OsSWEET and CsLOB1 editing), NLR receptor engineering, and manipulation of plant volatile profiles and morphological traits for insect deterrence. Advanced delivery platforms particularly nanotechnology-enabled ribonucleoprotein (RNP) complexes facilitate transgene-free genome editing while minimizing off-target effects. However, implementation faces constraints including pleiotropic fitness penalties, rapid pathogen evolutionary adaptation, and off-target cleavage risks. The regulatory landscape is evolving, with major agricultural economies increasingly exempting non-transgenic gene-edited crops from stringent GMO oversight. This review synthesizes current advances, identifies persistent bottlenecks, and outlines future directions for deploying CRISPR-edited crops toward sustainable, climate-resilient agriculture.