Gene Editing in Pigeonpea for Abiotic Stress Tolerance

Global food and nutritional security faces increasing pressure, particularly in South Asia and sub-Saharan Africa, as the world’s population is expected to surpass 9.7 billion by 2050. Legumes, such as pigeonpea ( Cajanus cajan L.), are vital components of sustainable agriculture due to their protein-rich seeds and nitrogen-fixing ability. Yet, their productivity is severely limited by abiotic stresses including drought, salinity, and temperature extremes, which adversely impact plant growth and yield. Conventional breeding and marker-assisted selection have advanced stress-tolerant varieties, but progress is constrained by limited genetic diversity and lengthy breeding cycles. This chapter provides an in-depth analysis of the role of genome editing, particularly CRISPR/Cas9 technology, in advancing abiotic stress tolerance in legume crops, with an emphasis on pigeonpea. Genome-editing tools-ZFNs, TALENs, and CRISPR/Cas-systems enable precise genetic modifications targeting genes involved in stress response pathways such as ion homeostasis, water regulation, and antioxidant defense, expediting the breeding process and expanding trait diversity. The integration of molecular breeding and omics technologies accelerates the identification and manipulation of key regulatory genes, while also unlocking the potential of transcriptomics, proteomics, and genomics for trait enhancement. However, obstacles remain, including recalcitrant transformation in legumes, off-target effects, and varying regulatory acceptance of genome-edited crops across jurisdictions. The progress in base editing, prime editing, and DNA-free CRISPR approaches increases specificity and public acceptance, with certain genome-edited crops classified as nongenetically modified organisms (GMO) under specific frameworks. Despite limited success in pigeon pea, genome editing–driven breeding offers promising solutions for climate-smart, sustainable agriculture, ensuring food and nutrition security in vulnerable regions. Future priorities include multiplex gene editing, improved transformation methods, and equitable access to advanced technologies, all of which could revolutionize legume farming and strengthen global food systems.