CRISPR-CAS9 FOR IMPROVING DROUGHT TOLERANCE IN CROPS

Abstract

Drought stress is a significant limitation to crop productivity globally, and strategies are required to increase the resilience of staple crops to this important abiotic stress. In the present study, we provide validation of CRISPR-Cas9 technology for enhancing drought tolerance in wheat by targeting key drought-responsive genes (DREB2A, NCED3, and PP2C). Five genotypes (wild-type, empty-vector control, and three CRISPR-edited lines) were grown in a factorial experiment with 3 levels of soil moisture: well-watered (85% field capacity), moderate drought (55% FC), and severe drought (30% FC) with 12 replicates per treatment, n = 180. Two-way ANOVA showed significant effects of genotype, drought treatment, and their interaction on grain yield, relative water content (RWC), and water use efficiency (WUE) (p < 0.001). CRISPR_DREB2A plants showed ≈28–35% higher grain yield than the wild type in severe drought conditions. Yield edited lines presented significantly higher RWC (up to 12% increase), WUE increment, increased proline accumulation, and higher SOD and CAT activities with respect to controls. MDA levels, as an index of lipid peroxidation, were significantly lower (≈15–20%) in edited genotypes under stress conditions. Pearson correlation showed there were significant positive relationships between grain yield and RWC (r = 0.78, p < 0.001) as well as between the yield and WUE (r = 0.69, p < 0.001), but a negative relationship between the yield and MDA(r = –0.64, p < 0.001). These results suggest that engineered editing of the drought-responsive regulatory network contributes to stabilizing leaf gas exchange and yield performance under water deficit, and that CRISPR-Cas9 has great application potential for cultivating climate-resilient crops.