Advancing crop resilience to environmental stresses: Insights from epigenetic modification and CRISPR/dCas9-based editing

Plants are immobile organisms, constantly exposed to a wide variety of environmental challenges, among these, drought, salinity and extreme temperatures are the most detrimental factors that significantly affect growth and productivity, leading to substantial annual crop losses worldwide. To respond and survive such challenges, plants have developed complex adaptive mechanisms involving gene regulation at multiple levels. Epigenetic modifications, such as DNA methylation, histone modification, RNA modification, and non-coding RNAs, play a significant role in modulating gene expressions without altering underlying DNA sequences. These modifications facilitate stress-induced gene activation or repression and contribute to the establishment of "stress memory", allowing plants to respond more effectively to repeated stresses. Recent advancements in gene editing technologies, particularly CRISPR/dCas9-based systems, have enabled researchers to target these epigenetic modifications with high precision. By fusing dCas9 (deactivated or dead Cas9) with effectors such as DNA methyltransferases or demethylases or histone acetyltransferases, researchers can modify epigenetic marks that influence gene expression at specific loci, enhancing stress resilience. Most promising techniques like SunTag system have further improved the efficiency of these tools. This review explores how environmental factors influence epigenetic changes and how the knowledge gained could be used for the development of stress resilient crops. These approaches offer a promising avenue for improving desirable traits and ensuring stable crop yields, thereby supporting global food security in a rapidly changing climate.