Genetic and Molecular Mechanisms of Plant Stress Tolerance and Strategies for Improvement: A Comprehensive Review

Environmental stresses impose a significant threat on plant growth and agricultural productivity. Abiotic stresses, such as drought, salinity, and extreme temperatures, impair plant physiology and development, while biotic stresses, like those caused by pathogens and herbivores, trigger a range of defense responses. Plants have evolved intricate genetic and molecular mechanisms to cope with these challenges. The plant response to stress is governed by transcription factors (TFs), including the AP2/ERF, bZIP, WRKY, and NAC families, which regulate stress responsive gene expression. Phytohormones like ABA, ethylene, and jasmonic acid (JA) serve as crucial signaling molecules that initiate adaptive physiological changes. These signals are transmitted via signal transduction components, such as receptor-like kinases and MAP kinases, which translate external events into cellular responses. Additionally, epigenetic regulation and gene-by-environment (G × E) interactions allow plants to acquire a stress memory and exhibit adaptive plasticity, enhancing their resilience to future challenges. Improving these natural mechanisms is vital for developing stress-tolerant crops. Traditional breeding and modern techniques like Marker-Assisted Selection, Genetic Engineering, Genome Editing and Genomic Selection are used to identify and integrate desirable traits into new crop varieties. These methods enable breeders to develop more robust and stable crops, ultimately helping to ensure global food security in the face of climate change.