Genomic Mechanisms of Plant Adaptation to Salinity and Drought Stress: Genes, Networks, and Evolutionary Implications

Salinity and drought stresses induced by climate change pose critical threats to global food security, necessitating a comprehensive insight of plant adaptive mechanisms at the genomic level. This review brings together recent advances in identifying genes, regulatory networks, and evolutionary strategies underlying plant responses to osmotic stress. We discuss key transcription factor families (DREB, NAC, MYB, and WRKY), ion transporters (SOS pathway, NHX, and HKT), genes involved in osmolyte biosynthesis, and reactive oxygen species (ROS) scavenging systems. Recent genomic studies have revealed extensive expansions of gene families, neofunctionalization events, and convergent evolution across plant lineages. Multiomics integration has illuminated complex regulatory networks involving microRNAs, long noncoding RNAs (lncRNAs), and epigenetic modifications that fine-tune stress responses. We examine natural variation in stress tolerance, highlighting genomic signatures of selection in halophytes and xerophytes that provide insights for crop improvement. Pangenomic analyses revealed that significant structural variations and presence-absence variations contributed to stress adaptation. Finally, we discuss evolutionary trade-offs, the impact of domestication on stress resistance, and future directions for leveraging genomic knowledge through precision breeding, gene editing, and systems biology approaches to develop climate-resilient crops.