Refining osmosensing mechanisms for crop resilience: insights from glycophytes and halophytes

Salinity and drought are major global challenges threatening crop productivity and ecosystem diversity, causing annual losses exceeding US$100 billion. These stresses share a common factor: osmotic stress imposed on plants. While extensive research has explored plant osmotic adjustment mechanisms, the processes underlying osmosensing in plant roots and how this sensing translates into adaptive responses remain poorly understood. This study aims to bridge this gap by examining the structure and function of various putative osmosensors (e.g., histidine kinases, mechanosensitive ion channels, phospholipase enzymes, and receptor-like kinases) across halophytes and glycophytes—two plant groups with contrasting salinity tolerance. We conducted a thorough bioinformatics analysis to explore the molecular evolution and structural diversity of these osmosensors in both plant groups. Our findings reveal that the evolution of putative osmosensors is highly conserved between glycophytes and halophytes, with notable divergence between monocot and dicot species within both groups. While halophytes do not exhibit distinct protein families during their evolutionary process, differences in conserved amino acids between glycophytes and halophytes may significantly influence osmosensing, signaling, and stress adaptation. Importantly, halophytes possess more copies of osmosensor-related genes compared to glycophytes. These findings offer valuable insights for breeding climate-resilient crops, highlighting potential pathways to enhance stress tolerance through genetic improvements.