Abiotic stress, triggered by global climate change and human activities, continuously impacts plant health and productivity. With the global population booming and humanity’s heavy reliance on plant resources, the escalating abiotic stress in plants, especially salt stress—a common and lethal environmental stress factor—poses a severe threat to ecosystem stability and food security. For years, researchers worldwide have been dedicated to deciphering the mechanisms of salt stress and seeking effective solutions.
Recently, a review paper titled “Molecular insights into salt stress adaptation in plants” was published in Plant, Cell & Environment. This paper elaborates on the latest advancements in the molecular regulatory mechanisms of plant salt stress, covering aspects such as salt absorption and transportation, salt sensing and signal transduction, hormonal regulation, epigenetic modifications, genetic adaptation, and post-translational modifications. By systematically integrating the key progress in current plant salt stress research, the review clearly identifies the achieved results and the areas that urgently need breakthroughs, providing a theoretical basis for enhancing plant stress resistance and ensuring their survival in harsh environments.
Plants can be categorized into two types according to their salt tolerance. One type is highly sensitive to salt, known as glycophytes, while the other type exhibits high salt tolerance and is called halophytes. The primary cause of salt stress is the excessive accumulation of Na⁺ in plants. Plants absorb Na⁺ through their roots via various channels and gating mechanisms, including non-selective cation channels (NSCC), high-affinity potassium transporters (HKT), Na⁺/H⁺ exchangers (NHX), as well as voltage-dependent and voltage-independent cation channels. The excessive accumulation of Na⁺ ions is regulated through transportation from the roots to other plant parts, efflux, or compartmentalization, thus maintaining ion homeostasis and preventing salt stress.
Plants detect Na⁺ accumulation using signals such as water changes, ion balance, and reactive oxygen species (ROS) accumulation. Elevated Na⁺ levels trigger complex signaling pathways, including calcium signaling, the salt overly sensitive (SOS) pathway, ROS signaling, and the mitogen-activated protein kinase (MAPK) cascade, to cope with salt stress, restore internal balance, minimize damage, and enhance their adaptability to harsh conditions.