Research on the regulation mechanism of salt tolerance in wheat

Wheat (Triticum aestivum L.) is an important staple crop in the world, and salinity-alkalinity stress is one of the major abiotic stresses that limit wheat production, especially under climate change and seawater intrusion. As a key staple crop, wheat exhibits relatively low salt tolerance, making the improvement of its salt tolerance an urgent task. The ion toxicity induced by salt stress is primarily caused by the excessive accumulation of Na+ and Cl-, and depletion of K+, resulting in the disruption of ion balance. Na+ is the most abundant soluble cation in saline soils, which can cause damage to plants through osmotic stress and is accompanied by ionic toxicity. Under salt stress conditions, Na+ diffuses with water to plant roots and then is transported upward to stem tissues through transpiration. When the salt concentration in the soil exceeds the plant's tolerance threshold, the translocation of excess Na+ from the roots to the stem leads to the accumulation of Na+ in the leaves or other photosynthetic tissues. This accumulation adversely affects crops by inhibiting photosynthesis, damaging cell membrane permeability, and disrupting protein synthesis, ultimately reducing yield. Therefore, identifying genes associated with salt tolerance is a crucial prerequisite for the breeding of salt-tolerant wheat varieties. In this paper, we reviewed most of the studies on wheat salt-alkali tolerance conducted in the past five years, focusing on the multi-level inhibitory effects of salt stress on wheat growth and development, including osmotic imbalance, ion toxicity, and oxidative damage; physiological adaptation strategies for wheat salt tolerance (ion compartmentalization, osmotic regulation, reactive oxygen species scavenging); and key molecular regulatory networks (such as SOS, HKT gene families). It also discusses the application progress of modern breeding technologies, including molecular marker-assisted selection, genome editing, and multi-omics integration, in the development of salt-tolerant wheat varieties. Furthermore, the article explores emerging research directions such as multi-omics analysis and microbiome interactions, providing theoretical basis for breaking through the bottleneck of salt-tolerant breeding.