The Role of Catabolic Programs in Plant Adaptation to the Toxic Effects of Acute Chloride Salinity

The accumulation of inorganic salts in the soil solution has a pronounced toxic effect on most higher plants that lack specific protection mechanisms. An excess of sodium cations and chloride anions leads to disruptions in normal cell function, reduced growth, and decreased yields of cultivated plants. Salt tolerance mechanisms represent a complex system of adaptive processes aimed at neutralizing the toxic effects caused by increased salt in the surrounding environment. The multicomponent and multigene control of the plant response to salt stress at the cellular, organ, and organism levels makes the selection of salt-tolerant genotypes a challenging task. This review examines the molecular and cellular mechanisms activated in plants when the concentration of sodium and chlorine ions sharply increases in the rhizosphere substrate. The pathways of ion uptake, ion channels, and transporters that maintain ionic homeostasis in root and leaf mesophyll cells are analyzed. Salt perception mechanisms and the main signaling system that transmits salinity signals from the root system to the plant shoots are briefly defined. Special attention is paid to cytological adaptation mechanisms, including cellular sensors and signaling cascades that trigger the physiological response to acute salinization, as well as autophagy — the process of regulated degradation of damaged cellular structures and macromolecules, which plays an important role in the adaptation of plants to salt stress. The information on the main types of nuclear and DNA structure disruptions that develop under salinity stress and lead to programmed cell death is also included. Thus, the review covers the primary mechanisms of glycophyte adaptation to salt stress and highlights the potential of studying catabolic programs for developing strategies to enhance the tolerance of agricultural crops.