Differential responses to salt-induced oxidative stress in three phylogenetically related plant species: Arabidopsis thaliana (glycophyte), Thellungiella salsuginea and Cakile maritima (halophytes). Involvement of ROS and NO in the control of K+/Na+ homeostasis

Salinity, which is usually associated with a nitro-oxidative stress component, is one of the major environmental factors limiting plant growth and development. Plants have thus developed specific ways of dealing with this problem. The compartmentalization of sodium (Na+) ions in vacuoles and the capacity to sharply discriminate between potassium (K+) and Na+ in order to maintain high K+/Na+ ratios are two of the most effective strategies to overcome salt stress. Plants require large amounts of K+ to maximize growth and yields. This macronutrient is involved in physiological processes such as growth, photosynthesis, osmoregulation, enzyme activation, stomatal movement, water and nutrient transport via the xylem and protein synthesis. Resistance to salt stress is mainly related to the capacity of plants to maintain improved K+ uptake despite competition from Na+. The Brassicaceae family includes species such as Arabidopsis thaliana (plant model for glycophytes), Thellungiella salsuginea and Cakile maritima (plant models for halophytes), which exhibit significant variations in response to salt stress. In this review, we provide a comprehensive update with respect to differential responses to salt stress in these three plant species, with particular emphasis on the potential involvement of reactive oxygen species (ROS) and nitric oxide (NO) in maintaining K+/Na+ homeostasis and their contribution to salt tolerance.