Plant Responses to Salinity Through an Antioxidative Metabolism and Proteomic Point of View

Abstract

Salt stress is one of the most damaging abiotic stresses because most crop plants are susceptible to salinity in different degrees. According to Food and Agriculture Organization of the United Nations (FAO), about 800 million Ha of land are affected by salinity around the world. In addition to the known components of osmotic stress and ion toxicity, salt stress is also manifested as an oxidative stress with all of these factors contributing to its deleterious effects. Although salinity-induced oxidative stress has been widely described, the effect of salinity on the antioxidative system and/or ROS generation in specific cell compartments has been less studied.

In recent years, high-throughput proteomic techniques have provided new ways to explore the complex network of plant salinity response in order to identify key elements for stress tolerance acquisition. However, from an overview of the available information about plant salinity responses it can be concluded that only a small number of the salt-inducible genes reported in the literature have been identified at the protein level. Most of the salt-responsive proteins identified in these studies correspond to the categories of amino acid metabolism, energy regulation, detoxification and redox regulation.

The overexpression of genes encoding for different antioxidant enzymes is a common strategy to induce salt tolerance in crop plants. In this sense, the overexpression of H2O2-scavenging enzymes (APX, CAT), SOD, ASC-recycling enzymes or GSH-related enzymes resulted in increased salt tolerance in different plant species. In addition, some authors have used the co-expression of two or three genes encoding antioxidants to achieve salt tolerance in plants.