Salinity Stress-Dependent Coordination of Metabolic Networks in Relation to Salt Tolerance in Plants

Abstract

The major environmental stress, salinity, results in other secondary stresses such as osmotic stress, oxidative stress, and ionic stress leading to physiological, biochemical, and molecular alterations in plants. Many plants develop mechanisms, either to exclude salt from their cells or to tolerate its presence within the cells. Salinity stress signal initiates multiple secondary signals in plants leading the activation of several physiological and biochemical strategies for gradual adaption of plants against salt stresses. The essential processes leading to plant adaption to salt stress include metabolic adjustment, toxic ion homeostasis, and osmotic adjustment. During the salinity stress, active accumulation of osmotic solutes such as soluble carbohydrates, proteins, and free amino acids is one of effective stress tolerance mechanisms as accumulation of these osmotic solutes lowers osmotic potential within cells and tissues. Environmental constrains have ultimate impact on plant growth, although these can be overcome by production of various metabolites through appropriate genes of the cells. In this chapter, salt tolerance and subsequent metabolic alterations in plants are under the following aspects: impact and response of plants for abiotic stress specifically to salinity stress; the morphological, biochemical, and metabolic adjustments of plants during salinity stress; role of rhizosphere microbes in plant stress tolerance; and expression of salt tolerance genes. This chapter will help to understand the mechanism of plant salt tolerance along with biochemical and metabolic changes required to adapt plants for salinity stress.