Impact of Plant-Microbe Interactions on Plant Metabolism Under Saline Environment

Abstract

Soil salinity is a significant abiotic stress causing a remarkable decrease in crop production. The plant-microbe interactions can affect the metabolism of plant under saline stress causing changes in major processes like germination, growth, and nutrient imbalance. Changes also can be seen in root and shoot induction hormone levels during growth. There can be difficulty in uptake of water due to reduced osmotic potential due to osmotic dormancy. Plant growth-promoting rhizobacteria (PGPR) improve and enhance plant growth and yield. Production of different compounds results in increased root length and number of root tips. Many actinomycetes are also components of rhizosphere microbial communities and play a major role in plant growth. Presence of ACC deaminase under saline condition causes increase in chlorophyll content and seed germination in okra plants. These microorganisms also help in reducing ethylene stress. This chapter also discusses about a new study on induced systemic tolerance to salt stress with Arabidopsis using Bacillus subtilis. The plant-associated mycobiota that include various mycorrhizal fungi and other fungi play a major role in stress tolerance. The tolerance of plant to salt stress is found to be positively correlated with antioxidant enzyme activity. These antioxidant enzymes and ROS scavengers are responsible for direct or indirect removal of ROS. Soil salinity is a major factor that limits the productivity of crops, it has been proposed that half of the land in the world that is suitable for growth of crops will be salinized by 2050, and improved strategies are being developed which include different plant-microbe interactions that can assist plant growth under salt stress. Thus, the aim of the present chapter is to focus on the impact of plant-microbe interactions on plant metabolism under saline environment and also on the involved mechanisms.