Mitigation Strategies for Abiotic Stress Tolerance in Plants Through Stress Tolerant Plant Growth-Promoting Microbes

Abstract

Crop production is adversely affected by a number of abiotic stresses that arise due to anthropogenic activities and inherent edaphic factors. Several agronomic strategies have been used to mitigate the abiotic stresses to increase crop yield. Recently, researchers have been intrigued by the rhizosphere associated microorganisms from the plants growing in extreme environments. Bacterial strains belonging to the phyla Proteobacteria, Actinobacteria,Firmicutes, and archaeal strains related to the phyla Crenarchaeota and Euryarchaeota were abundantly found in the rhizosphere of plants growing under abiotic stress conditions. The well-known PGP strains include Bacillus, Rhizobium, Frankia, Azotobacter, Azospirillum, Paenibacillus, Serratia, Pseudomonas, and Klebsiella. Plant associated microbial communities promote plant growth under extreme conditions by mineral solubilization, phytohormones production, nitrogen fixation, siderophore, and HCN production. A number of rhizobacterial and archaeal strains have the ability to enhance plant defense mechanisms against different bacterial and fungal pathogens by the production of different antibacterial and antifungal compounds. Meta-omics approaches including metagenomics, metatranscriptomics, andmetaproteomics are commonly used for microbial diversity analysis and microbe-mediated stress alleviation in different crops growing under extreme conditions. This chapter gives an overview of the archaeal and bacterial diversity residing in the rhizosphere and root endosphere of plants growing under extreme environments and also explained different microbe-mediated mitigation strategies in plants under various abiotic stresses.