Alleviation of drought stress in plants through microbial interventions

Abstract

Drought is a serious and common threat to plant survival worldwide and in getting intensified due to global warming and decreasing water levels thereby possessing challenges on food security. The responses of plants to changing environment are complex. Physiological responses of plant towards drought adjustment include stomatal closure, increase in abscisic acid (ABA) content, accumulation of compatible solutes, increased expression of aquaporin, etc. Drought stress generates a flood of reducing power in plant that is directed towards synthesis of highly reduced compounds like isoprenoids phenol and alkaloids. Microbes too respond to water stress by reallocating resource from growth to survival which can be either osmolyte synthesis, chaperons to stabilize protein, accumulation of amino acid, production of exopolysachride (EPS) and so on. However, all adaption and acclimatization strategies are at physiological cost at the organism level which can affect ecosystem functioning at large. Plant growth promoting microbes (PGPM) are capable of modulating the physiological response of plants to water stress and overcome yield barrier. Availability of water and nutrients to plant is determined by the rhizospheric water potential which can be manifested to some extend by PGPM. PGPM may exert their effect on plant through nitrogen fixation, production of siderophores, phytohormones, exopolysaccharides, solubilization of nutrients, induction of pathogen resistance or decreasing pollutant toxicity. Plants growing in soil that naturally undergo variable dry and wet periods are less influenced by water stress.While research supports that plant growth promoting microbes can be an ecofriendly alternative to combat drought stress, a better understanding of physiological responses of microbes to stress can develop a stronger and resilient ecosystem. © 2017 by Nova Science Publishers, Inc. All rights reserved.