Microbial Mitigation of Abiotic Stress in Crops

Abstract

Abiotic stresses such as drought, salinity, temperature, flooding and heavy metal toxicity reduce crop yield. About 64% of land worldwide is affected by drought. The lack of moisture in crops may lead to 50% yield loss, and increases soil salinity levels. Therefore, the use of plant growth promoting rhizobacteria for increasing plant stress tolerance appears as a sustainable strategy. Here we review abiotic stress tolerance mediated by plant growth promoting rhizobacteria in plants with focus on phytohormones, improved physiological attributes, root system architecture and regulation of the osmotic balance. Improved antioxidant activity result in reduced oxidative damage, which promotes plant growth, and nutrient and water uptake. Other extracellular secretions trap ions and moisture and improve the growth environment. Emissions and elicitors function as signaling molecules that induce genes and transcription factors belonging to the stress responsive pathways. The use of plant growth-promoting rhizobacterial bioinoculants is effective in enhancing tolerance to crop abiotic stress. The formulations and application of these microorganisms is promising for climate smart agriculture.