Soil–PCB–PGPR Interactions in Changing Climate Scenarios

Rhizosphere soil inhabits an immense diversity of microorganisms capable to perform diverse functions. Plant growth-promoting rhizobacteria (PGPR) are one of those and extensively studied to promote plant growth by various direct and indirect mechanisms. Along with growth-promoting characteristics, these ubiquitous microbes have also been well researched to remediate the contaminated environment with persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs). PGPR use PCBs as a carbon source and transform the contaminants through anaerobic reductive dechlorination or aerobic oxidation reactions taking place as a part of their metabolic processes. These bacteria convert PCBs to less chlorinated and mineralized compounds at reduced energy rather than demanding additional source of carbon to facilitate transformation. Changing climate scenarios have drastically affected the soil microbial community including PGPR and altered the soil rhizosphere dynamics. Influenced by these climatic changes, some microbial populations are overgrown, whilst others are reduced to extinction. As a result their ability to remediate the pollutants is changed. This chapter provides an overview of plant growth-promoting rhizobacteria and their involvement to remediate the PCB-contaminated environment in changing climate.