Role of PGPR in Sustainable Agriculture: Molecular Approach Toward Disease Suppression and Growth Promotion

Abstract

Plant concomitant bacteria play a substantial part in plant growth promotion and disease suppression. However, to deliver the best up to their capacity, efficient colonization of the plant roots is of utmost importance. The microbes introduced to the soil, either as a single inoculant or as a consortium, interact with host plant and initiate cascade of reactions which result in plant growth and defense responses. PGPR produce extensive variety of secondary metabolites, allelochemicals, which may work as starting signals or enhancing the necessary reactions. Their action methodology and molecular machineries offer a great cognizance for their application in control of crop diseases. These genes are either upregulated or downregulated, and their expression decides the fate of plant growth and mechanism by which plant resists the disease. Number of genes which will be expressed, encode several metabolites responsible for better growth and synthesis of antimicrobial compounds. Recent developments in expression profiling methods and availability of extensive genome sequence data have permitted important advancements in understanding of responses toward disease resistance in plants. In the later part, we discussed how DNA microarray fits with the current part of PGPR in plant growth promotion and disease resistance. Overall, this chapter will help to better understand the molecular mechanisms behind plant and rhizobacteria interactions.