Plant rhizospheric soil is rich in microbes due to the release of exudates that serve as food for microbes. Metabolic activity of the root system and the nature of soil influence the microbial population. Through the process of mineraliza - tion, microbes assimilate the nitrogen and other essential nutrients. Specific strains of bacteria that inhabit the rhizospheric region are specifically termed as “plant growth promoting rhizobacteria” and therefore, used as “biofertilizers” to manage soil fertility. This group of bacteria is also termed as “biocontrol agents” due to their potential to suppress pests and pathogens that attack crop plants. In the agriculture field soil, earthworms also play a key role in nutrient cycling through their interaction with soil microbes. Therefore, earthworm cast microbi - ome receives greater attention. In this chapter, we propose to describe the bio - logical role of rhizospheric soil and vermicompost bacteria and their mechanisms that mediate soil fertility, plant growth promotion and biocontrol of pests and pathogens.