Probiotics for Plants: Importance of Rhizobacteria on Aboveground Fitness in Plants

Coordinated interactions between plants and microbes are crucial for maximum fitness and survival of both the host and microbial organisms in a given environmental system. Soil microbes are known to play a major role not only in the composition and uptake of nutrients, but also in conferring host plants partial immunity against a wide range of foliar diseases by triggering defense responses. However, the mechanisms involved in inducing resistance against pathogens by soil microbes have not been elucidated, even though the effect of beneficial microbes on plants has been discussed in the literature. Through this chapter, we intend to provide a fundamental insight into the integration of communication mechanisms, not only at the interfaces of plant–microbes interactions, but also at the whole plant level.