ABSTRACT
This chapter describes the important plant growth-promoting rhizobacteria (PGPR) species and their mode of action/application/role in improving sustainable agriculture. The application of microbes to improve the plant nutrients availability is a vital practice and needed for agriculture ecosystem. The use of PGPR for sustainable agriculture has increased globally since it has the abilities to release beneficial phytohormones to promote crop physiological growth and development. PGPR can benefit plant root by both direct and indirect mechanism within the soil microhabitat. Soil is a complex environment offering a variety of microhabitats for which microbial diversity in soil is much greater than that found in other environments. Many microbes inhabit the pores between soil particles; others live in association with plants. Microbe—plant interactions can be broadly divided into two classes: an epiphyte is a microbe that lives on the surface of plants; and those colonize internal plant tissues are called endophytes.
