Plant Growth Promoting Bacteria in Rhizomicrobial Environments

Abstract

Microbes are associated with every plant tissue and in combination with the plant form the halobiont. Plants
regulate the composition and activity of their associated bacterial community carefully. These microbes provide
a wide range of services and benefits to the plant in return the plant provides the microbial community with
reduced carbon and other metabolites. Soils are generally a moist environment rich in reduced carbon which
supports extensive soil microbial communities. The rhizomicrobiome is of great importance to agriculture
growing to the rich diversity of root exudates and plant cell debris that attract diverse and unique patterns of
microbial colonization. Microbes play key roles in nutrient acquisition and assimilation improved soil texture
secreting and modulating extracellular molecules such as hormones secondary metabolites antibiotics and
various signal compounds leading to enhancement of plant growth. The microbes and compounds they secrete
constitute valuable bio stimulants and play vital roles in modulating plant stress responses. The research has
demonstrated that inoculating plants with plant-growth promoting rhizobacteria that can be an effective
strategy to stimulate crop growth. These strategies can improve crop tolerance for the abiotic stresses such as
drought heat and salinity likely to become more frequent as climate change conditions continue to develop. This
discovery has resulted in multifunctional PGPB based formulations for commercial agriculture to minimize the
use of synthetic fertilizers and agrochemicals. This review introduces the concept and role of the
phytomicrobiome and the agricultural context underlying food security and mechanisms of plant growth
promotion by PGPB including signal exchange between plant roots.