Rhizospheric microbiomes for agricultural sustainability

Abstract

Agricultural sustainability rests on a foundation of microbial diversity and activity. Soil consists of a rich biodiversity of microorganisms belongs to all three domains of life, i.e., archaea, bacteria, and eukarya. The rhizosphere is the plenty of extensively colonized zone of the soil due to the availability of nutrients to the microorganisms. The rhizospheric zone is one of the largest ecosystems, with the bacterial population being predominant. Bacteria in the rhizospheric region benefit the plants by stimulating their growth and productivity through diverse mechanisms, including the production of plant growth regulators and siderophores, the fixation of atmospheric nitrogen, and the solubilization of unavailable and insoluble macro-and micro-nutrients. Plant growth-promoting (PGP) rhizomicrobiomes protect the plants against phytopathogens by producing antibiotics, extra-cellular hydrolytic enzymes, prussic acid, and ammonia. Furthermore, PGP rhizomicrobiomes also help the plants under abiotic stress from cold, salinity, drought, and heavy metals by lowering the levels of inhibitory ethylene, increasing the accumulation of osmolytes in the plants, and production of the reactive oxygen species scavengers. PGP rhizomicrobiomes belong to diverse phyla of the domain archaea, bacteria, and eukarya, in which the predominant members are Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. These beneficial rhizomicrobiomes could be used as bioinculants for agricultural sustainability.Bacterial diversity in the rhizospheric region can be examined by various methodologies. A range of culture media have been designed for the isolation of culturable rhizobacteria [1]. In addition to traditional methods of isolation, bacterial diversity can be characterized at the molecular level by polymerase chain