Plant growth-promoting rhizobacteria (PGPR) and its mechanisms against plant diseases for sustainable agriculture and better productivity

Plant growth-promoting rhizobacteria (PGPR) are specialized bacterial communities inhabiting the root rhizosphere and secretion of exudates helps to, regulate microbial dynamics their interactions with plants. These bacteria viz., Agrobacterium, Arthobacter, Azospirillum, Bacillus, Burkholderia, Flavobacterium, Pseudomonas, Rhizobium, etc., play important role in plant growth promotion. In addition, such symbiotic associations PGPRs rhizospheric region also confer protection against several diseases caused by bacterial, fungal viral pathogens. The biocontrol mechanism utilized PGPR includes direct indirect mechanisms include production antibiotic, siderophore, hydrolytic enzymes, competition for space nutrients, quorum sensing whereas, rhizomicrobiome regulation via. exudates, phytostimulation through release phytohormones auxin, cytokinin, gibberellic acid, 1-aminocyclopropane-1-carboxylate induction systemic resistance expression antioxidant defense enzymes phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenyloxidases (PPO), superoxide dismutase (SOD), chitinase β-glucanases. For suppression potent bio inoculants can be developed modulating engineering. understandings different strategies to improve strains, competence, colonization efficiency, persistence its future implications should taken into consideration.