Direct mechanism of PGPR for promoting plant growth: Current perspective

PGPR, a plant growth-promoting rhizobacterium in the rhizosphere, stimulates growth and development through various mechanisms such as mineral nutrient availability, phytohormone regulation and phytopathogen control. PGPR inoculant’s establishment, survival and persistence depend on these characteristics and a complex chain of interactions in the rhizosphere. Soil is a damp habitat containing decomposed carbon and abundant microorganisms. Agriculture relies heavily on the rhizo-microbiome, as root exudates and plant cell detritus create specific microbial colonization patterns. Secondary metabolites, antibiotics, hormones and signalling chemicals are the extracellular molecules produced and regulated by the rhizomicrobiome. The microbial composition of rhizomes affects soil texture. Research indicates that PGPR inoculates plants, promotes their growth and development. PGPR modifies plant physiology and improves nutrient intake and root activity. The plant biochemical pathways that contribute to this phenomenon are not yet fully understood. New research has revealed how PGPR signaling triggers plant responses at both local and systemic levels. There is limited understanding of how PGPR mechanisms and chemicals affect metabolic pathways in the roots. This review focuses on understanding the PGPR mechanism and the chemicals that affect root-microbe interactions.