Root Colonization by Microorganisms and The Effects of PGPR On Plant Growth: A Mini-Review

Abstract

This brief review provides a concise overview of the impact of microorganisms that colonize roots on plant growth, with a particular focus on plant growth-promoting rhizobacteria (PGPR). At the root-soil interface, microorganisms such as bacteria and fungi interact with plants, providing various advantages, including nutrient acquisition, pathogen protection, and stress tolerance. PGPR, which are bacteria that promote plant growth through mechanisms such as nitrogen fixation, potassium solubilization, induction of plant stress resistance and siderophore production, are among the most beneficial of these microorganisms. The colonization process entails chemotaxis, adhesion, and colonization of both the rhizosphere and endosphere, which are facilitated by exopolysaccharides, biofilm formation, and signaling molecules. PGPR has been shown to boost root and shoot growth, enhance nutrient and water use efficiency, and enhance plant resistance to biotic and abiotic stressors. These effects are mediated by direct and indirect interactions between PGPR and plants, which involve modulation of plant immune responses and systemic resistance. Understanding these mechanisms is critical to the exploitation of PGPR in sustainable agriculture. PGPR can reduce reliance on chemical fertilizers and pesticides, but further research is required to unravel the complex interactions between microorganisms and plants, identify key signaling molecules in root colonization, and optimize the use of PGPR in various crops. This brief review underlines the importance of root colonization by microorganisms, particularly PGPR, in promoting plant growth and sustainable agriculture.