Functional Role and Mechanism of PGPRs, AMFs and Endophytes in Improving Host Resistance Against Plant Pathogens

Plant pathogens pose a significant threat to agricultural productivity and food security worldwide. To combat these diseases, researchers have explored the potential of beneficial plant-associated microorganisms, including Plant Growth-Promoting Rhizobacteria (PGPRs), Arbuscular Mycorrhizal Fungi (AMFs), and Endophytes. This Chapter provides an overview of the functional mechanisms by which these microorganisms enhance host resistance vs plant pathogens. PGPRs, through multiple mechanisms such as antimicrobial compound production, nutrient and space competition, and systemic resistance induction, promote plant growth and confer protection against pathogens. AMFs establish mutualistic associations with plant roots, enhancing nutrient uptake, inducing systemic defence responses, and directly suppressing pathogen growth. Endophytes within plant tissues produce antimicrobial compounds, induce systemic resistance, and compete with pathogens, thus boosting host resistance. Understanding the functional roles and mechanisms of PGPRs, AMFs, and endophytes in enhancing host resistance provides valuable insights for sustainable disease management strategies, reducing reliance on chemical pesticides, and ensuring global food security. Further research is needed to optimize the application of these beneficial microorganisms in agricultural systems.