Chapter 23 - Plant beneficial microbes and their role in planthealth

Abstract

The three-way interaction between host, pathogen, and plant-beneficial microbes is a sequential process, which involves various steps such as recognition, signaling, and response. Beneficial microbes viz. plant growth–promoting rhizobacteria/plant growth–promoting fungi either directly restrict the entry of invading pathogens or indirectly compete with pathogenic species, which thereafter leads to the induction of systemic resistance within the plants. Generally, the presence of microbes is perceived by recognition receptors present on the host surface, and then their perception leads to the activation of various defense-related responses involving the activation of rapid defense response and regulation of hormonal signaling. Different elicitors involved in the activation of plant immunity to various stress factors are microbe-associated molecular patterns/pathogen-associated molecular patterns/damage-associated molecular patterns/nematode-associated molecular patterns. Surface structures of microbes, quorum-sensing molecules, different secondary metabolites, siderophores, various enzymes, etc., serve as elicitors (molecular patterns) of plant defense activation. The effects of beneficial microbes in the management of plant diseases are already known, but their utilization at commercial scale is still at infancy. This chapter highlights the mechanism of three-way interaction between host, pathogen, and beneficial microbes and also emphasizes on the importance of plant-beneficial microbes in the management of plant diseases as an alternative to the use of chemicals.