Bacterial Antagonists against Plant Pathogens: Mode of Actions

Plant pathogens pose a significant threat to global crop production, responsible for 20-40% of crop losses worldwide due to pre- and post-harvest diseases. Chemical control methods have long been used in agriculture to combat these losses. However, growing concerns over the environmental and health impacts of chemical pesticides have driven interest in biological control as a sustainable and effective alternative. Biological control, particularly through bacterial antagonists (BAs) offers a promising solution for integrated plant disease management and has the potential to enhance crop yields in an environmentally friendly manner. Bacterial antagonists inhibit the growth of plant pathogens through various mechanisms such as direct competition (for nutrients and space, antibiosis, production of antimicrobial compounds) and indirect competition (induction of plant defense responses and plant growth). Many of these beneficial bacteria are naturally occurring members of the microbial community, found ubiquitously in the environment. This review discusses the primary modes of action of bacterial antagonists, detailing the mechanisms and molecules involved in their biocontrol activity.