Microbial-derived inducers of plant immunity: recent advances and future prospects

Main conclusion This review provides a comprehensive overview of microbial-derived inducers of disease resistance in plants, elucidates their mode of action, and offers prospects for their practical application. Plants are constantly facing various pests and pathogens such as fungi, bacteria, viruses, insects, nematodes, etc., leading to an important loss in crop productivity. While conventional pesticides are effective in eliminating these pathogens, their use poses serious environmental and health risks. Plants can combat these pathogens by activating different facets of their innate defense mechanisms. In this context, several microbial-derived inducers enable plants to resist various pathogens by rapidly and intensely activating host-defense reactions after invader recognition. These inducers include oligosaccharides, lipids, peptides, and proteins, which can activate the plant immune system. They trigger various signaling pathways that commonly induce reactive oxygen species (ROS) generation, phytoalexin production, and pathogenesis-related (PR) proteins biosynthesis. This review outlines various microbial inducers that boost plant disease resistance, elucidating their basic modes of action. Moreover, it engages with the latest methodologies, and prospects for developing and applying microbial-derived inducers.