Exploration of microbial stimulants for induction of systemic resistance in plant disease management

Plants are exposed to different environmental stresses (biotic or abiotic) in their habitats, these stresses often result in several diseases and decline in crop production which are major concerns to crop producers and scientists. Habitat-imposed biotic stress is one of the most common problems of crop production. The use of chemical-based pesticides has been widely reported to control plant diseases but the residual effects of excessive application of pesticides necessitates the use of biological control agents known to play important safety roles in plant disease management. Symbiotic associations between diverse microorganisms and plant roots have also been proven to have enormous impacts on their respective growths and survival; induced systemic resistance (ISR) is part of the mechanism through which plant-growth-promoting bacteria and fungi stimulate plant growth and resistance to pathogens. Many of these microorganisms act as stimulants which can be exploited for boosting nutrient uptake, pest control and to protect crops from environmental stresses for better growth. This review focuses on the plant diseases, microbial stimulants and their mechanisms as nutrient enhancers in crop production as well as their potentials in biological control of plant diseases through ISR.