Toward plant defense mechanisms against root pathogens

Abstract

As we consider the importance of the plant microbiome for sustainable agriculture,we note that some of these organisms are beneficial to plants, others arecommensal, and the third category includes pathogens. Root pathogens, such asFusarium oxysporum, are of particular interest as these can be controlled byeffective plant defense mechanisms or by biocontrol microbes. This chapterreviews recent findings of plant defense mechanisms against root pathogens.This process can be greatly assisted by microbes that prime the plant, leading toinduced systemic resistance. These microbes prepare the plant to mount a fasterand stronger response against root pathogens at a very low energetic cost to theplant. New strategies to develop resistance come from the knowledge that agriculturallyimportant root pathogens often hijack the wrong defense pathway inplants. An interesting emerging area is the plant defense mechanism that leads tothe production of root exudates which can result in the recruitment of beneficialmicrobes that assist the plant in developing resistance. Future work may focus onthe selection of plants whose defense responses against pathogens may be betterassisted by agriculturally important beneficial microbes.