Microbial control of root-pathogenic fungi and oomycetes

The rhizosphere is a complex and dynamic environment in which microbes
introduced to control root pathogens must establish and maintain populations of sufficient size and activity to antagonize pathogens directly or by manipulating the host plant’s own defenses. Genetic and physiological studies of rhizobacteria with the capacity to control root pathogens have given considerable insight into the microbial side of these interactions, but much remains to be learned about the physical conditions and the chemical and biological activities that take place at the root-microbe interface. This chapter focuses on advances in our understanding of the constraints to the successful introduction of microbial agents for the control of soil-borne root pathogens and the mechanisms involved in pathogen suppression. Chapters elsewhere in this volume address related topics including plant growth promotion, stress control, the activation of the plant’s own defense mechanisms by introduced microbes, and powerful new biotechnological advances available to gain insight into rhizosphere processes.