Mycorrhizal fungi and other root endophytes as biocontrol agents against root pathogens

Abstract

In nature, production of disease-free plants with enhanced yield and compounds of therapeutic value can be mediated through rhizospheric microorganisms. There are increasing environmental concerns over the widespread use of biocontrol measures in general, and alternatively, more sustainable methods of disease control are now being sought. Plant diseases caused by root pathogens need to be controlled in order to maintain the quality and abundance of food, feed and fiber, the prime necessities of life. Different approaches are used for prevention and control of these root pathogens. Among these alternatives are those referred to as biological control; the most obvious and apparently biological control is a potent means of reducing the damage caused by plant pathogens. The potential agents for biocontrol activity are rhizosphere-competent fungi and bacteria which, in addition to their antagonistic activity, are capable of inducing growth responses by either controlling minor pathogens or by producing growth-stimulating factors. A variety of biological controls are available for use, but further development and effective adoption requires a greater understanding of the complex interactions among plants, people, and the environment. This article emphasizes: (1) information about mycorrhiza and root endophytes, (2) various definitions and key mechanisms of biocontrol, and (3) the relationships between microbial diversity and biological control.