Fungal endophytes: potential biocontrol agents in agriculture

Endophytic fungi are generally recognized for their close, asymptomatic association with the internal tissues of all higher plants. There is growing interest in the symbiotic relationship between these fungi and their plant hosts due to benefits the relationship provides to the plant in areas such as development and defense. Secondary metabolites produced by endophytic fungi are of potential interest as factors in the regulation of plant communities and the herbivores that consume them. The secondary metabolites produced by endophytic fungi have been identified as sources of bioactive compounds useful in the pharmaceutical, medical and agriculture industries. Some metabolites exhibit pesticidal activities that may be effective as biocontrol agents against various agricultural pathogens. These metabolites also contribute in plant fitness by improving their adaptivity to biotic and abiotic stresses and promoting defense mechanisms. Reports on the identification of endophytic fungi and their secondary metabolites are rapidly increasing. There are variety of bioactive compounds derived from fungal endophytes, available commercially to farmers for use in pest control. The role of fungal metabolites in plant-pathogen and plant-insect interactions is receiving increased attention because of their potential use in pest control; however, the physiology and regulation of the plant–endophyte interaction requires more research. Therefore, future studies should focus on understanding the ecology of endophytic fungi, their role in plant interactions with other microbes, and their potential as biocontrol agents against pathogenic. This chapter sets out to present general biological characteristics of fungal endophytes, their diversity, their production of secondary metabolites inside host plants, and their role as biocontrol agents. The interaction between fungal endophytes and plant pathogens is also discussed in order to understand their role in protection of plants from various pathogens. Examples of bioactive compounds isolated from fungal endophytes with potent biocontrol activity are also discussed in this chapter.