Interplay between endophyte and host plant in the synthesis and modification of metabolites.

Abstract The interplay between plants and microbes in their contribution of secondary metabolite synthesis is still not well understood. While plant pathogens might contribute by the synthesis of toxic compounds and the host by making antimicrobial compounds, the synthesis of secondary metabolites in the interaction of plants with endophytic organisms might be much more sophisticated. One possibility is that the plant makes antimicrobial compounds that are either sequestered or metabolized by the endophytic organisms. Alternatively, the inhabitant makes compounds that are released into the plant or environment for its own benefit. Such a compound can also be altered biochemically by the host. Finally, the two partners can contribute to one pathway by using an intermediate synthesized by one and later made to another compound by the other partner. Such examples and the implication for future research to identify the organisms mainly responsible for the biosynthetic pathways are discussed in this chapter.