Endophyes are microbes that exist within plant tissues.  These presence of these organisms are often not noticed because the organisms do not present any outward symptoms.  They can be found locally in specific tissues, or spread throughout tissues.  Some endophytes have been identified that have significant beneficial impacts to their plant host.  An endophytic fungus in tall fescue produces chemicals that help to reduce damage from insects and heat stress.  Endophytes in other systems ward off slugs, fix nitrogen, and improve plant growth.  Chemicals produced by several medicinal plants have been shown to be produced by endophytic fungi-when fungicides are applied, the plant loses its medicinal properties.  Researchers  recently published results of research conducted on an endophyte on wheat growth, suppression of Fusarium head blight (FHB), and associated mycotoxin development.  Their initial results showed that the endophyte could significantly reduce disease severity and incidence and reduce DON concentrations compared to uninoculated controls (reductions of 70% or more were noted in both instances]). The endophyte also increased above ground biomass, and yield.  Effects were consistent at different fertilization levels.  These initial results offer promise to a potentially systemic endophytic biological control for suppression of FHB.

The article can be found here

Source:  Rabiey, M. and M.W. Shaw, Piriformospora indica reduces Fusarium head blight disease severity and mycotoxin DON contamination in wheat under UK weather conditions. Plant Pathology, 2015: p. n/a-n/a.