ABSTRACT
In writing this chapter we had two objectives. The first was to provide a brief overview of the results regarding the distribution and metabolic state of endophyte mycelium within perennial rye grass (Lolium perenne) tillers which we have obtained using the GUS reporter gene system. The second was to share our view of the cellular biology of grass endophytes in planta and the evolution of some aspects ofthis biology-a view that has emerged from the use of the GUS system, not only from the results obtained but in some cases also by problems with the method that we encountered.
