Endophytic bacteria in a single plant host are not restricted to a single species, but comprise several gen- era and species. It is not known whether these multiple endophytic microorganisms inside the plants interact. However, it has been speculated that beneficial effects are the combined effect of activities of these microbes influencing plant productivity. It seems likely that inter- actions among endophytes takes place in planta, specifi- cally those that are depending on quorum sensing.