Endophyte

An endophyte is an organism that lives within a plant for at least part of its life without causing apparent disease. Endophytes are ubiquitous and have been found in nearly all plants studied to date.

However, most of these endophyte/plant relationships are not well understood; however, the type of symbiosis exhibited between plant and endophyte is often related to the reproductive mode of the endophyte. For example, vertically transmitted endophytes are asexual and transmit via fungal hyphae penetrating the host’s seeds (e.g. Neotyphodium). Evolutionary theory predicts these endophytes to evolve toward mutualism, since their reproductive fitness is intimately tied to that of their host plant. Conversely, horizontally transmitted endophytes are sexual and transmit via spores that can be spread by wind and/or insect vectors. Therefore, these endophytes can evolve a more pathogenic lifestyle since they can escape their host plant.

See also: Endosymbiont