Endophyte

From Wikipedia, the free encyclopedia

This article does not cite any references or sources. (March 2008)
Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.

An endophyte is an endosymbiont, often a bacterium or fungus, that lives within a plant for at least part of its life without causing apparent disease. Endophytes are ubiquitous and have been found in all the species of plants studied to date; however, most of these endophyte/plant relationships are not well understood.

Endophytes may be transmitted either vertically (directly from parent to offspring) or horizontally (from individual to unrelated individual). Vertically transmitted fungal endophytes are asexual and transmit via fungal hyphae penetrating the host’s seeds (e.g. Neotyphodium). Since their reproductive fitness is intimately tied to that of their host plant, these fungi are often mutualistic. Conversely, horizontally transmitted fungal endophytes are sexual and transmit via spores that can be spread by wind and/or insect vectors. Since they spread in a similar way to pathogens, horizontally transmitted endophytes are often closely related to pathogenic fungi.

Some endophytes can colonize multiple species of plants.

Endophytes may benefit host plants by preventing pathogenic organisms from colonizing them. Extensive colonization of the plant tissue by endophytes creates a "barrier effect", where the local endophytes outcompete and prevent pathogenic organisms from taking hold. Endophytes may also utilize chemicals which inhibit the growth of competitors, including pathogenic organisms.

Some endophytes can be cultured from their host plant in an appropriate growth medium.

Endophytes sometimes not only work to the advantage of their traditional host plant but can be used to combat pathogens and even cancers in animals including humans. One notable endophyte with medicinal benefits to humans produces taxol, and is found in the Pacific Yew tree. It is speculated that there may be many thousands of endophytes useful to mankind but since there are few scientists working in this field, and since forests and areas of biodiversity are rapidly being destroyed, many useful endophytes for curing disease might be permanently lost for medicinal use before they are discovered.