|White, Jr, James|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 9/30/1998
Publication Date: N/A
Interpretive Summary: Most grasses are associated with fungi that alive within the foliage parts. These fungi are referred to as endophytes. Most grasses are associated with these fungi and the association benefits both grass and fungus. This type association is referred to as mutualistic. Indeed, the presence of the fungus confers several ecological benefits such as increased growth under grazing pressures, drought tolerance, insect and disease resistance, reduced feeding by animals, as well as competition with other grasses. The grass provides nutrients to the fungus, as well as protection and a habit. However, the means by which the nutritional aspects of this association is accomplished is unknown. This paper presents our concepts on the physiology, mainly nutritional, its impact on the need for the association and the resulting evolution of this group of endophytes. Book Chapter in MICROBIAL ENDPOPHYTES, C.W. Bacon and J.F. White, Jr., Marcel Dekker, Inc., New York, NY.
Technical Abstract: In summary, the Clavicipitaceae consists of fungi that produce three generalized morphological structures across which physiological interactions occur: 1. Some fungi are ovarian replacement diseases, and the only interaction with the grass is that at the base of the grass ovary, and this infection is intracellular and intercellular; examples of these are represented by species of Claviceps. These species are in the tribe Clavicipiteae, are not endophytically associated with its host foliage cells and are not a part of this discussion, although references will be made to them for the sake of comparison. 2. Other grass symbionts are epibiotic species, and all fungi in this group belong to the tribe Balansiae, which are characterized as having simple stromata that are located on stems, florets, or leaves of hosts. The hyphae are not intercellular but are epicuticular, and very seldom is there deep penetration into the hosts, below the epidermal cells. 3. The final group include strictly endophytic species, which include those fungi that belong to the tribe Balansiae and produce stromata that are located on leaves, stems and florets of hosts; the hyphae are intercellular and only rarely epicuticular, except at points of egress.