Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: September 12, 1996
Publication Date: N/A
Interpretive Summary: Fungi that live their entire life cycle within grasses are referred to as endophytes and includes fungi such as Acremonium, Epichloe, and Balansia. The relationship between the grass and fungus is beneficial to both organisms. During the process of evolution both fungus and grass became partners dependent on a two-way exchange of chemical compounds needed for the survival of both. Thus, the fungus and grass produce defensive compounds, growth regulating compounds, compounds related to dissemination, and compounds associated with sexual and asexual reproduction. Scientists at RRC were instrumental in isolating and identifying several of these compounds, which forms the basis for this invited review. This chapter reviews the various classes of chemical compounds produced by endophytic fungi and outlines their importance to the association and in several instances indicates their potential for technological transfer to agriculture. This review presents the structure of each class of compounds and defines their role in the survival of both the fungus and grass. Understanding the chemistry of these interrelationships is important for improving and developing grasses which is a major thrust of agriculture's forage crop and turf commodity, as well as identifying other sources for novel biologically active compounds.
Technical Abstract: Endophytic fungi that live their entire life cycle within their plant host, have survived by developing a close interrelationship beneficial to both. Throughout the evolutionary processes, subsistence for both fungus and plant host became dependent on a reciprocal exchange of biochemical mechanisms and the subsequent production of compounds needed for their mutual survival; that is, production of those compounds associated with defense (the ergot alkaloids, the pyrrollizidine loline alkaloids, the pyrrolopyrazine alkaloid peramine, and to some extent the lolitrem alkaloids provide protection against herbivorous insects); production of compounds associated with growth (auxin production, indole acetic acid, indole acetamide, indole ethanol, indole glycerols, etc.); production of compounds associated with dissemination (alleochemical production, possibly the alleopthaic activities of the loline alkaloids); and the development of mechanisms associated with proliferation of the species (via sexual or asexual reproduction: Epichloe vs. Acremonium). Understanding the interrelationships with the endophyte-host plants associations and alkloid production promises to be one of our most unique natural resources for controlling and developing agriculture on numerous levels and one of the most prolific sources of novel biologically active compounds.