MODIFICATION AND USES OF ENDOPHYTE-ENHANCED TURFGRASSES - A ROLE FOR MOLECULAR TECHNOLOGY

Over the past decade, the significance of symbiotic fungal endophytes in turfgrasses was established as having the potential for supplementi ng the genetics of turfgrass improvement since endophyte-infected gras ses frequently show enhanced performance. Endophyte-enhanced traits in clude insect and mammalian deterrence to herbivory, and often increase d tolerance of drought and other abiotic stresses. However, not all en dophytes are suited for use in enhancing grass performance, and only t hose fungi that are symptomless endophytes of grasses are currently be ing used. The endophytes that are of the major focus for current use i nclude species of Neotyphodium (=Acremonium), e.g., N. coenophialum, N . lolii, and other species of Neotyphodium. The Neotyphodium endophyte s do not reproduce sexually, and only produce conidia under laboratory culture, suggesting that they should be genetically stable. These end ophytes can be removed from the host, transformed by molecular technol ogy, and reinserted into the host. However, these fungi have other mea ns for genetic variation, which might include chromosome polymorphisms , altered chromosome structures, and loss of nonessential chromosomes. Thus, the genetics related to ani endophyte-enhanced trait of that tu rfgrass might not be stable. However, the potential for genetic engine ering of the endophytes is growing nearer with recent application of D NA mediated techniques. Furthermore, genetic engineering or other appr oaches may soon lead to endophyte-grass associations that have further enhanced fitness or are more benign to wildlife. Before such genetica lly modified systems are marketed, particular attention and extensive field tests should be applied to ensure that they retain their benefic ial characteristics and have truly acquired their intended improvement s. Continued research into the biochemical and genetics basis of endop hyte-enhanced traits should eventually identify genes that ultimately can be use for the production of transgenic grasses.