Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/2002
Publication Date: 5/13/2002
Citation: Glenn, A.E. 2002. FUNGAL ENDOPHYTES OF GRASSES: SYMBIOTIC INTERACTIONS AT THEIR BEST.....AND WORST. Department of Plant Pathology Annual Retreat. May 13 - 14, 2002. Amicolola Falls, GA. Interpretive Summary: Abstract - no interpretive summary required. Invited presentation for the Department of Plant Pathology Annual Retreat, May 13-14, 2002, Amicolola Falls, Georgia.
Technical Abstract: Fungi that grow within plant tissues for all or part of their life cycle without causing any disease symptoms are referred to as endophytes. This form of symbiotic interaction has attracted much attention over the past 25 years, in large part due to discoveries made within the Toxicology and Mycotoxin Research Unit. Endophytic fungi within agronomically important hosts such as tall fescue and corn are now known to produce metabolites that are detrimental to animal health. These mycotoxins have significant impact on the health and overall economic value of livestock that is grazed upon infected fescue or fed contaminated corn. As part of a larger research program focusing on the capacity of fungi to infect and endophytically colonize corn, I have examined an apparent pathogenicity factor produced by the fungus Fusarium verticillioides that impacts corn seedlings. Genetic analysis of field isolates indicated a single locus segregates for ability to cause disease. Strains carrying the non-pathogenic allele did not cause any disease symptoms, yet still infected and endophytically colonized the corn seedlings. Mutant strains that were greatly attenuated in their ability to infect seedlings nonetheless caused severe symptoms, suggesting the pathogenicity factor may be a translocated phytotoxin. Fumonisin B1 (FB1) production was assessed among the parental and progeny strains and was also found to segregate as a single locus. Linkage between pathogenicity and fumonisin production was supported since only the pathogenic strains produced FB1. Further experiments are underway to better quantify this linkage, examine the molecular nature of the mutation resulting in fumonisin non-production, and also examine the dynamics of FB1 production in soils.