Project Number: 6227-21310-008-38
Project Type: Specific Cooperative Agreement

Start Date: Feb 15, 2008
End Date: Feb 14, 2013

Objective:
The objectives of this cooperative research project are: 1) to produce two different populations of tall fescue (TF); 2) a method to distinguish genetically different endophytes; 3) variation in plant defense mechanisms among TF (E-, E+, NE+) populations; and 4) to analyze the biological activities of constituents and on products from E+ TF.

Approach:
KY-31 TF inoculated with 15 strains of endophyte lacking ergopeptide alkaloids will be drilled into plots. Plots will be flashed grazed by cattle, and stand survival percentage measured each fall using E- TF populations collected from pastures will be planted in small plots into BG. Plots will be grazed and evaluated for stand survival in the spring to estimate winter hardiness. A multi-locus microsatellite-based PCR procedure will be used to establish the genetic identity of isolates of NE+ strains used in the genomic research. Plants will be grown in a greenhouse in sand culture. Comparisons of analyses of E- and NE+ with and without water stress should identify gene products related to tolerance from both the plant and endophyte. Antimicrobial chitinases of TF will be identified. Broad-based genetic populations of TF (E-, E+, NE+) will be assayed for chitinase activities. Activity levels will be correlated with persistence and pest resistance observations. E- TF germplasm will be evaluated for other plant disease defense activities. Livers, intestinal, and rumenal tissues will be harvested aseptically during postmortems from rodents, cattle, and sheep. Tissues will be harvested and assayed for ergotamine disappearance from animals differing in exposure to E+ TF and sensitivity to its effects. Degradation products will be isolated and screened for bioactivities associated with fescue toxicosis, i.e., inhibition of ATPase activity and prolactin secretion.