2013 Annual Report
1a.Objectives (from AD-416):
To characterize and compare metabolite profiles in tall fescue endophyte-infected and endophyte-free clone pairs.
1b.Approach (from AD-416):
Tall fescue, KY31, containing the wild-type fungal endophyte (Neotyphodium coenophialum) strain has been used to generate endophyte-free lines, constituting of a genetically identical plant background with and without the endophyte. These clone pairs provide a tool to characterize and compare gene expression, metabolite profiles and phenotypic responses, in an identical genetic background, thus allows comparisons based solely on the presence or absence of the endophyte.
The cloned pairs of tall fescue have been used initially in a project to determine the variation found in the endophyte that infects KY31. The Samuel Roberts Noble Foundation have included the cloned pairs (supplied by ARS Scientist in Forage-Animal Production Research Unit at Lexington, KY) as well as seed that these clone pairs have originated from (supplied by University of Kentucky Cooperator). At least 2 copies of each line is maintained in The Noble Foundation greenhouses and they are regularly (every 6 months) screened for endophyte infection using a polymerase chain reaction based screen. In all the screens, the endophyte-free (E-) and endophyte-infected (E+) lines have always remained true to form. However, some plants died following the initial transport of the plants, thus The Noble Foundation now maintains 11 E+/E- clone pairs. Each line has been tested for the presence of two simple sequence repeat markers (B10 and B11, Moon et al, 1999) that show variation within and across Neotyphodium (N.) coenophialum strains. A series of Ribonucleic acid (RNA)-seq datasets with samples that include E+ and E- clonal material (clones 27 and 52, representing different common toxic endophyte strains) provided by ARS Scientist in Forage-Animal Production Research Unit at Lexington, KY, have been done. A number of libraries (including biological replications) have been generated with unique tags and pooled. These samples have been sequenced using the Illumin Hi-Seq protocol and RNA-seq data is being evaluated. The data has been mapped to the Epichloë festucae gene models and will be made accessible as an interactive web server for the N. coenophialum gene expression atlas. The clone pairs have been screened for the presence of ergot and peramine alkaloids and, while minor variation was observed, all the plants containing the common toxic endophyte have the alkaloids present. This report serves as the final report for this project as future work will be conducted on plants containing non-toxic, or novel, endophytes.