GENETIC EXPRESSION PROFILES OF THE TALL FESCUE-ENDOPHYTE SYMBIOSIS RELATING TO DROUGHT STRESS TOLERANCE
Forage-Animal Production Research
2011 Annual Report
1a.Objectives (from AD-416)
To characterize genetic expression profiles of drought stressed tall fescue containing novel endophytes strains and verify gene expression profiles of selected genes.
1b.Approach (from AD-416)
Tall fescue, KY31, containing six novel endophyte strains, plus the endophyte-free and KY31 with wild-type endophyte will be evaluated under different drought stress regimes to characterize differences in gene expression profiles and correlate these with phenotypic response to the treatments. The KY31 lines differ in their response to drought stress and the goal is to compare gene expression levels and identify putative genes that are over- or under-expressed in response to the stress experiments that correlate with increased drought tolerance. ARS is developing an expression profiling tool for tall fescue for analysis of whole genome expression comparisons. This will be used to compare expression of the different KY31 lines containing the different endophyte strains to determine the effect of gene expression, using real time PCR techniques, in drought tolerance response. Three replications comparing non-stressed (beginning of the experiment) and three replications of stressed material for each of the lines will be evaluated. RNA will be isolated from pseudostems of each line for each treatment for analysis.
We have generated Endophyte-infected (E+) and Endophyte-fre (E-) clone pairs for each of the seedlots above (number of clone pairs in parentheses): [KY4 (11); KY15 (6); KY16 (8); KY17 (13); KY18 (6); KY19 (5); KY20 (8); KY28 (10); KY32 (14)]. Verification of the absence of ergot alkaloids has been done on all clone pairs. Additional alkaloids, namely N-acetyl loline, N-formyl loline and peramine have been done on a number of these identifying varying levels of these alkaloids in these clone pairs. Plants derived from one clone pair originally from KY16 and KY19 have been increased and subjected to drought stress experiments and samples collected over a five day period for metabolite and transcriptome analysis. This project was monitored with face-to-face meetings, teleconferences, emails, and involvement in the research.