|BOURGUIGNON, MARIE - University Of Kentucky
|NELSON, JIM - University Of Kentucky
|CARLISLE, ELIZABETH - University Of Kentucky
|JI, HUIHUA - University Of Kentucky
|PHILLIPS, TIM - University Of Kentucky
|MCCULLEY, REBECCA - University Of Kentucky
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2015
Publication Date: 8/16/2015
Citation: Bourguignon, M., Nelson, J.A., Carlisle, E., Ji, H., Dinkins, R.D., Phillips, T.D., McCulley, R.L. 2015. Ecophysiological responses of tall fescue genotypes to fungal endophyte infection and elevated temperature and precipitation. Crop Science. doi: 10.2135/cropsci2015.01.0020.
Interpretive Summary: Tall fescue plants symbiotic with the endophytic fungus, Epichloe coenophiala , (E+), have been shown to have better survivability and persistence than plants lacking the endophyte (E-). To understand more about the grass-endophyte interactions and how endophyte affects the host plant physiology under different environmental conditions, we analyzed physiological responses of four endophyte-infected (E+) and endophyte-free (E-) tall fescue clone pairs under elevated temperature and increased precipitation during the growing season. Often, E+ individuals performed better than E-, although in contrasting ways depending on the fescue and endophyte genotype. Overall, this study suggests that choice of plant and endophyte genetic material, especially when utilizing some of the new non-toxic endophyte strains, will be important in determining the productivity and resilience of tall fescue pastures under different climate conditions.
Technical Abstract: Tall fescue (Schedonorus arundinaceus) can form a symbiosis with the fungal endophyte, Epichloë coenophiala, whose presence can benefit the plant, depending on plant and fungal genetics and prevailing environmental conditions. Despite this symbiosis having agricultural, economic and ecological importance, relatively little is known regarding its response to predicted climate change. We quantified ecophysiological responses of four tall fescue genetic clone pairs [where each pair consisted of one endophyte-infected (E+) and one endophyte-free (E-) clone] to climate change factors of elevated temperature and increased growing season precipitation. We found significant host genotype control in E- individual responses to the climate treatments. Endophyte infection minimized fescue genotype response differences in the more mesic treatments, but elevated temperature magnified symbiotic differentiation. More endophyte effects were observed in the fall following the unusually dry summer and in the elevated temperature treatment. Toxic ergot alkaloid concentrations increased in E+ individuals exposed to climate change treatments, particularly in the fall, but the strength of the response varied across symbiotic genotypes. Overall, this study suggests that choice of plant and endophyte genetic material will be important in determining the productivity, toxicity and resilience of tall fescue pastures under future climate conditions.