Harry S. Truman College1, Biology, Chicago, IL 60640 Hope College2, Biology, Holland, MI 49423
Environmental Science
EFFECTS OF JASMONIC ACID AND AN ENDOPHYTIC FUNGUS OF PLANT RESISTANCE TO INSECT HERBIVORES , L. M. Simons1, T. Bultman*2, T. J. Sullivan2, Harry S. Truman College1, Department of Biology, Chicago, IL 60640, Hope College2, Department of Biology, Holland, MI 49422, bultmant@hope.edu
Tall fescue (Lolium arundinaceum) has been observed to have a mutualistic relationship with the fungal endophyte Neotyphodium coenophialum. Jasmonic acid and its conjugates have recently been shown to be key signaling compounds in many species. Jasmonic acid also plays a role systemically in the up-regulation of defensive compounds within the plant following an onset attack by pathogens or herbivores. The purpose of the study was to test for an interaction between the ability of Neotyphodium coenophialum to produce lolines in response to host wounding and the ability of the plant to react to exposure to methyl jasmonate. It was found that methyl jasmonate down-regulated the transcription of the lolc-2 gene in infected tall fescue, hindering the plant’s ability to defend against insect herbivores. The opposite was found in uninfected tall fescue that was exposed to methyl jasmonate where a significant reduction in insect herbivore performance was observed. These results indicate that methyl jasmonate is inducing defensive compounds in uninfected tall fescue. Methyl jasmonate has an effect in infected plants by inhibiting the transcription of lolc-2 in Neotyphodium coenophialum. Currently Neotyphodium coenophialum is being grown in culture, so that the direct effects of methyl jasmonate on the endophyte can be observed.
L. M. Simons was supported by NSF-URC grant No. 0629174 and NSF-CRUI DBI-0139035
[Abstract (DOC)]