| Abstract Detail
Secondary Metabolism Navia-Gine, Wayra [1], Yuan, Joshua S. [2], Chen, Feng [2], Korth, Kenneth L. [3]. Regulation of an insect-induced E-(beta)-ocimene synthase and other terpene synthases of Medicago truncatula. The barrel medic, Medicago truncatula, is a legume widely used as a model for the study of plant-symbiont interactions. Virtually all plants, including M. truncatula, are able to recognize attack by insects and release volatile organic compounds (VOCs) in response. Thus, M. truncatula can also serve as a useful tool for the study of legume responses to insect damage. Among the most abundant and varied classes of induced VOCs are the terpenes. Four putative terpene synthases genes from M. truncatula were shown to be induced at the transcript level by insect herbivory, insect oral factors, methyl jasmonate, and mechanical wounding. A full-length cDNA sequence of a putative monterpene synthase, MtTps4, was cloned into an E. coli expression vector. The protein encoded by MtTps4 was shown to have ocimene synthase activity following addition of labeled substrate, geranyl diphosphate (GPP), to the E. coli-expressed protein. Ocimene is a 10-carbon monoterpene commonly found among volatile compounds emitted by insect-damaged plants. Additional characterization of MtTps4 expression includes measures of transcripts in various plant tissues and in response to ethylene treatments. A putative sesquiterpene synthase, MtTps1, is also being characterized by in vivo protein expression and measurement of transcript responses using real-time RT-PCR. Transcripts for MtTps1 accumulate rapidly and to high levels in response to chewing insect herbivory. This work should lead to better understanding of the regulation of terpenoid biosynthesis in M. truncatula, and might identify enzymes directly responsible for the production of key terpenes that play a role in insect defenses.
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Related Links:
korth Lab- University of Arkansas
1 - University of Arkansas, Plant Pathology, 217 Plant Science Bldg, Fayetteville, AR, 72701, United States
2 - University of Tennessee, Plant Sciences
3 - University of Arkansas, Plant Pathology
Keywords:
terpenoid
wound.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P20015
Abstract ID:292 |
