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Article Addendum

Insect-induced gene expression at the core of volatile terpene release in Medicago truncatula

Wayra G. Navia-Giné, S. Karen Gomez, Joshua Yuan, Feng Chen and Kenneth L. Korth

The blends of induced volatiles released by higher plants in response to herbivory regularly contain terpenoids. The precursors of volatile terpenoids can be synthesized via two pathways, the mevalonate (MVA) and the methyl erythritol 4-phosphate (MEP) pathways localized in the cytosol and in plastids, respectively. Terpenes are important players in interactions between plants and herbivorous insects, by acting in both direct and indirect defenses. We recently characterized a gene encoding an (E)-β-ocimene synthase (MtEBOS) in the legume Medicago truncatula Gaertn.  Compared to undamaged plants, caterpillar-damaged M. truncatula emitted (E)-β-ocimene at an elevated level and this increase is associated with high levels of expression of MtEBOS mRNA. Exogenous treatment with jasmonic acid also increases transcript accumulation of MtEBOS. These results indicate that transcript accumulation is used as a tightly regulated mechanism to control (E)-β-ocimene emission.  The data, along with additional findings in other species, illustrate that like most plant families legumes regulate the final steps of volatile terpene biosynthesis at the level of transcript induction.

Addendum to: Navia-Giné WG, Yuan JS, Mauromoustakos A, Murphy JB, Chen F, Korth KL. Medicago truncatula (E)-β-ocimene synthase is induced by insect herbivory with corresponding increases in emission of volatile ocimene. Plant Physiol Biochem 2009; 47:416–25; PMID: 19249223; DOI: 10.1016/j.plaphy.2009.01.008.

Authors

Wayra G. Navia-Giné

Department of Plant Pathology; University of Arkansas; Fayetteville, Arkansas USA

S. Karen Gomez

Department of Plant Pathology; University of Arkansas; Fayetteville, Arkansas USA

Joshua Yuan

Department of Plant Science; University of Tennessee; Knoxville, TN USA

Feng Chen

Department of Plant Sciences; University of Tennessee; Knoxville, TN USA

Kenneth L. Korth Corresponding author: kkorth@uark.edu

Department of Plant Pathology; University of Arkansas; Fayetteville, Arkansas USA