The Maize Geneterpene synthase 1Encodes a Sesquiterpene Synthase Catalyzing the Formation of (E)-β-Farnesene, (E)-Nerolidol, and (E,E)-Farnesol after Herbivore Damage

Abstract

Maize (Zea mays) emits a mixture of volatile compounds upon attack by the Egyptian cotton leafworm (Spodoptera littoralis). These substances, primarily mono-and sesquiterpenes, are used by parasitic wasps to locate the lepidopteran larvae, which are their natural hosts. This interaction among plant, lepidopteran larvae, and hymenopteran parasitoids benefits the plant and has been termed indirect defense. The committed step in the biosynthesis of the different skeletal types of mono-and sesquiterpenes is catalyzed by terpene synthases, a class of enzymes that forms a large variety of mono-and sesquiterpene products from prenyl diphosphate precursors. We isolated a terpene synthase gene, terpene synthase 1 (tps1), from maize that exhibits only a low degree of sequence identity to previously identified terpene synthases. Upon expression in a bacterial system, the encoded enzyme produced the acyclic sesquiterpenes, (E)-␤-farnesene, (E,E)-farnesol, and (3R)-(E)-nerolidol, the last an intermediate in the formation of (3E)-4,8-dimethyl-1,3,7-nonatriene. Both (E)-␤-farnesene and (3E)-4,8-dimethyl-1,3,7-nonatriene are prominent compounds of the maize volatile blend that is emitted after herbivore damage. The biochemical characteristics of the encoded enzyme are similar to those of terpene synthases from both gymnosperms and dicotyledonous angiosperms, suggesting that catalysis involves a similar electrophilic reaction mechanism. The transcript level of tps1 in the maize cv B73 was elevated after herbivory, mechanical damage, and treatment with elicitors. In contrast, the increase in the transcript level of the tps1 gene or gene homolog in the maize cv Delprim after herbivory was less pronounced, suggesting that the regulation of terpene synthase expression may vary among maize varieties.

The products of a single maize sesquiterpene synthase form a volatile defense signal that attracts natural enemies of maize herbivores

“…This general attraction may have partially masked the attractive effect of the TPS10 products. Other herbivore-induced volatiles of importance to tritrophic interactions might be sesquiterpene alcohols, homoterpenes (21,22), oxylipins, and indole (23). The attraction of the predatory mite Phytoseiulus persimilis to the sesquiterpene alcohol (3S)-nerolidol was recently demonstrated with transgenic Arabidopsis overexpressing a strawberry nerolidol synthase (12).…”

The Role of Indole and Other Shikimic Acid Derived Maize Volatiles in the Attraction of Two Parasitic Wasps

“…In maize plants, the mechanisms of biosynthesis, induction, and release of HIPVs are well characterized Frey et al, 2000;Shen et al, 2000;Schnee et al, 2002;Gouinguené et al, 2003;Schmelz et al, 2003a,b,c;Köllner et al, 2004;Lawrence and Novak, 2004;Ruther and Kleier, 2005), and the ecological significance of these compounds in tritrophic signaling has been demonstrated in laboratory and field experiments (Turlings et al, 1990;Bernasconi et al, 1998;Hoballah and Turlings, 2001;Fritzsche Hoballah et al, 2002;Rasmann et al, 2005). In particular, the role of green leaf volatiles and terpenoids in attracting natural enemies of the herbivores has been investigated in various experiments (D'Alessandro and Turlings, 2005;Hoballah and Turlings, 2005).…”

Rational Conversion of Substrate and Product Specificity in a Salvia Monoterpene Synthase: Structural Insights into the Evolution of Terpene Synthase Function

“…With very few exceptions, monoterpene synthases use GPP as a substrate, and only a few have been reported to be able to also use the five-carbon-longer FPP, thus catalyzing the formation of sesquiterpenes (Schnee et al, 2002;Aharoni et al, 2004). Sf-CinS1 does not make sesquiterpenes when presented with FPP as substrate.…”