Geranyllinalool Synthases in Solanaceae and Other Angiosperms Constitute an Ancient Branch of Diterpene Synthases Involved in the Synthesis of Defensive Compounds. Issue 1 (22nd July 2014)

• Record Type: Journal Article
• Authors: Falara, Vasiliki; Alba, Juan M.; Kant, Merijn R.; Schuurink, Robert C.; Pichersky, Eran
• Is Part Of: Plant physiology. Volume 166:Issue 1(2014)
• Page Start: 428
• Page End: 441
• Publication Date: 2014-07-22
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1104/pp.114.243246
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract : The genes encoding geranyllinalool synthases in Solanaceae represent an ancient branch of the terpene synthase gene family that likely diverged from the rest of the family prior to the split between the gymnosperm and angiosperm lineages . Abstract: Many angiosperm plants, including basal dicots, eudicots, and monocots, emit ( E, E )-4, 8, 12-trimethyltrideca-1, 3, 7, 11-tetraene, which is derived from geranyllinalool, in response to biotic challenge. An Arabidopsis ( Arabidopsis thaliana ) geranyllinalool synthase (GLS ) belonging to the e/f clade of the terpene synthase (TPS ) family and two Fabaceae GLS s that belong to the TPS -g clade have been reported, making it unclear which is the main route to geranyllinalool in plants. We characterized a tomato ( Solanum lycopersicum ) TPS -e/f gene, TPS46, encoding GLS ( SlGLS ) and its homolog ( NaGLS ) from Nicotiana attenuata . The K m value of SlGLS for geranylgeranyl diphosphate was 18.7 µm, with a turnover rate value of 6.85 s –1 . In leaves and flowers of N. attenuata, which constitutively synthesize 17-hydroxygeranyllinalool glycosides, NaGLS is expressed constitutively, but the gene can be induced in leaves with methyl jasmonate. In tomato, SlGLS is not expressed in any tissue under normal growth but is induced in leaves by alamethicin and methyl jasmonate treatments. SlGLS, NaGLS, AtGLSs, and several other GLS s characterized only in vitro come from four different eudicot families and constitute a separate branch of the TPS -e/f clade that diverged from kaurene synthases, also in the TPS -e/f clade, before the gymnosperm-angiosperm split. The early divergence of this branch and the GLS activity of genes in this branch in diverse eudicot families suggest that GLS activity encoded by these genes predates the angiosperm-gymnosperm split. However, although a TPS sequence belonging to this GLS lineage was recently reported from a basal dicot, no representative sequences have yet been found in monocot or nonangiospermous plants.