Metabolic, Genomic, and Biochemical Analyses of Glandular Trichomes from the Wild Tomato SpeciesLycopersicon hirsutumIdentify a Key Enzyme in the Biosynthesis of Methylketones
Open Access
- 1 April 2005
- journal article
- Published by Oxford University Press (OUP) in Plant Cell
- Vol. 17 (4), 1252-1267
- https://doi.org/10.1105/tpc.104.029736
Abstract
Medium-length methylketones (C7-C15) are highly effective in protecting plants from numerous pests. We used a biochemical genomics approach to elucidate the pathway leading to synthesis of methylketones in the glandular trichomes of the wild tomato Lycopersicon hirsutum f glabratum (accession PI126449). A comparison of gland EST databases from accession PI126449 and a second L. hirsutum accession, LA1777, whose glands do not contain methylketones, showed that the expression of genes for fatty acid biosynthesis is elevated in PI126449 glands, suggesting de novo biosynthesis of methylketones. A cDNA abundant in the PI126449 gland EST database but rare in the LA1777 database was similar in sequence to plant esterases. This cDNA, designated Methylketone Synthase 1 (MKS1), was expressed in Escherichia coli and the purified protein used to catalyze in vitro reactions in which C12, C14, and C16 β-ketoacyl–acyl-carrier-proteins (intermediates in fatty acid biosynthesis) were hydrolyzed and decarboxylated to give C11, C13, and C15 methylketones, respectively. Although MKS1 does not contain a classical transit peptide, in vitro import assays showed that it was targeted to the stroma of plastids, where fatty acid biosynthesis occurs. Levels of MKS1 transcript, protein, and enzymatic activity were correlated with levels of methylketones and gland density in a variety of tomato accessions and in different plant organs.Keywords
This publication has 60 references indexed in Scilit:
- ARC6 is a J-domain plastid division protein and an evolutionary descendant of the cyanobacterial cell division protein Ftn2Plant Cell, 2003
- Ketosynthases in the Initiation and Elongation Modules of Aromatic Polyketide Synthases Have Orthogonal Acyl Carrier Protein SpecificityBiochemistry, 2003
- Tomato, Pests, Parasitoids, and Predators: Tritrophic Interactions Involving the GenusLycopersiconAnnual Review of Entomology, 2003
- Tree View: An application to display phylogenetic trees on personal computersBioinformatics, 1996
- Envelope membrane proteins that interact with chloroplastic precursor proteins.Plant Cell, 1994
- Inhibition ofCampoletis sonorensis parasitism ofHeliothis zea and of parasitoid development by 2-tridecanone-mediated insect resistance of wild tomatoJournal of Chemical Ecology, 1989
- Activity of volatile compounds in glandular trichomes ofLycopersicon species against two insect herbivoresJournal of Chemical Ecology, 1987
- Some unsaponifiable constituents of the deodorisation distillates of vegetable oilsJournal of the Society of Chemical Industry, 1947
- Ueber das Ceylon-ZimmtölJournal für Praktische Chemie, 1902
- XXXII.—On the essential oil of lime leaves (citrus limetta). Preliminary noticeJournal of the Chemical Society, Transactions, 1886