farnesyl-pyrophosphate and beta-farnesene

Sesquiterpenes are characteristic components and important quality criterions for agarwood. Although sesquiterpenes are well-known to be biosynthesized by sesquiterpene synthases (TPSs), to date, only a few TPS genes involved in agarwood formation have been reported. Here, two new TPS genes, namely,

Topics: Escherichia coli; Nitric Oxide Synthase; Sesquiterpenes; Thymelaeaceae

Farnesol, derived from farnesyl pyrophosphate in the sterols biosynthetic pathway, is a molecule with three unsaturations and four possible isomers.. The study involved the addition of exogenous. Exogenously added. The findings collectively offer the first insights into the mechanism of action of farnesol on

Topics: Candida albicans; Farnesol; Leishmania; Leishmania mexicana; Sterols

Hedychium coronarium, a perennial herb belonging to the family Zingiberaceae, is cultivated as a garden plant or cut flower as well as for medicine and aromatic oil. Its flowers emit a fresh and inviting scent, which is mainly because of monoterpenes present in the profile of the floral volatiles. However, fragrance produced as a result of monoterpenes has not been well studied. In the present study, two novel terpene synthase (TPS) genes (HcTPS7 and HcTPS8) were isolated to study the biosynthesis of monoterpenes in H. coronarium. In vitro characterization showed that the recombinant HcTPS7 was capable of generating sabinene as its main product, in addition to nine sub-products from geranyl diphosphate (GPP). Recombinant HcTPS8 almost specifically catalyzed the formation of linalool from GPP, while it converted farnesyl diphosphate (FPP) to α-bergamotene, cis-α-bisabolene, β-farnesene and other ten sesquiterpenes. Subcellular localization experiments revealed that HcTPS7 and HcTPS8 were located in plastids. Real-time PCR analyses showed that HcTPS7 and HcTPS8 genes were highly expressed in petals and sepals, but were almost undetectable in vegetative organs. The changes of their expression levels in petals were positively correlated with the emission patterns of sabinene and linalool, respectively, during flower development. The results indicated that HcTPS7 and HcTPS8 were involved in the biosynthesis of sabinene and linalool in H. coronarium flowers. Results on these two TPSs first characterized from H. coronarium provide new insights into molecular mechanisms of terpene biosynthesis in this species and also lay the basis for biotechnological modification of floral scent profile in Hedychium.

Topics: Acyclic Monoterpenes; Base Sequence; Bicyclic Monoterpenes; Bridged Bicyclo Compounds; Flowers; Gene Expression; Gene Expression Regulation, Plant; Intramolecular Lyases; Molecular Sequence Data; Monoterpenes; Plant Proteins; Polyisoprenyl Phosphates; Sequence Analysis, DNA; Sesquiterpenes; Zingiberaceae

The reaction mechanisms of (E)-β-farnesene synthase (EBFS) and isoprene synthase (ISPS), enzymes that catalyze a formal regiospecific 1,4-conjugate elimination of hydrogen diphosphate from (E,E)-farnesyl and dimethylallyl diphosphate (FDP and DMADP) to generate the semiochemicals (E)-β-farnesene and isoprene, respectively, were probed with substrate analogs and kinetic measurements. The results support stepwise reaction mechanisms through analogous enzyme-bound allylic cationic intermediates. For EBFS, we demonstrate that the elimination reaction can proceed via the enzyme-bound intermediate trans-nerolidyl diphosphate, while for ISPS the intermediacy of 2-methylbut-3-enyl 2-diphosphate can be inferred from the product outcome when deuterated DMADPs are used as substrates. Possible implications derived from the mechanistic details of the EBFS-catalyzed reaction for the evolution of sesquiterpene synthases are discussed.

Topics: Alkyl and Aryl Transferases; Butadienes; Hemiterpenes; Mentha; Organophosphorus Compounds; Pentanes; Plant Proteins; Polyisoprenyl Phosphates; Populus; Pyrophosphatases; Recombinant Proteins; Sesquiterpenes

Plants can defend themselves against herbivores by attracting natural enemies of the herbivores. The cues for attraction are often complex mixtures of herbivore-induced plant volatiles, making it difficult to demonstrate the role of specific compounds. After herbivory by lepidopteran larvae, maize releases a mixture of volatiles that is highly attractive to females of various parasitic wasp species. We identified the terpene synthase TPS10 that forms (E)-beta-farnesene, (E)-alpha-bergamotene, and other herbivory-induced sesquiterpene hydrocarbons from the substrate farnesyl diphosphate. The corresponding gene is expressed in response to herbivore attack and is regulated at the transcript level. Overexpression of tps10 in Arabidopsis thaliana resulted in plants emitting high quantities of TPS10 sesquiterpene products identical to those released by maize. Using these transgenic Arabidopsis plants as odor sources in olfactometer assays showed that females of the parasitoid Cotesia marginiventris learn to exploit the TPS10 sesquiterpenes to locate their lepidopteran hosts after prior exposure to these volatiles in association with hosts. This dissection of the herbivore-induced volatile blend demonstrates that a single gene such as tps10 can be sufficient to mediate the indirect defense of maize against herbivore attack.

Topics: Animals; Arabidopsis Proteins; Bridged Bicyclo Compounds; DNA, Complementary; Electrophoresis, Agar Gel; Ethidium; Gene Library; Hydrocarbons; Intramolecular Lyases; Lepidoptera; Models, Chemical; Molecular Sequence Data; Monoterpenes; Nucleic Acid Hybridization; Open Reading Frames; Plants, Genetically Modified; Polyisoprenyl Phosphates; Polymerase Chain Reaction; RNA; RNA, Messenger; Sesquiterpenes; Smell; Time Factors; Transgenes; Zea mays

A mutant of Aristolochene Synthase (AS), in which Tyr 92 was replaced by Val, produced the alicyclic beta-(E)-farnesene as the major product, indicating that cyclisation of FPP is controlled by Tyr 92 in AS.

Topics: Amino Acid Substitution; Cyclization; Gas Chromatography-Mass Spectrometry; Isomerases; Mutagenesis, Site-Directed; Polyisoprenyl Phosphates; Sesquiterpenes; Tyrosine