Publications

• Characterization of a root-specific Arabidopsis terpene synthase responsible for the formation of the volatile monoterpene 1,8-cineole.

  Chen F., Ro D.K., Petri J., Gershenzon J., Bohlmann J., Pichersky E., Tholl D.

  Arabidopsis is emerging as a model system to study the biochemistry, biological functions, and evolution of plant terpene secondary metabolism. It was previously shown that the Arabidopsis genome contains over 30 genes potentially encoding terpene synthases (TPSs). Here we report the characterizat ... >> More

  Arabidopsis is emerging as a model system to study the biochemistry, biological functions, and evolution of plant terpene secondary metabolism. It was previously shown that the Arabidopsis genome contains over 30 genes potentially encoding terpene synthases (TPSs). Here we report the characterization of a monoterpene synthase encoded by two identical, closely linked genes, At3g25820 and At3g25830. Transcripts of these genes were detected almost exclusively in roots. An At3g25820/At3g25830 cDNA was expressed in Escherichia coli, and the protein thus produced was shown to catalyze the formation of 10 volatile monoterpenes from geranyl diphosphate, with 1,8-cineole predominating. This protein was therefore designated AtTPS-Cin. The purified recombinant AtTPS-Cin displayed similar biochemical properties to other known monoterpene synthases, except for a relatively low K(m) value for geranyl diphosphate of 0.2 microm. At3g25820/At3g25830 promoter activity, measured with a beta-glucuronidase (GUS) reporter gene, was primarily found in the epidermis, cortex, and stele of mature primary and lateral roots, but not in the root meristem or the elongation zone. Although the products of AtTPS-Cin were not detected by direct extraction of plant tissue, the recent report of 1,8-cineole as an Arabidopsis root volatile (Steeghs M, Bais HP, de Gouw J, Goldan P, Kuster W, Northway M, Fall R, Vivanco JM [2004] Plant Physiol 135: 47-58) suggests that the enzyme products may be released into the rhizosphere rather than accumulated. Among Arabidopsis TPSs, AtTPS-Cin is most similar to the TPS encoded by At3g25810, a closely linked gene previously shown to be exclusively expressed in flowers. At3g25810 TPS catalyzes the formation of a set of monoterpenes that is very similar to those produced by AtTPS-Cin, but its major products are myrcene and (E)-beta-ocimene, and it does not form 1,8-cineole. These data demonstrate that divergence of organ expression pattern and product specificity are ongoing processes within the Arabidopsis TPS family. << Less

  Plant Physiol. 135:1956-1966(2004) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Transcriptome mining, functional characterization, and phylogeny of a large terpene synthase gene family in spruce (Picea spp.).

  Keeling C.I., Weisshaar S., Ralph S.G., Jancsik S., Hamberger B., Dullat H.K., Bohlmann J.

  <h4>Background</h4>In conifers, terpene synthases (TPSs) of the gymnosperm-specific TPS-d subfamily form a diverse array of mono-, sesqui-, and diterpenoid compounds, which are components of the oleoresin secretions and volatile emissions. These compounds contribute to defence against herbivores a ... >> More

  <h4>Background</h4>In conifers, terpene synthases (TPSs) of the gymnosperm-specific TPS-d subfamily form a diverse array of mono-, sesqui-, and diterpenoid compounds, which are components of the oleoresin secretions and volatile emissions. These compounds contribute to defence against herbivores and pathogens and perhaps also protect against abiotic stress.<h4>Results</h4>The availability of extensive transcriptome resources in the form of expressed sequence tags (ESTs) and full-length cDNAs in several spruce (Picea) species allowed us to estimate that a conifer genome contains at least 69 unique and transcriptionally active TPS genes. This number is comparable to the number of TPSs found in any of the sequenced and well-annotated angiosperm genomes. We functionally characterized a total of 21 spruce TPSs: 12 from Sitka spruce (P. sitchensis), 5 from white spruce (P. glauca), and 4 from hybrid white spruce (P. glauca × P. engelmannii), which included 15 monoterpene synthases, 4 sesquiterpene synthases, and 2 diterpene synthases.<h4>Conclusions</h4>The functional diversity of these characterized TPSs parallels the diversity of terpenoids found in the oleoresin and volatile emissions of Sitka spruce and provides a context for understanding this chemical diversity at the molecular and mechanistic levels. The comparative characterization of Sitka spruce and Norway spruce diterpene synthases revealed the natural occurrence of TPS sequence variants between closely related spruce species, confirming a previous prediction from site-directed mutagenesis and modelling. << Less

  BMC Plant Biol. 11:43-43(2011) [PubMed] [EuropePMC]

  This publication is cited by 6 other entries.

• Functional and evolutionary relationships between terpene synthases from Australian Myrtaceae.

  Keszei A., Brubaker C.L., Carter R., Kollner T., Degenhardt J., Foley W.J.

  Myrtaceae is one of the chemically most variable and most significant essential oil yielding plant families. Despite an abundance of chemical information, very little work has focussed on the biochemistry of terpene production in these plants. We describe 70 unique partial terpene synthase transcr ... >> More

  Myrtaceae is one of the chemically most variable and most significant essential oil yielding plant families. Despite an abundance of chemical information, very little work has focussed on the biochemistry of terpene production in these plants. We describe 70 unique partial terpene synthase transcripts and eight full-length cDNA clones from 21 myrtaceous species, and compare phylogenetic relationships and leaf oil composition to reveal clades defined by common function. We provide further support for the correlation between function and phylogenetic relationships by the first functional characterisation of terpene synthases from Myrtaceae: a 1,8-cineole synthase from Eucalyptus sideroxylon and a caryophyllene synthase from Eucalyptusdives. << Less

  Phytochemistry 71:844-852(2010) [PubMed] [EuropePMC]

• Alternative termination chemistries utilized by monoterpene cyclases: chimeric analysis of bornyl diphosphate, 1,8-cineole, and sabinene synthases.

  Peters R.J., Croteau R.B.

  Monoterpene cyclization reactions are initiated by ionization and isomerization of geranyl diphosphate, and proceed, via cyclization of bound linalyl diphosphate, through a series of carbocation intermediates with ultimate termination of the multistep cascade by deprotonation or nucleophile captur ... >> More

  Monoterpene cyclization reactions are initiated by ionization and isomerization of geranyl diphosphate, and proceed, via cyclization of bound linalyl diphosphate, through a series of carbocation intermediates with ultimate termination of the multistep cascade by deprotonation or nucleophile capture. Three structurally and mechanistically related monoterpene cyclases from Salvia officinalis, (+)-sabinene synthase (deprotonation to olefin), 1,8-cineole synthase (water capture), and (+)-bornyl diphosphate synthase (diphosphate capture), were employed to explore the structural determinants of these alternative termination chemistries. Results with chimeric recombinant enzymes, constructed by reciprocally substituting regions of sabinene synthase with the corresponding sequences from bornyl diphosphate synthase or 1,8-cineole synthase, demonstrated that exchange of the C-terminal catalytic domain is sufficient to completely switch the resulting product profile. Exchange of smaller sequence elements identified a region of roughly 70 residues from 1,8-cineole synthase that, when substituted into sabinene synthase, conferred the ability to produce 1,8-cineole. A similar strategy identified a small region of bornyl diphosphate synthase important in conducting the anti-Markovnikov addition to the bornane skeleton. Observations made with these chimeric monoterpene cyclases are discussed in the context of the recently determined crystal structure for bornyl diphosphate synthase. << Less

  Arch Biochem Biophys 417:203-211(2003) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Monoterpene synthases from common sage (Salvia officinalis). cDNA isolation, characterization, and functional expression of (+)-sabinene synthase, 1,8-cineole synthase, and (+)-bornyl diphosphate synthase.

  Wise M.L., Savage T.J., Katahira E., Croteau R.

  Common sage (Salvia officinalis) produces an extremely broad range of cyclic monoterpenes bearing diverse carbon skeletons, including members of the p-menthane (1,8-cineole), pinane (alpha- and beta-pinene), thujane (isothujone), camphane (camphene), and bornane (camphor) families. An homology-bas ... >> More

  Common sage (Salvia officinalis) produces an extremely broad range of cyclic monoterpenes bearing diverse carbon skeletons, including members of the p-menthane (1,8-cineole), pinane (alpha- and beta-pinene), thujane (isothujone), camphane (camphene), and bornane (camphor) families. An homology-based polymerase chain reaction cloning strategy was developed and used to isolate the cDNAs encoding three multiproduct monoterpene synthases from this species that were functionally expressed in Escherichia coli. The heterologously expressed synthases produce (+)-bornyl diphosphate, 1, 8-cineole, and (+)-sabinene, respectively, as their major products from geranyl diphosphate. The bornyl diphosphate synthase also produces significant amounts of (+)-alpha-pinene, (+)-camphene, and (+/-)-limonene. The 1,8-cineole synthase produces significant amounts of (+)- and (-)-alpha-pinene, (+)- and (-)-beta-pinene, myrcene and (+)-sabinene, and the (+)-sabinene synthase produces significant quantities of gamma-terpinene and terpinolene. All three enzymes appear to be translated as preproteins bearing an amino-terminal plastid targeting sequence, consistent with the plastidial origin of monoterpenes in plants. Deduced sequence analysis and size exclusion chromatography indicate that the recombinant bornyl diphosphate synthase is a homodimer, whereas the other two recombinant enzymes are monomeric, consistent with the size and subunit architecture of their native enzyme counterparts. The distribution and stereochemistry of the products generated by the recombinant (+)-bornyl diphosphate synthase suggest that this enzyme might represent both (+)-bornyl diphosphate synthase and (+)-pinene synthase which were previously assumed to be distinct enzymes. << Less

  J. Biol. Chem. 273:14891-14899(1998) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.

• Biosynthesis of monoterpenes: partial purification, characterization, and mechanism of action of 1,8-cineole synthase.

  Croteau R., Alonso W.R., Koepp A.E., Johnson M.A.

  Geranyl pyrophosphate: 1,8-cineole cyclase (cineole synthase) catalyzes the conversion of geranyl pyrophosphate to the symmetrical monoterpene ether 1,8-cineole (1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane) by a process thought to involve the initial isomerization of the substrate to the tertiary al ... >> More

  Geranyl pyrophosphate: 1,8-cineole cyclase (cineole synthase) catalyzes the conversion of geranyl pyrophosphate to the symmetrical monoterpene ether 1,8-cineole (1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane) by a process thought to involve the initial isomerization of the substrate to the tertiary allylic isomer, linalyl pyrophosphate, and cyclization of this bound intermediate to the alpha-terpinyl carbocation that is subsequently captured by water and undergoes heterocyclization to the remaining double bond. The enzyme was isolated from the secretory cells of the glandular trichomes of Salvia officinalis (garden sage) and partially purified, and the properties of this monoterpene cyclase, previously determined in crude cell-free extracts, were reexamined. These properties (pH optimum, divalent metal ion requirement, molecular weight, pI) were similar to those determined previously with the exception of substrate utilization; geranyl pyrophosphate was shown to be a more efficient substrate than the cis-isomer, neryl pyrophosphate, in the absence of competing phosphatase activity that contaminated earlier preparations of this enzyme. As with other monoterpene cyclases of herbaceous species, cineole synthase was inhibited by cysteine- and histidine-directed reagents, and protection against inactivation was provided by the substrate-metal ion complex. Studies with 18O-labeled acyclic precursors and H(2)18O, followed by mass spectrometric analysis of the product, confirmed that water was the sole source of the ether oxygen atom of 1,8-cineole. The electrophilic nature of the coupled isomerization-cyclization reaction was examined with a series of substrate and intermediate analogues. The overall stereochemistry of the cyclization of geranyl pyrophosphate to the symmetrical monoterpene was established by determining the enantioselectivity for (3R)- or (3S)-linalyl pyrophosphate as an alternative substrate and by oxidation of [3-3H]1,8-cineole, derived from [1-3H]geranyl pyrophosphate, to (+/-)-3-keto-1,8-cineole and radio-GLC separation of diastereomeric ketal derivatives to determine the labeled enantiomer. << Less

  Arch Biochem Biophys 309:184-192(1994) [PubMed] [EuropePMC]