@article {Ringer:2005p8013,
	title = {Monoterpene metabolism. Cloning, expression, and characterization of (-)-isopiperitenol/(-)-carveol dehydrogenase of peppermint and spearmint},
	journal = {Plant Physiol},
	volume = {137},
	number = {3},
	year = {2005},
	month = {Mar},
	pages = {863{\textendash}72},
	abstract = {The essential oils of peppermint (Mentha x piperita) and spearmint (Mentha spicata) are distinguished by the oxygenation position on the p-menthane ring of the constitutive monoterpenes that is conferred by two regiospecific cytochrome P450 limonene-3- and limonene-6-hydroxylases. Following hydroxylation of limonene, an apparently similar dehydrogenase oxidizes (-)-trans-isopiperitenol to (-)-isopiperitenone in peppermint and (-)-trans-carveol to (-)-carvone in spearmint. Random sequencing of a peppermint oil gland secretory cell cDNA library revealed a large number of clones that specified redox-type enzymes, including dehydrogenases. Full-length dehydrogenase clones were screened by functional expression in Escherichia coli using a recently developed in situ assay. A single full-length acquisition encoding (-)-trans-isopiperitenol dehydrogenase (ISPD) was isolated. The (-)-ISPD cDNA has an open reading frame of 795 bp that encodes a 265-residue enzyme with a calculated molecular mass of 27,191. Nondegenerate primers were designed based on the (-)-trans-ISPD cDNA sequence and employed to screen a spearmint oil gland secretory cell cDNA library from which a 5{\textquoteright}-truncated cDNA encoding the spearmint homolog, (-)-trans-carveol-dehydrogenase, was isolated. Reverse transcription-PCR amplification and RACE were used to acquire the remaining 5{\textquoteright}-sequence from RNA isolated from oil gland secretory cells of spearmint leaf. The full-length spearmint dehydrogenase shares >99\% amino acid identity with its peppermint homolog and both dehydrogenases are capable of utilizing (-)-trans-isopiperitenol and (-)-trans-carveol. These isopiperitenol/carveol dehydrogenases are members of the short-chain dehydrogenase/reductase superfamily and are related to other plant short-chain dehydrogenases/reductases involved in secondary metabolism (lignan biosynthesis), stress responses, and phytosteroid biosynthesis, but they are quite dissimilar (approximately 13\% identity) to the monoterpene reductases of mint involved in (-)-menthol biosynthesis. The isolation of the genes specifying redox enzymes of monoterpene biosynthesis in mint indicates that these genes arose from different ancestors and not by simple duplication and differentiation of a common progenitor, as might have been anticipated based on the common reaction chemistry and structural similarity of the substrate monoterpenes.},
	keywords = {Alcohol Oxidoreductases, Amino Acid Sequence, Cloning: Molecular, Mentha piperita, Mentha spicata, Molecular Sequence Data, Molecular Structure, Monoterpenes, Multigene Family, Oils: Volatile, Phylogeny},
	doi = {10.1104/pp.104.053298},
	author = {Kerry L Ringer and Edward M Davis and Rodney Croteau}
}
@article {Iijima:2004p8022,
	title = {The biochemical and molecular basis for the divergent patterns in the biosynthesis of terpenes and phenylpropenes in the peltate glands of three cultivars of basil},
	journal = {Plant Physiol},
	volume = {136},
	number = {3},
	year = {2004},
	month = {Nov},
	pages = {3724{\textendash}36},
	abstract = {Surface glandular trichomes distributed throughout the aerial parts of sweet basil (Ocimum basilicum) produce and store monoterpene, sesquiterpene, and phenylpropene volatiles. Three distinct basil chemotypes were used to examine the molecular mechanisms underlying the divergence in their monoterpene and sesquiterpene content. The relative levels of specific terpenes in the glandular trichomes of each cultivar were correlated with the levels of transcripts for eight genes encoding distinct terpene synthases. In a cultivar that produces mostly (R)-linalool, transcripts of (R)-linalool synthase (LIS) were the most abundant of these eight. In a cultivar that synthesizes mostly geraniol, transcripts of geraniol synthase were the most abundant, but the glands of this cultivar also contained a transcript of an (R)-LIS gene with a 1-base insertion that caused a frameshift mutation. A geraniol synthase-LIS hybrid gene was constructed and expressed in Escherichia coli, and the protein catalyzed the formation of both geraniol and (R)-linalool from geranyl diphosphate. The total amounts of terpenes were correlated with total levels of terpene synthase activities, and negatively correlated with levels of phenylpropanoids and phenylalanine ammonia lyase activity. The relative levels of geranyl diphosphate synthase and farnesyl diphosphate synthase activities did not correlate with the total amount of terpenes produced, but showed some correlation with the ratio of monoterpenes to sesquiterpenes.},
	keywords = {Amino Acid Sequence, Gene Expression Regulation: Plant, Genetic Variation, Molecular Sequence Data, Molecular Structure, Ocimum basilicum, Phylogeny, Sequence Homology: Amino Acid, Styrenes, Terpenes},
	doi = {10.1104/pp.104.051318},
	author = {Yoko Iijima and Rachel Davidovich-Rikanati and Eyal Fridman and David R Gang and Einat Bar and Efraim Lewinsohn and Eran Pichersky}
}
@article {TapernouxLuthi:2004p8016,
	title = {Cloning, functional expression, and characterization of the raffinose oligosaccharide chain elongation enzyme, galactan:galactan galactosyltransferase, from common bugle leaves},
	journal = {Plant Physiol},
	volume = {134},
	number = {4},
	year = {2004},
	month = {Apr},
	pages = {1377{\textendash}87},
	abstract = {Galactan:galactan galactosyltransferase (GGT) is a unique enzyme of the raffinose family oligosaccharide (RFO) biosynthetic pathway. It catalyzes the chain elongation of RFOs without using galactinol (alpha-galactosyl-myoinositol) by simply transferring a terminal alpha-galactosyl residue from one RFO molecule to another one. Here, we report the cloning and functional expression of a cDNA encoding GGT from leaves of the common bugle (Ajuga reptans), a winter-hardy long-chain RFO-storing Lamiaceae. The cDNA comprises an open reading frame of 1215 bp. Expression in tobacco (Nicotiana plumbaginifolia) protoplasts resulted in a functional recombinant protein, which showed GGT activity like the previously described purified, native GGT enzyme. At the amino acid level, GGT shows high homologies (>60\%) to acid plant alpha-galactosidases of the family 27 of glycosylhydrolases. It is clearly distinct from the family 36 of glycosylhydrolases, which harbor galactinol-dependent raffinose and stachyose synthases as well as alkaline alpha-galactosidases. Physiological studies on the role of GGT confirmed that GGT plays a key role in RFO chain elongation and carbon storage. When excised leaves were exposed to chilling temperatures, levels of GGT transcripts, enzyme activities, and long-chain RFO concentrations increased concomitantly. On a whole-plant level, chilling temperatures induced GGT expression mainly in the roots and fully developed leaves, both known RFO storage organs of the common bugle, indicating an adaptation of the metabolism from active growth to transient storage in the cold.},
	keywords = {Ajuga, Amino Acid Sequence, Cloning: Molecular, Cold Temperature, DNA: Complementary, Galactosyltransferases, Gene Expression Regulation: Enzymologic, Gene Expression Regulation: Plant, Molecular Sequence Data, Phylogeny, Plant Leaves, Plant Proteins, Raffinose, Sequence Analysis: DNA, Sequence Homology: Amino Acid, Tobacco},
	doi = {10.1104/pp.103.036210},
	author = {Esther M Tapernoux-L{\"u}thi and Andreas B{\"o}hm and Felix Keller}
}
@article {Iijima:2004p8034,
	title = {Characterization of geraniol synthase from the peltate glands of sweet basil},
	journal = {Plant Physiol},
	volume = {134},
	number = {1},
	year = {2004},
	month = {Jan},
	pages = {370{\textendash}9},
	abstract = {The monoterpene fraction of the lemon-scented sweet basil (Ocimum basilicum) cv Sweet Dani consists mostly of citral (a mixture of geranial and neral), with lower levels of geraniol and nerol. These compounds are stored in the peltate glands found on the leaf epidermis. Younger leaves, which have a higher density of such glands, also have a higher content of monoterpenes than older leaves. Geraniol synthase (GES) activity, generating geraniol from geranyl diphosphate, was shown to be localized exclusively or almost exclusively to glands. GES activity resides in a homodimeric protein that was purified to near homogeneity. Basil GES requires Mn2+ as a divalent metal cofactor for activity and produces only geraniol from geranyl diphosphate. Km values of 21 and 51 microM were obtained for geranyl diphosphate and Mn2+, respectively. In the presence of 18O-labeled water, GES catalyzed the formation of 18O-geraniol from geranyl diphosphate, indicating that the reaction mechanism of GES is similar to that of other monoterpene synthases and is different from the action of phosphatases. A GES cDNA was isolated based on analysis of a glandular trichome expressed sequence tag database, and the sequence of the protein encoded by this cDNA shows some similarity to sequences of other terpene synthases. The expression of the GES cDNA in Escherichia coli resulted in a protein with enzymatic activity essentially identical to that of plant-purified GES. RNA gel-blot analysis indicated that GES is expressed in glands but not in leaves of basil cv Sweet Dani, whose glands contain geraniol and citral, and not in glands or leaves of another basil variety that makes other monoterpenes but not geraniol or citral.},
	keywords = {Alkyl and Aryl Transferases, Amino Acid Sequence, DNA: Complementary, DNA: Plant, Gene Expression, Genes: Plant, Molecular Sequence Data, Ocimum basilicum, Phylogeny, Plant Structures, Sequence Homology: Amino Acid, Terpenes},
	doi = {10.1104/pp.103.032946},
	author = {Yoko Iijima and David R Gang and Eyal Fridman and Efraim Lewinsohn and Eran Pichersky}
}
