Publications

• Medicago truncatula (E)-beta-ocimene synthase is induced by insect herbivory with corresponding increases in emission of volatile ocimene.

  Navia-Gine W.G., Yuan J.S., Mauromoustakos A., Murphy J.B., Chen F., Korth K.L.

  Virtually all plants are able to recognize attack by herbivorous insects and release volatile organic compounds (VOC) in response. Terpenes are the most abundant and varied class of insect-induced VOC from plants. Four genes encoding putative terpene synthases (MtTps1, MtTps2, MtTps3 and MtTps4) w ... >> More

  Virtually all plants are able to recognize attack by herbivorous insects and release volatile organic compounds (VOC) in response. Terpenes are the most abundant and varied class of insect-induced VOC from plants. Four genes encoding putative terpene synthases (MtTps1, MtTps2, MtTps3 and MtTps4) were shown to accumulate in Medicago truncatula Gaertn. in response to Spodoptera exigua (Hübner) feeding and methyl jasmonate treatment in a previous study [S.K. Gomez, M.M. Cox, J.C. Bede, K.K. Inoue, H.T. Alborn, J.H. Tumlinson, K.L. Korth, Lepidopteran herbivory and oral factors induce transcripts encoding novel terpene synthases in Medicago truncatula, Arch. Insect Biochem. Physiol. 58 (2005) 114-127.] The focus of the current study is the functional characterization of one (MtTps4) of these four genes. Using an M. truncatula cDNA clone, the insect-inducible putative terpene synthase was expressed in Escherichiacoli and shown to convert geranyl diphosphate (GPP) into the monoterpene (E)-beta-ocimene as the major product. The clone was therefore designated M. truncatula (E)-beta-ocimene synthase (MtEBOS). Transcripts encoding this enzyme accumulate in M. truncatula leaves in response to exogenous jasmonic acid treatments, lepidopteran herbivory, and lepidopteran oral secretions. Treatment with the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC) did not cause an increase in MtEBOS transcripts. The volatile (E)-beta-ocimene was released from leaves of both undamaged and insect-damaged plants, but at levels two-fold higher in insect-damaged M. truncatula. Although leaves have low constitutive levels of MtEBOS transcripts, RNA blot analysis indicates no constitutive expression in flowers, stems or roots. The strong insect-induced expression of this gene, and its correspondence with release of volatile ocimene, suggest that it plays an active role in indirect insect defenses in M. truncatula. << Less

  Plant Physiol. Biochem. 47:416-425(2009) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Herbivore-induced defense response in a model legume. Two-spotted spider mites induce emission of (E)-beta-ocimene and transcript accumulation of (E)-beta-ocimene synthase in Lotus japonicus.

  Arimura G., Ozawa R., Kugimiya S., Takabayashi J., Bohlmann J.

  Indirect defense of plants against herbivores often involves the induced emission of volatile infochemicals including terpenoids that attract natural enemies of the herbivores. We report the isolation and characterization of a terpene synthase cDNA (LjEbetaOS) from a model legume, Lotus japonicus. ... >> More

  Indirect defense of plants against herbivores often involves the induced emission of volatile infochemicals including terpenoids that attract natural enemies of the herbivores. We report the isolation and characterization of a terpene synthase cDNA (LjEbetaOS) from a model legume, Lotus japonicus. Recombinant LjEbetaOS enzyme produced (E)-beta-ocimene (98%) and its Z-isomer (2%). Transcripts of LjEbetaOS were induced in L. japonicus plants infested with two-spotted spider mites (Tetranychus urticae), coinciding with increasing emissions of (E)-beta-ocimene as well as other volatiles, (Z)-3-hexenyl acetate and (E)-4,8-dimethyl-1,3,7-nonatriene, by the infested plants. We suggest that LjEbetaOS is involved in the herbivore-induced indirect defense response of spider mite-infested L. japonicus via de novo formation and emission (E)-beta-ocimene. Mechanical wounding of the leaves or application of alamethicin (ALA), a potent fungal elicitor of plant volatile emission, also induced transiently increased levels of LjEbetaOS transcripts in L. japonicus. However, wounding or ALA did not result in elevated release of (E)-beta-ocimene. Differences in volatile emissions after herbivory, mechanical wounding, or treatment with ALA suggest that neither a single mechanical wounding event nor ALA simulate the effect of herbivore activity and indicate that herbivore-induced emission of (E)-beta-ocimene in L. japonicus involves control mechanisms in addition to up-regulation of LjEbetaOS transcripts. << Less

  Plant Physiol. 135:1976-1983(2004) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• (E)-beta-ocimene and myrcene synthase genes of floral scent biosynthesis in snapdragon: function and expression of three terpene synthase genes of a new terpene synthase subfamily.

  Dudareva N., Martin D., Kish C.M., Kolosova N., Gorenstein N., Faeldt J., Miller B., Bohlmann J.

  Snapdragon flowers emit two monoterpene olefins, myrcene and (E)-beta-ocimene, derived from geranyl diphosphate, in addition to a major phenylpropanoid floral scent component, methylbenzoate. Emission of these monoterpenes is regulated developmentally and follows diurnal rhythms controlled by a ci ... >> More

  Snapdragon flowers emit two monoterpene olefins, myrcene and (E)-beta-ocimene, derived from geranyl diphosphate, in addition to a major phenylpropanoid floral scent component, methylbenzoate. Emission of these monoterpenes is regulated developmentally and follows diurnal rhythms controlled by a circadian clock. Using a functional genomics approach, we have isolated and characterized three closely related cDNAs from a snapdragon petal-specific library that encode two myrcene synthases (ama1e20 and ama0c15) and an (E)-beta-ocimene synthase (ama0a23). Although the two myrcene synthases are almost identical (98%), except for the N-terminal 13 amino acids, and are catalytically active, yielding a single monoterpene product, myrcene, only ama0c15 is expressed at a high level in flowers and contributes to floral myrcene emission. (E)-beta-Ocimene synthase is highly similar to snapdragon myrcene synthases (92% amino acid identity) and produces predominantly (E)-beta-ocimene (97% of total monoterpene olefin product) with small amounts of (Z)-beta-ocimene and myrcene. These newly isolated snapdragon monoterpene synthases, together with Arabidopsis AtTPS14 (At1g61680), define a new subfamily of the terpene synthase (TPS) family designated the Tps-g group. Members of this new Tps-g group lack the RRx(8)W motif, which is a characteristic feature of the Tps-d and Tps-b monoterpene synthases, suggesting that the reaction mechanism of Tps-g monoterpene synthase product formation does not proceed via an RR-dependent isomerization of geranyl diphosphate to 3S-linalyl diphosphate, as shown previously for limonene cyclase. Analyses of tissue-specific, developmental, and rhythmic expression of these monoterpene synthase genes in snapdragon flowers revealed coordinated regulation of phenylpropanoid and isoprenoid scent production. << Less

  Plant Cell 15:1227-1241(2003) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• The tomato terpene synthase gene family.

  Falara V., Akhtar T.A., Nguyen T.T.H., Spyropoulou E.A., Bleeker P.M., Schauvinhold I., Matsuba Y., Bonini M.E., Schilmiller A.L., Last R.L., Schuurink R.C., Pichersky E.

  Compounds of the terpenoid class play numerous roles in the interactions of plants with their environment, such as attracting pollinators and defending the plant against pests. We show here that the genome of cultivated tomato (Solanum lycopersicum) contains 44 terpene synthase (TPS) genes, includ ... >> More

  Compounds of the terpenoid class play numerous roles in the interactions of plants with their environment, such as attracting pollinators and defending the plant against pests. We show here that the genome of cultivated tomato (Solanum lycopersicum) contains 44 terpene synthase (TPS) genes, including 29 that are functional or potentially functional. Of these 29 TPS genes, 26 were expressed in at least some organs or tissues of the plant. The enzymatic functions of eight of the TPS proteins were previously reported, and here we report the specific in vitro catalytic activity of 10 additional tomato terpene synthases. Many of the tomato TPS genes are found in clusters, notably on chromosomes 1, 2, 6, 8, and 10. All TPS family clades previously identified in angiosperms are also present in tomato. The largest clade of functional TPS genes found in tomato, with 12 members, is the TPS-a clade, and it appears to encode only sesquiterpene synthases, one of which is localized to the mitochondria, while the rest are likely cytosolic. A few additional sesquiterpene synthases are encoded by TPS-b clade genes. Some of the tomato sesquiterpene synthases use z,z-farnesyl diphosphate in vitro as well, or more efficiently than, the e,e-farnesyl diphosphate substrate. Genes encoding monoterpene synthases are also prevalent, and they fall into three clades: TPS-b, TPS-g, and TPS-e/f. With the exception of two enzymes involved in the synthesis of ent-kaurene, the precursor of gibberellins, no other tomato TPS genes could be demonstrated to encode diterpene synthases so far. << Less

  Plant Physiol. 157:770-789(2011) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Terpenoid secondary metabolism in Arabidopsis thaliana: cDNA cloning, characterization, and functional expression of a myrcene/(E)-beta-ocimene synthase.

  Bohlmann J., Martin D., Oldham N.J., Gershenzon J.

  The Arabidopsis genome project has recently reported sequences with similarity to members of the terpene synthase (TPS) gene family of higher plants. Surprisingly, several Arabidopsis terpene synthase-like sequences (AtTPS) share the most identity with TPS genes that participate in secondary metab ... >> More

  The Arabidopsis genome project has recently reported sequences with similarity to members of the terpene synthase (TPS) gene family of higher plants. Surprisingly, several Arabidopsis terpene synthase-like sequences (AtTPS) share the most identity with TPS genes that participate in secondary metabolism in terpenoid-accumulating plant species. Expression of a putative Arabidopsis terpene synthase gene, designated AtTPS03, was demonstrated by amplification of a 392-bp cDNA fragment using primers designed to conserved regions of plant terpene synthases. Using the AtTPS03 fragment as a hybridization probe, a second AtTPS cDNA, designated AtTPS10, was isolated from a jasmonate-induced cDNA library. The partial AtTPS10 cDNA clone contained an open reading frame of 1665 bp encoding a protein of 555 amino acids. Functional expression of AtTPS10 in Escherichia coli yielded an active monoterpene synthase enzyme, which converted geranyl diphosphate (C(10)) into the acyclic monoterpenes beta-myrcene and (E)-beta-ocimene and small amounts of cyclic monoterpenes. Based on sequence relatedness, AtTPS10 was classified as a member of the TPSb subfamily of angiosperm monoterpene synthases. Sequence comparison of AtTPS10 with previously cloned monoterpene synthases suggests independent events of functional specialization of terpene synthases during the evolution of terpenoid secondary metabolism in gymnosperms and angiosperms. Functional characterization of the AtTPS10 gene was prompted by the availability of Arabidopsis genome sequences. Although Arabidoposis has not been reported to form terpenoid secondary metabolites, the unexpected expression of TPS genes belonging to the TPSb subfamily in this species strongly suggests that terpenoid secondary metabolism is active in the model system Arabidopsis. << Less

  Arch. Biochem. Biophys. 375:261-269(2000) [PubMed] [EuropePMC]