Monoterpene synthase activities in leaves of Picea abies (L.) Karst. and Quercus ilex L.

Fischbach, Robert J.; Zimmer, Ina; Steinbrecher, R.; Pfichner, Andreas; Schnitzler, Jörg‐Peter

doi:10.1016/s0031-9422(00)00119-9

Cited by 75 publications

(88 citation statements)

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“…Furthermore, the enzymatic activity determined in vitro does not necessarily reflect the activity in vivo. Especially under stress conditions the concentrations of substrates and cofactors or the cellular pH may differ from in vitro conditions, which may potentially affect the activity status since mono-TPS activities display a very sharp pH optimum in vitro at 6.7 (Fischbach et al, 2000). On the other hand, in the present study both in vitro and field emission measurements showed similar product patterns with consistent between-tree differences suggesting that the in vitro assays indeed reproduced the foliar in vivo enzyme activities.…”

Section: Discussionsupporting

confidence: 65%

“…After measurements the enclosed leaf was frozen in liquid N 2 and stored at −80 • C until mono-TPS analysis as described in Fischbach et al (2000). 250 mg of frozen leaves were homogenised in liquid N 2 , suspended in 6 mL extraction buffer (700 mM Mops/HCl pH 7.3 containing 1.5% (v/v) PEG 1500, 1% (w/v) PVP-30, 8.3% (w/v) Dowex 1x2, 20 mM MgCl 2 , antioxidants [200 mM ascorbic acid, 50 mM β-mercaptoethanol]) and stirred on ice for 20 min.…”

Section: Monoterpene Synthase Activitymentioning

confidence: 99%

“…250 µM) for 60 min at 40 • C. Reactions were terminated by removing the reaction mixture and washing the gas-tight vials with 100 µL assay buffer. GC/FID analysis was performed according to Fischbach et al (2000).…”

Section: Monoterpene Synthase Activitymentioning

confidence: 99%

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Drought reduced monoterpene emissions from the evergreen Mediterranean oak <i>Quercus ilex</i>: results from a throughfall displacement experiment

et al. 2009

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Abstract. The effects of water limitations on the emission of biogenic volatile organic compounds are not well understood. Experimental approaches studying drought effects in natural conditions are still missing. To address this question, a throughfall displacement experiment was set up in a natural forest of Quercus ilex, an evergreen Mediterranean oak emitting monoterpenes. Mature trees were exposed in 2005 and 2006 either to an additional drought, to irrigation or to natural drought (untreated control). In both years, absolute monoterpene emission rates as well as the respective standard factors of the trees exposed to normal and additional drought strongly declined during the drought periods. Monoterpene emissions were lower in year 2006 than in year 2005 (factor 2) due to a more pronounced summer drought period in this respective year. We observed a significant difference between the irrigation and additional drought or control treatment: irrigated trees emitted 82% more monoterpenes during the drought period 2006 than the trees of the other treatments. However, no significant effect on monoterpene emission was observed between normal and additional drought treatments, despite a significant effect on leaf water potential and photochemical efficiency. During the development of drought, monoterpene emissions responded exponentially rather than linearly to decreasing leaf water potential. Emissions rapidly declined when the water potential dropped beCorrespondence to: A.-V. Lavoir (avlavoir@gmail.com) low −2 MPa and photosynthesis was persistently inhibited. Monoterpene synthase activities measured in vitro showed no clear reduction during the same period. From our results we conclude that drought significantly reduces monoterpene fluxes of Mediterranean Holm oak forest into the atmosphere due to a lack of primary substrates coming from photosynthetic processes.

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Section: Discussionsupporting

confidence: 65%

Section: Monoterpene Synthase Activitymentioning

confidence: 99%

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Drought reduced monoterpene emissions from the evergreen Mediterranean oak <i>Quercus ilex</i>: results from a throughfall displacement experiment

et al. 2009

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“…Related monoterpene synthases have K m s for their substrate, geranyl diphosphate, between 10 and 100 mM (Fischbach et al, 2000) and sometimes as low as 2.6 mM (Alonso and Croteau, 1991). The results presented here show that in situ the K m for the allylic diphosphate substrate is much higher for isoprene synthase than for the related monoterpene synthases.…”

Section: Miller Et Al 2001mentioning

confidence: 59%

Rapid Regulation of the Methylerythritol 4-Phosphate Pathway during Isoprene Synthesis

et al. 2004

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More volatile organic carbon is lost from plants as isoprene than any other molecule. This flux of carbon to the atmosphere affects atmospheric chemistry and can serve as a substrate for ozone production in polluted air. Isoprene synthesis may help leaves cope with heatflecks and active oxygen species. Isoprene synthase, an enzyme related to monoterpene synthases, converts dimethylallyl diphosphate derived from the methylerythritol 4-phosphate pathway to isoprene. We used dideuterated deoxyxylulose (DOX-d 2 ) to study the regulation of the isoprene biosynthetic pathway. Exogenous DOX-d 2 displaced endogenous sources of carbon for isoprene synthesis without increasing the overall rate of isoprene synthesis. However, at higher concentrations, DOX-d 2 completely suppressed isoprene synthesis from endogenous sources and increased the overall rate of isoprene synthesis. We interpret these results to indicate strong feedback control of deoxyxylulose-5-phosphate synthase. We related the emission of labeled isoprene to the concentration of labeled dimethylallyl diphosphate in order to estimate the in situ K m of isoprene synthase. The results confirm that isoprene synthase has a K m 10-to 100-fold higher for its allylic diphosphate substrate than related monoterpene synthases for geranyl diphosphate.Isoprene is emitted from many plants, including mosses, ferns, gymnosperms, and angiosperms (Kesselmeier and Staudt, 1999;). Isoprene emission from plants is one of the most important sources of volatile organic compounds released to the atmosphere (Fehsenfeld et al., 1992;Guenther et al., 1995Guenther et al., , 2000Fuentes et al., 2000). Isoprene emission has been hypothesized to provide leaves protection from heat damage (Sharkey and Singsaas, 1995), especially during short heatflecks , and to protect against ozone and other active oxygen species (Loreto and Velikova, 2001;Affek and Yakir, 2002). Isoprene is made in chloroplasts from dimethylallyl diphosphate (DMAPP) by isoprene synthase Fall, 1991, 1995;Schnitzler et al., 1996), an enzyme related to monoterpene synthases (Miller et al., 2001). Monoterpene synthases have a high affinity for their substrate, geranyl diphosphate (K m in the micromolar range), but isoprene synthases examined to date have a much lower affinity (K m s in the millimolar range; Wildermuth and Fall, 1996;Lehning et al., 1999).Isoprene is made mostly from carbon previously fixed by photosynthesis (Delwiche and Sharkey, 1993;Karl et al., 2002;Affek and Yakir, 2003). A low but significant amount (10%-30%) of the carbon in isoprene is not rapidly labeled when 13 CO 2 is fed to leaves, about the same proportion of carbon in phosphoglyceric acid that is not quickly labeled (Atkins and Canvin, 1971). Current hypotheses are that this slowly labeling pool is pyruvate imported into the chloroplast to be joined with glyceraldehyde 3-phosphate (GAP) in the first step of the methyl erythritol 4-phosphate (MEP) pathway, which supplies carbon for isoprene synthesis (Kreuzwieser et al., 2002;Rosenstiel et al., ...

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“…Measurements of leaf scale emissions are taken from Grote et al (2009a) and Lavoir et al (2009) Enzyme activity has been determined in 2006 according to standard protocols described in Fischbach et al (2000) using the same leaves as used for emission measurements. Enzymatic data provide calibration information for the seasonal dynamics model SIM.…”

Section: Site Description and Data Availabilitymentioning

confidence: 99%

Process-based simulation of seasonality and drought stress in monoterpene emission models

et al. 2010

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Abstract. Canopy emissions of volatile hydrocarbons such as isoprene and monoterpenes play an important role in air chemistry. They depend on various environmental conditions, are highly species-specific and are expected to be affected by global change. In order to estimate future emissions of these isoprenoids, differently complex models are available. However, seasonal dynamics driven by phenology, enzymatic activity, or drought stress strongly modify annual ecosystem emissions. Although these impacts depend themselves on environmental conditions, they have yet received little attention in mechanistic modelling.In this paper we propose the application of a mechanistic method for considering the seasonal dynamics of emission potential using the "Seasonal Isoprenoid synthase Model" (Lehning et al., 2001). We test this approach with three different models (GUENTHER, Guenther et al., 1993; NI-INEMETS, Niinemets et al., 2002a; BIM2, Grote et al., 2006) that are developed for simulating light-dependent monoterpene emission. We also suggest specific drought stress representations for each model. Additionally, the proposed model developments are compared with the approach realized in the MEGAN (Guenther et al., 2006) emission model. Models are applied to a Mediterranean Holm oak (Quercus ilex) site with measured weather data.The simulation results demonstrate that the consideration of a dynamic emission potential has a strong effect on annual monoterpene emission estimates. The investigated models, however, show different sensitivities to the procedure for determining this seasonality impact. Considering a drought impact reduced the differences between the applied models and decreased emissions at the investigation site by approxiCorrespondence to: R. Grote (ruediger.grote@imk.fzk.de) mately 33% on average over a 10 year period. Although this overall reduction was similar in all models, the sensitivity to weather conditions in specific years was different. We conclude that the proposed implementations of drought stress and internal seasonality strongly reduce estimated emissions and indicate the measurements that are needed to further evaluate the models.

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Monoterpene synthase activities in leaves of Picea abies (L.) Karst. and Quercus ilex L.

Cited by 75 publications

References 25 publications

Drought reduced monoterpene emissions from the evergreen Mediterranean oak <i>Quercus ilex</i>: results from a throughfall displacement experiment

Drought reduced monoterpene emissions from the evergreen Mediterranean oak <i>Quercus ilex</i>: results from a throughfall displacement experiment

Rapid Regulation of the Methylerythritol 4-Phosphate Pathway during Isoprene Synthesis

Process-based simulation of seasonality and drought stress in monoterpene emission models

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Monoterpene synthase activities in leaves of Picea abies (L.) Karst. and Quercus ilex L.

Cited by 75 publications

References 25 publications

Drought reduced monoterpene emissions from the evergreen Mediterranean oak &lt;i&gt;Quercus ilex&lt;/i&gt;: results from a throughfall displacement experiment

Drought reduced monoterpene emissions from the evergreen Mediterranean oak &lt;i&gt;Quercus ilex&lt;/i&gt;: results from a throughfall displacement experiment

Rapid Regulation of the Methylerythritol 4-Phosphate Pathway during Isoprene Synthesis

Process-based simulation of seasonality and drought stress in monoterpene emission models

Contact Info

Product

Resources

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Drought reduced monoterpene emissions from the evergreen Mediterranean oak <i>Quercus ilex</i>: results from a throughfall displacement experiment

Drought reduced monoterpene emissions from the evergreen Mediterranean oak <i>Quercus ilex</i>: results from a throughfall displacement experiment