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Han M.,University of Heidelberg | Heppel S.C.,University of Heidelberg | Su T.,University of Heidelberg | Bogs J.,Dienstleistungszentrum Landlicher Raum Rheinpfalz | And 3 more authors.
PLoS ONE | Year: 2013

In Catharanthus roseus, the monoterpene moiety exerts a strong flux control for monoterpene indole alkaloid (MIA) formation. Monoterpene synthesis depends on the methyl-D-erythritol 4-phosphate (MEP) pathway. Here, we have explored the regulation of this pathway in response to developmental and environmental cues and in response to specific enzyme inhibitors. For the MEP pathway entry enzyme 1-deoxy-D-xylulose 5-phosphate synthase (DXS), a new (type I) DXS isoform, CrDXS1, has been cloned, which, in contrast to previous reports on type II CrDXS, was not transcriptionally activated by the transcription factor ORCA3. Regulation of the MEP pathway in response to metabolic perturbations has been explored using the enzyme inhibitors clomazone (precursor of 5-ketochlomazone, inhibitor of DXS) and fosmidomycin (inhibitor of deoxyxylulose 5-phosphate reductoisomerase (DXR)), respectively. Young leaves of non-flowering plants were exposed to both inhibitors, adopting a non-invasive in vivo technique. Transcripts and proteins of DXS (3 isoforms), DXR, and hydroxymethylbutenyl diphosphate synthase (HDS) were monitored, and protein stability was followed in isolated chloroplasts. Transcripts for DXS1 were repressed by both inhibitors, whereas transcripts for DXS2A&B, DXR and HDS increased after clomazone treatment but were barely affected by fosmidomycin treatment. DXS protein accumulated in response to both inhibitors, whereas DXR and HDS proteins were less affected. Fosmidomycin-induced accumulation of DXS protein indicated substantial posttranscriptional regulation. Furthermore, fosmidomycin effectively protected DXR against degradation in planta and in isolated chloroplasts. Thus our results suggest that DXR protein stability may be affected by substrate binding. In summary, the present results provide novel insight into the regulation of DXS expression in C. roseus in response to MEP-pathway perturbation. © 2013 Han et al. Source


Becker T.,Dienstleistungszentrum Landlicher Raum Rheinpfalz | Knoche M.,Leibniz University of Hanover
Vitis - Journal of Grapevine Research | Year: 2012

The objectives of this study were to quantify deposition, strain, and microcracking of the cuticular membrane (CM) in developing 'Riesling' (Vitis vinifera L.) berries. Mass of the CM, the cutin matrix (DCM), and wax increased pre-veraison (26 to 65 days after anthesis, DAA) on a berry (+ 236, + 211, and + 332 %, respectively) and a surface area basis (+ 11, + 3, and + 43 %, respectively). Post-veraison (65 to 138 DAA), CM and DCM mass per berry remained about constant at 3.4 (± 0.16) and 2.4 (± 0.11) mg per berry, respectively, while wax mass continued to increase from 0.8 (± 0.02) to 1.1 (± 0.02) mg per berry. On an area basis, however, CM and cutin mass decreased from 5.0 (± 0.13) to 4.6 (± 0.04) g·m -2 and from 3.5 (± 0.10) to 3.2 (± 0.03) g·m -2 between 65 and 138 DAA, respectively, but wax mass remained constant at about 1.5 (± 0.04) g·m -2. The calculated rate of cutin and wax deposition peaked at about 40 DAA, and declined continuously thereafter. There was no strain and no microcracking of the CM up to veraison. Post-veraison strain of the CM and microcracking in the stylar scar region increased linearly with time. The data suggest that the cessation of cutin deposition in post-veraison berries and the ongoing berry expansion resulted in increased strain of the CM which in turn caused microcracking in the CM. Source


Schmarr H.-G.,Dienstleistungszentrum Landlicher Raum Rheinpfalz | Schmarr H.-G.,TU Munich | Engel K.-H.,TU Munich
European Food Research and Technology | Year: 2012

Contents and enantiomeric distributions of linalool (3,7-dimethyl-1,6-octadien-3-ol) were investigated in raw and roasted cocoa beans (seeds of Theobroma cacao) of defined origin as well as in commercial products, such as cocoa powders or chocolates. The stereodifferentiation of linalool was achieved by enantioselective multidimensional gas chromatography using heptakis (2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin as chiral stationary phase. Simultaneous steam distillation-extraction at pH 7 allowed sample preparation without racemization of linalool. Cocoa beans contain linalool primarily as (S)-enantiomer. Model experiments and analyses of commercial products such as cocoa powders and chocolates revealed that technological procedures employed in the manufacturing of cocoa products do not result in significant changes of the original enantiomeric distribution of linalool. © 2012 Springer-Verlag. Source


Rossberg D.,Julius Kuhn Institute | Harzer U.,Dienstleistungszentrum Landlicher Raum Rheinpfalz
Journal fur Kulturpflanzen | Year: 2015

Surveys of the application of plant protection products (PPP) in apple farming have been carried out since 2001 (NEPTUN projects). Since 2011, they have been continued under different legislative frameworks as PAPA surveys. PAPA stands for panel pesticide applications. A number of crop-specific networks of farms have been created, in which the PPP application data are recorded in detail annually. The data are forwarded in an anonymised form to the Julius Kühn-Institute (JKI). All surveys and analyses relate to the Federal Republic of Germany. The distribution of the panel farms was proportional to the distribution of growing areas of apples. Survey results show that the plant protection intensity has established itself in apple growing for years at a constant level. A reduction in the number of chemical plant protection measures are not expected in the coming years. The increasing incidence of new invasive pests and the expected lower availability of insecticidal agents (associated with an increased risk of resistance) probably require more additional applications of chemical pesticides to produce apples in sufficient quantity and of marketable quality. © 2015, Verlag Eugen Ulmer. All rights reserved. Source


Balmer M.,Dienstleistungszentrum Landlicher Raum Rheinpfalz
Erwerbs-Obstbau | Year: 2015

On a study visit to the south-east and south of Australia in December 2014, fruit farmers got an impression of the Australian sweet cherry production. The cultivation is export oriented, requiring high standards of sorting, packing and freshness. Large production units, low tree forms such as the Spanish bush or Kym-Green Bush and a high level of automation for sorting and packing help to reduce costs despite of high wages. Through closer proximity to major customers in East Asia compared to the Chilean competitor and the use of air freight prices can be realized, which make production economically. © 2015, Springer-Verlag Berlin Heidelberg. Source

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