Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Mittasch, J.; Böttcher, C.; Frolov, A.; Strack, D.; Milkowski, C.;Reprogramming the Phenylpropanoid Metabolism in Seeds of Oilseed Rape by Suppressing the Orthologs of REDUCED EPIDERMAL FLUORESCENCE1J. Plant Physiol.1611656-1669(2013)DOI: 10.1104/pp.113.215491
As a result of the phenylpropanoid pathway, many Brassicaceae produce considerable amounts of soluble hydroxycinnamate conjugates, mainly sinapate esters. From oilseed rape (Brassica napus), we cloned two orthologs of the Arabidopsis (Arabidopsis thaliana) gene REDUCED EPIDERMAL FLUORESCENCE1 (REF1) encoding a coniferaldehyde/sinapaldehyde dehydrogenase. The enzyme is involved in the formation of ferulate and sinapate from the corresponding aldehydes, thereby linking lignin and hydroxycinnamate biosynthesis as a potential branch-point enzyme. We used RNA interference to silence REF1 genes in seeds of oilseed rape. Nontargeted metabolite profiling showed that BnREF1-suppressing seeds produced a novel chemotype characterized by reduced levels of sinapate esters, the appearance of conjugated monolignols, dilignols, and trilignols, altered accumulation patterns of kaempferol glycosides, and changes in minor conjugates of caffeate, ferulate, and 5-hydroxyferulate. BnREF1 suppression affected the level of minor sinapate conjugates more severely than that of the major component sinapine. Mapping of the changed metabolites onto the phenylpropanoid metabolic network revealed partial redirection of metabolic sequences as a major impact of BnREF1 suppression.
Publikation
Cenzano, A.; Abdala, G.; Hause, B.;Cytochemical immuno-localization of allene oxide cyclase, a jasmonic acid biosynthetic enzyme, in developing potato stolonsJ. Plant Physiol.1641449-1456(2007)DOI: 10.1016/j.jplph.2006.10.007
The involvement of jasmonates in the tuber development has been proved by the presence of many of these compounds in potato stolons, modification of their levels during the transition of the stolon into tuber, and induction of cell expansion upon exogenous jasmonates treatment. However, to date there is only little evidence of the presence of the jasmonic acid-biosynthetic enzymes in stolons or young tubers. As allene oxide cyclase represents the major control point for jasmonic acid biosynthesis, we studied the occurrence of allene oxide cyclase by immunological approaches in the early stages of tuber formation. In developing stolons, allene oxide cyclase as well as lipoxygenase were clearly detectable, but their levels did not change during development. Jasmonic acid treatment for 24 h, however, increased lipoxygenase and allene oxide cyclase protein levels in both developmental stages analyzed. In longitudinal sections of stolons of stages 1 and 2, allene oxide cyclase and lipoxygenase occurred in the apex and along the stolon axis. Allene oxide cyclase was clearly detectable in epidermal, cortical and pith parenchymatic cells, showing the highest levels in vascular tissues surrounding cells. Lipoxygenase was mainly located in the parenchymatic cortex cells. The occurrence of allene oxide cyclase in stolons together with the previous identification of jasmonates from developing stolons reveals that these organs are capable to synthesize and metabolize jasmonates.