jump to searchjump to navigationjump to content

Publications - Stress and Develop Biology

Sort by: Year Type of publication

Displaying results 1 to 5 of 5.

Publications

von Roepenack-Lahaye, E.; Degenkolb, T.; Zerjeski, M.; Franz, M.; Roth, U.; Wessjohann, L.; Schmidt, J.; Scheel, D.; Clemens, S.; Profiling of Arabidopsis Secondary Metabolites by Capillary Liquid Chromatography Coupled to Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry Plant Physiol. 134, 548-559, (2004) DOI: 10.1104/pp.103.032714

Large-scale metabolic profiling is expected to develop into an integral part of functional genomics and systems biology. The metabolome of a cell or an organism is chemically highly complex. Therefore, comprehensive biochemical phenotyping requires a multitude of analytical techniques. Here, we describe a profiling approach that combines separation by capillary liquid chromatography with the high resolution, high sensitivity, and high mass accuracy of quadrupole time-of-flight mass spectrometry. About 2,000 different mass signals can be detected in extracts of Arabidopsis roots and leaves. Many of these originate from Arabidopsis secondary metabolites. Detection based on retention times and exact masses is robust and reproducible. The dynamic range is sufficient for the quantification of metabolites. Assessment of the reproducibility of the analysis showed that biological variability exceeds technical variability. Tools were optimized or established for the automatic data deconvolution and data processing. Subtle differences between samples can be detected as tested with the chalcone synthase deficient tt4 mutant. The accuracy of time-of-flight mass analysis allows to calculate elemental compositions and to tentatively identify metabolites. In-source fragmentation and tandem mass spectrometry can be used to gain structural information. This approach has the potential to significantly contribute to establishing the metabolome of Arabidopsis and other model systems. The principles of separation and mass analysis of this technique, together with its sensitivity and resolving power, greatly expand the range of metabolic profiling.
Publications

Landtag, J.; Baumert, A.; Degenkolb, T.; Schmidt, J.; Wray, V.; Scheel, D.; Strack, D.; Rosahl, S.; Accumulation of tyrosol glucoside in transgenic potato plants expressing a parsley tyrosine decarboxylase Phytochemistry 60, 683-689, (2002) DOI: 10.1016/S0031-9422(02)00161-9

As part of the response to pathogen infection, potato plants accumulate soluble and cell wall-bound phenolics such as hydroxycinnamic acid tyramine amides. Since incorporation of these compounds into the cell wall leads to a fortified barrier against pathogens, raising the amounts of hydroxycinnamic acid tyramine amides might positively affect the resistance response. To this end, we set out to increase the amount of tyramine, one of the substrates of the hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)-transferase reaction, by placing a cDNA encoding a pathogen-induced tyrosine decarboxylase from parsley under the control of the 35S promoter and introducing the construct into potato plants via Agrobacterium tumefaciens-mediated transformation. While no alterations were observed in the pattern and quantity of cell wall-bound phenolic compounds in transgenic plants, the soluble fraction contained several new compounds. The major one was isolated and identified as tyrosol glucoside by liquid chromatography–electrospray ionization–high resolution mass spectrometry and NMR analyses. Our results indicate that expression of a tyrosine decarboxylase in potato does not channel tyramine into the hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)-transferase reaction but rather unexpectedly, into a different pathway leading to the formation of a potential storage compound.Expression of a parsley tyrosine decarboxylase in potato unexpectedly channels tyramine into a pathway leading to the formation of tyrosol glucoside.
Publications

Weiss, M.; Schmidt, J.; Neumann, D.; Wray, V.; Christ, R.; Strack, D.; Phenylpropanoids in mycorrhizas of the Pinaceae Planta 208, 491-502, (1999) DOI: 10.1007/s004250050586

Tissue-specific accumulation of phenylpropanoids was studied in mycorrhizas of the conifers, silver fir (Abies alba Mill.), Norway spruce [Picea abies (L.) Karst.], white pine (Pinus strobus L.), Scots pine (Pinus silvestris L.), and Douglas fir [Pseudotsuga menziesii (Mirbel) Franco], using high-performance liquid chromatography and histochemical methods. The compounds identified were soluble flavanols (catechin and epicatechin), proanthocyanidins (mainly dimeric catechins and/or epicatechins), stilbene glucosides (astringin and isorhapontin), one dihydroflavonol glucoside (taxifolin 3′-O-glucopyranoside), and a hydroxycinnamate derivative (unknown ferulate conjugate). In addition, a cell wall-bound hydroxycinnamate (ferulate) and a hydroxybenzaldehyde (vanillin) were analysed. Colonisation of the root by the fungal symbiont correlated with the distribution pattern of the above phenylpropanoids in mycorrhizas suggesting that these compounds play an essential role in restricting fungal growth. The levels of flavanols and cell wall-bound ferulate within the cortex were high in the apical part and decreased to the proximal side of the mycorrhizas. In both Douglas fir and silver fir, which allowed separation of inner and outer parts of the cortical tissues, a characteristic transversal distribution of these compounds was found: high levels in the inner non-colonised part of the cortex and low levels in the outer part where the Hartig net is formed. Restriction of fungal growth to the outer cortex may also be achieved by characteristic cell wall thickening of the inner cortex which exhibited flavanolic wall infusions in Douglas fir mycorrhizas. Long and short roots of conifers from natural stands showed similar distribution patterns of phenylpropanoids and cell wall thickening compared to the respective mycorrhizas. These results are discussed with respect to co-evolutionary adaptation of both symbiotic partners regarding root structure (anatomy) and root chemistry.
Publications

Schmidt, A.; Grimm, R.; Schmidt, J.; Scheel, D.; Strack, D.; Rosahl, S.; Cloning and Expression of a Potato cDNA Encoding Hydroxycinnamoyl-CoA:Tyramine N-(Hydroxycinnamoyl)transferase J. Biol. Chem. 274, 4273-4280, (1999) DOI: 10.1074/jbc.274.7.4273

Hydroxycinnamoyl-CoA:tyramineN-(hydroxycinnamoyl)transferase (THT; EC 2.3.1.110) catalyzes the transfer of hydroxycinnamic acids from the respective CoA esters to tyramine and other amines in the formation ofN-(hydroxycinnamoyl)amines. Expression of THT is induced byPhytophthora infestans, the causative agent of late blight disease in potato. The amino acid sequences of nine endopeptidase LysC-liberated peptides from purified potato THT were determined. Using degenerate primers, a THT-specific fragment was obtained by reverse transcription-polymerase chain reaction, and THT cDNA clones were isolated from a library constructed from RNA of elicitor-treated potato cells. The open reading frame encoding a protein of 248 amino acids was expressed in Escherichia coli. Recombinant THT exhibited a broad substrate specificity, similar to that of native potato THT, accepting cinnamoyl-, 4-coumaroyl-, caffeoyl-, feruloyl- and sinapoyl-CoA as acyl donors and tyramine, octopamine, and noradrenalin as acceptors tested. Elicitor-induced THT transcript accumulation in cultured potato cells peaked 5 h after initiation of treatment, whereas enzyme activity was highest from 5 to 30 h after elicitation. In soil-grown potato plants, THT mRNA was most abundant in roots. Genomic Southern analyses indicate that, in potato, THT is encoded by a multigene family.
Publications

Leopold, I.; Günther, D.; Schmidt, J.; Neumann, D.; Phytochelatins and heavy metal tolerance Phytochemistry 50, 1323-1328, (1999) DOI: 10.1016/S0031-9422(98)00347-1

The induction and heavy metal binding properties of phytochelatins in heavy metal tolerant (Silene vulgaris) and sensitive (tomato) cell cultures, in water cultures of these plants and in Silene vulgaris grown on a medieval copper mining dump were investigated. Application of heavy metals to cell suspension cultures and whole plants of Silene vulgaris and tomato induces the formation of heavy metal–phytochelatin-complexes with Cu and Cd and the binding of Zn and Pb to lower molecular weight substances. The binding of heavy metal ions to phytochelatins seems to play only a transient role in the heavy metal detoxification, because the Cd- and Cu-complexes disappear in the roots of water cultures of Silene vulgaris between 7 and 14 days after heavy metal exposition. Free heavy metal ions were not detectable in the extracts of all investigated plants and cell cultures. Silene vulgaris plants grown under natural conditions on a mining dump synthesize low molecular weight heavy metal binding compounds only and show no complexation of heavy metal ions to phytochelatins. The induction of phytochelatins is a general answer of higher plants to heavy metal exposition, but only some of the heavy metal ions are able to form stable complexes with phytochelatins. The investigation of tolerant plants from the copper mining dump shows that phytochelatins are not responsible for the development of the heavy metal tolerant phenotypes.
IPB Mainnav Search