Showing papers on "Chalcone synthase published in 1985"
TL;DR: Structural similarities of Tam3 and the maize elements Ac/Ds suggest that these elements belong to a common family.
Abstract: The 3.5 kb transposable element, Tam3, has been shown to cause somatic and germinal instability at the nivea locus, which encodes chalcone synthase, of Antirrhinum majus. Molecular cloning and sequence analysis of the niv-98::Tam3 allele revealed that the termini of Tam3 consist of 12 bp perfect inverted repeats. Tam3 is integrated in the promoter region of the chalcone synthase gene and generates an 8 bp duplication of target sequences upon integration. DNA sequencing of a niv
+x revertant, niv-164, revealed a new type of sequence alteration upon excision: the duplications are displaced by ten nucleotides generated from adjacent sequences. Structural similarities of Tam3 and the maize elements Ac/Ds suggest that these elements belong to a common family.
114 citations
TL;DR: It is concluded that expression of the phy toalexin defense response in biologically stressed cells of P. vulgaris characteristically involves co‐ordinate induction of synthesis of phytoaleXin biosynthetic enzymes.
Abstract: Changes in the rates of synthesis of three enzymes of phenyl-propanoid biosynthesis in Phaseolus vulgaris L. (dwarf French bean) have been investigated by immunoprecipitation of [35S]methionine-labeled enzyme subunits with mono-specific antisera. Elicitor causes marked, rapid but transient co-ordinated increases in the rate of synthesis of phenyl-alanine ammonia-lyase, chalcone synthase and chalcone isomerase concomitant with the phase of rapid increase in enzyme activity at the onset of accumulation of phenyl-propanoid-derived phytoalexin antibiotics in suspension cultures of P. vulgaris. Co-ordinate induction of enzyme synthesis is also observed in hypocotyl tissue during race:cultivar-specific interactions with Colletotrichum lindemuthianum, causal agent of anthracnose. In an incompatible interaction (host resistant) there are early increases apparently localized to the initial site of infection prior to the onset of phytoalexin accumulation and expression of hypersensitive resistance. In contrast, in a compatible interaction (host susceptible) there is no induction of synthesis in the early stages of infection, but a delayed widespread response at the onset of lesion formation associated with attempted lesion limitation. It is concluded that expression of the phytoalexin defense response in biologically stressed cells of P. vulgaris characteristically involves co-ordinate induction of synthesis of phytoalexin biosynthetic enzymes.
114 citations
TL;DR: It is reported here that self-cyclisation of naringenin chalcone is dramatically reduced at pH-values ⩽ 6.5 and in the presence of high concentrations of serum albumin.
67 citations
TL;DR: The niv-44 allele is characterised at the molecular level, which contains a 5kb insertion element, Tam 2, which has 14 base pair inverted repeats at the target site of the chalcone synthase gene.
Abstract: Several alleles of the nivea locus of Antirrhinum majus, both stable and unstable, have been characterised genetically (Harrison and Carpenter 1973 a, b). In this work the niv-44 allele is characterised at the molecular level. It contains a 5kb insertion element, Tam 2, which has 14 base pair inverted repeats. There is a three base pair duplication at the target site, which is at the first intron-exon boundary of the chalcone synthase gene. Tam 2 homologous sequences are present in multiple copies in several A. majus lines, including niv-53, and most have at least a 2.9 kb sequence in common with the copy at the chalcone synthase gene. Possible reasons for the apparent stability of the niv-44 allele and molecular explanations for the role of this allele in paramutation in A. majus are discussed.
61 citations
TL;DR: Anthocyaninless vp1 aleurones were found to be deficient in at least three enzymes of flavonoid biosynthesis as well as in several other metabolically unrelated enzymes that show pronounced increases in late stages of aleurone development.
Abstract: The viviparous-1 (vp1) mutation in maize (Zea mays L.) conditions a unique pleiotropic phenotype: premature germination of the embryo and failure to synthesize anthocyanin (flavonoid) pigments in the aleurone. By using a B-A translocation, it is possible to analyze the basis for the anthocyaninless phenotype of vp1 in the absence of vivipary. Anthocyaninless vp1 aleurones were found to be deficient in at least three enzymes of flavonoid biosynthesis (phenylalanine ammonia lyase, chalcone synthase, and UDPG-flavonoid glucosyltransferase) as well as in several other metabolically unrelated enzymes that show pronounced increases in late stages of aleurone development. The set of structural genes encoding such enzymes is postulated to be under the regulation of the vpl gene.
58 citations
TL;DR: It could be demonstrated that the genes on the two fragments from Petunia hybrida containing complete chalcone synthase genes are different and are not allelic but members of a gene family.
Abstract: With the help of a cDNA probe for a chalcone synthase gene of Petroselinum a cDNA clone for a chalcone synthase gene of Petunia hybrida could be identified. The homologous cDNA allowed the cloning of two genomic EcoRI fragments from Petunia hybrida containing complete chalcone synthase genes. It could be demonstrated that the genes on the two fragments are different and are not allelic but members of a gene family. The two genes are found in a variety of different Petunia lines including in the two conditional mutants affected in chalcone synthase expression in floral buds, White Joy and Red Star. The structure of the two chs genes from Petunia is compared to the chs gene from Antirrhinum majus.
57 citations
TL;DR: The results suggest that soybean cells respond to the glucan elicitor by major metabolic changes at the RNA level including the enhanced capacity for phytoalexin synthesis, as indicated by two-dimensional electrophoresis of the translation products.
46 citations
TL;DR: The inclusion of very low levels of an elicitor fraction from the cell walls of Phytophthora megasperma in the medium in which lignification of the soybean cells occurs suppressed both the accumulation of extracellular lignin and phloroglucinol staining of the cell Walls without affecting the levels of bound hydroxycinnamic acids.
Abstract: Soybean (Glycine max L.) cells cultured in B5 medium produce extremely low amounts of lignin. However, modification in the growth medium, by lowering the concentration of NO−3 and PO2−4, results in the lignification of these cells without affecting levels of cell wall-esterified 4-coumaric and ferulic acid. The production of an extracellular, macromolecular complex by the cultured soybean cells (Moore TS Jr 1973 Plant Physiol 51: 529-536) allows a rapid, nondestructive solubilization of the lignin which can be estimated by reaction with phloroglucinol in free solution. This system has been used to study the effects of fungal elicitor on the synthesis of lignin in soybean cells. The inclusion of very low levels of an elicitor fraction from the cell walls of Phytophthora megasperma in the medium in which lignification of the soybean cells occurs suppressed both the accumulation of extracellular lignin and phloroglucinol staining of the cell walls without affecting the levels of bound hydroxycinnamic acids. The activity profiles of phenylalanine ammonia-lyase (EC 4.3.1.5) and isoenzymes of 4-coumarate:CoA ligase (EC 6.2.1.12) were compared in lignifying and elicitor-treated cell cultures as was the activity of chalcone synthase, an enzyme of flavonoid biosynthesis. The measured activities of these enzymes in cell cultures treated with elicitor were considerably lower than in untreated cells.
39 citations
TL;DR: Preparation and assay of chalcone synthase in presence of sodium ascorbate and exclusion of oxygen during some steps gives improved yield and purity of 2 S -naringenin.
37 citations
TL;DR: Observations strengthen the view that the tapetum plays an important role in the regulation of phenylpropanoid metabolism within the loculus of anthers as revealed by sodium dodecyl sulfate disc-gel electrophoresis.
Abstract: Phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) from anthers of the garden tulip “Apeldoorn” have been purified to apparent homogeneity as revealed by sodium dodecyl sulfate disc-gel electrophoresis. Phenylalanine ammonia-lyase was either purified by successive chromatography on Sephacryl S 300 Superfine, HA Ultrogel and on diethylaminoethyl Sephacel or by immunoaffinity chromatography in a single step. Purification of CHS was achieved by chromatography on Sephadex G 200 and on HA Ultrogel followed by chromatofocusing. The purified enzymes were used for the immunization of rabbits. The specificity of the antisera against both PAL and CHS was tested by diverse methods. Antisera against PAL and CHS were employed to detect the localization of the enzymes in cross sections of tulip anthers using an indirect immunofluorometric method. The results show that PAL and CHS are located predominantly in the tapetum cells. These observations strengthen the view that the tapetum plays an important role in the regulation of phenylpropanoid metabolism within the loculus of anthers.
35 citations
TL;DR: In vitro data support the view that the true substrate of CHS in D. carota is 4-coumaroyl-CoA, and it was shown that the inhibition with naringenin was fully uncompetitive.
TL;DR: Chalcone synthase was purified to homogeneity by polyacrylamide gel electrophoresis from cell suspension cultures of carrot in which anthocyanin synthesis was induced by transferring the cells from a medium containing 2,4-dichlorophenoxy-acetic acid to one lacking it.
Abstract: Chalcone synthase was purified to homogeneity by polyacrylamide gel electrophoresis from cell suspension cultures of carrot in which anthocyanin synthesis was induced by transferring the cells from a medium containing 2,4-dichlorophenoxy-acetic acid (2,4-D) to one lacking it. A molecular weight of 80,000-85,000 for the enzyme was determined by gel filtration and disc-gel polyacrylamide electrophoresis, and one of about 40,600 for the subunit by SDS slab-gel electrophoresis. The primary reaction product was chalcone and the pH optimum of the reaction was 8.0. The Km values for 4-coumaroyl-CoA and malonyl-CoA were 5.7 microM and 18 microM, respectively. These properties of carrot chalcone synthase were discussed in comparison to those of that from cell cultures of parsley reported previously. Antiserum against chalcone synthase from carrot was obtained from mice bred under specific pathogen free conditions. Crossreactivity was examined by Western-blotting, and the high specificity of the antiserum against chalcone synthase was demonstrated.
TL;DR: In homogenates of young leaves two different activities of the enzyme could be separated by DEAE-ion exchange chromatography and chromatofocusing and both formed naringenin with [2-14C] malonyl- CoA and 4-coumaroyl-CoA as substrates.
Abstract: Premiere mise en evidence de 2 activites differentes de chalcone synthase et presentation de leurs principales caracteristiques