Sequence Analysis of a “True” Chalcone Synthase ( chs _H1) Oligofamily from hop ( Humulus lupulus L.) and PAP1 Activation of chs _H1 in Heterologous Systems (original) (raw)
Related papers
Plant Physiology and Biochemistry, 1999
Introduction by electroporation of different parsley (Petroselinum crispum) CHS-promoter/ -glucuronidase(GUS)reporter constructs into pea (Pisum sativum L.) protoplasts leads to a high constitutive GUS-expression and to the loss of the light-inducibility seen in the homologous parsley protoplast system. These results indicate that Unit 1 of the parsley CHS-promoter is only partly responsible for the GUS-expression detected. Instead, additional cis-elements, which are located downstream within 100 bp from the transcriptional start site, mediate the de-repression in pea protoplasts. In contrast, in yeast (Saccharomyces cerevisiae) cells, the GUS expression from the heterologous CHS/GUS construct is controlled by elements between Unit 1 and -100 bp. In both pea and yeast cells, transcription factors different from those regulating UV-responsiveness in parsley, are probably mediating the constitutive expression from the heterologous construct. The results with pea protoplasts imply that protoplastation of pea leaf cells itself induces de-repression as a result of stress to the protoplasts. This notion was strengthened by the finding that mRNA levels of the endogenous chalcone synthase were drastically increased as the result of the protoplastation procedure. © 1999 Éditions scientifiques et médicales Elsevier SAS
Chalcone Synthase Promoters in Petunia Are Active in Pigmented and Unpigmented Cell Types
THE PLANT CELL ONLINE, 1990
Chalcone synthase (CHS) catalyzes the first step in the biosynthesis of flavonoids that function in flower pigmentation, protection against stress, and induction of nodulation. The petunia genome contains eight complete chs genes, of which four are differentially expressed in floral tissues and UV-light-induced seedlings. The 5'-flanking regions of these four chs genes were fused to the 8-glucuronidase (GUS) reporter gene and introduced into petunia plants by Agrobacterium-mediated transformation. We show that expression of each construct is identical to the expression of the authentic chs gene, implying that the differences in expression pattern between these chs genes are caused at least in part by their promoters. Histochemical analyses of GUS expression show that chs promoters are not only active in pigmented cell types (epidermal cells of the flower corolla and tube and [sub] epidermal cells of the flower stem) but also in a number of unpigmented cell types (mesophylic cells of the corolla, several cell types in the ovary and the seed coat). Comparison of chs-GUS expression and flavonoid accumulation patterns in anthers suggests that intercellular transport of flavonoids and enzymes occurs in this organ. Analysis of the flavonoids accumulated in tissues from mutant lines shows that only a subset of the genes that control flavonoid biosynthesis in the flower operates in the ovary and seed. This implies that (genetic) control of flavonoid biosynthesis is highly tissue specific.
Plant Cell Reports, 2012
Hop is an important source of secondary metabolites, such as flavonoids. Some of these are pharmacologically active. Nevertheless, the concentration of some classes as flavonoids in wild-type plants is rather low. To enhance the production in hop, it would be interesting to modify the regulation of genes in the flavonoid biosynthetic pathway. For this purpose, the regulatory factor PAP1/AtMYB75 from Arabidopsis thaliana L. was introduced into hop plants cv. Tettnanger by Agrobacterium-mediated genetic transformation. Twenty kanamycinresistant transgenic plants were obtained. It was shown that PAP1/AtMYB75 was stably incorporated and expressed in the hop genome. In comparison to the wild-type plants, the color of female flowers and cones of transgenic plants was reddish to pink. Chemical analysis revealed higher levels of anthocyanins, rutin, isoquercitin, kaempferol-glucoside, kaempferol-glucoside-malonate, desmethylxanthohumol, xanthohumol, a-acids and b-acids in transgenic plants compared to wild-type plants.
Plant Soil and Environment, 2002
The complete sequence hop gene, which corresponds to true chalcone synthase (EC 2.3.1.74), was amplified using a combination of PCR, RT PCR and inverse PCR methods and cloned from Czech Osvald's clone 72. The gene designated chs_H1 was found to be specifically expressed on glandular trichomes, whereas negligible level of specific mRNA was found in leaves. Thus, chs_H1 may co-determine biosynthesis of prenylated chalcones, compounds valuable as anticancer and antiproliferative components of lupulin. It was shown by the comparative analyses and by the structure modelling that the true hop chalcone synthase differs from previously described CHS-like protein, phlorisovalerophenone synthase, which is involved in biosynthesis of bitter acids. Several hop cultivars were analysed for the presence of genes homologous to chs_H1 using chs_H1 cDNA as probe. 2-4 HindIII specific genomic fragments were detected by Southern blots, depending on cultivar. More detailed analysis revealed at least six homologous genes in Osvald's 72 hop, suggesting a great potential of this hop also as a genetic source for modern biotechnology. High level of xanthohumol in some Osvald's 72-derived hybrid cultivars like cv. Sládek, as well as a comparatively high level of prenylated flavonoids in some comprehensive hops, suggest also the presence of additional, regulatory genes co-determining levels of prenylated flavonoids valuable for medicinal hops.
Biochem Biophys Res Commun, 2003
We isolated the chalcone reductase (pl-chr) gene of Pueraria montana var. lobata by using a PCR strategy from cDNA pools of storage roots. A high level of expression of RNA was found in both stems and roots. The genomic Southern blot result suggests that pl-chr exists as a member of a small gene family. By introducing a pl-chr gene under the control of the 35S CaMV promoter into the pink-flowering Xanthi line of Nicotiana tabacum, the flower color was changed from pink to white-to-pink. The contents of anthocyanin in the flowers of the transgenic lines were dramatically decreased by 40%, but the total UV absorption compounds remained unchanged. The production of liquiritigenin in pl-chr overexpressed transgenic tobacco lines was confirmed by HPLC and MS analysis. The introduction of pl-chr gene provides a method to redirect the flavonoid pathway into 5 0-deoxyflavonoid production in non-legume crops, in order to manipulate the phenylpropanoid pathway for isoflavonoid production.
Rostlinna Vyroba
The complete sequence hop gene, which corresponds to true chalcone synthase (EC 2.3.1.74), was amplified using a combination of PCR, RT PCR and inverse PCR methods and cloned from Czech Osvald's clone 72. The gene designated chs_H1 was found to be specifically expressed on glandular trichomes, whereas negligible level of specific mRNA was found in leaves. Thus, chs_H1 may co-determine biosynthesis of prenylated chalcones, compounds valuable as anticancer and antiproliferative components of lupulin. It was shown by the comparative analyses and by the structure modelling that the true hop chalcone synthase differs from previously described CHS-like protein, phlorisovalerophenone synthase, which is involved in biosynthesis of bitter acids. Several hop cultivars were analysed for the presence of genes homologous to chs_H1 using chs_H1 cDNA as probe. 2-4 HindIII specific genomic fragments were detected by Southern blots, depending on cultivar. More detailed analysis revealed at least six homologous genes in Osvald's 72 hop, suggesting a great potential of this hop also as a genetic source for modern biotechnology. High level of xanthohumol in some Osvald's 72-derived hybrid cultivars like cv. Sládek, as well as a comparatively high level of prenylated flavonoids in some comprehensive hops, suggest also the presence of additional, regulatory genes co-determining levels of prenylated flavonoids valuable for medicinal hops.
Plant Cell Reports
The first enzyme in the flavonoid pathway, chalcone synthase, is encoded by a gene (CHS) whose expression is normally under developmental control. In our previous studies, an 896-bp promoter region of a flower-specific CHS gene was isolated from Lilium orential ‘Sorbonne’, and designated as PLoCHS. Here, the PLoCHS promoter was fused to the β-glucuronidase (GUS) gene to characterize its spatial and temporal expression in Petunia hybrida ‘Dreams Midnight’ using an Agrobacterium-mediated leaf disc transformation method. Our results demonstrated that GUS expression was present in flowers, but reduced or absent in the other tissues (leaf and stem) examined. In petals, GUS activity reached its peak at flower developmental stage 4, and decreased at later stages. Deletion analysis indicated that even a 307-bp fragment of the PLoCHS promoter could still direct flower-specific expression. Further deletion of the region from −261 to −72 bp resulted in weak expression in different organs, including flowers, leaves and stems. This evidence combined with prediction of cis-acting elements in the PLoCHS promoter suggests that the TACPyAT box located in this promoter plays a key role in the regulation of organ-specific expression.
Plant molecular biology, 1996
Expression of chalcone synthase (CHS), the first enzyme in the flavonoid branch of the phenylpropanoid biosynthetic pathway in plants, is induced by developmental cues and environmental stimuli. We used plant transformation technology to delineate the functional structure of the French bean CHS15 gene promoter during plant development. In the absence of an efficient transformation procedure for bean, Nicotiana tabacum was used as the model plant. CHS15 promoter activity, evaluated by measurements of beta-D-glucuronidase (GUS) activity, revealed a tissue-specific pattern of expression similar to that reported for CHS genes in bean. GUS activity was observed in flowers and root tips. Floral expression was confined to the pigmented part of petals and was induced in a transient fashion. Fine mapping of promoter cis-elements was accomplished using a set of promoter mutants generated by unidirectional deletions or by site-directed mutagenesis. Maximal floral and root-specific expression w...
Chalcone synthase homologues from Humulus lupulus: some enzymatic properties and expression
Biologia Plantarum, 2006
The enzymatic properties of four chalcone synthase homologues CHS_H1, VPS, CHS 2 and CHS 4 from Humulus lupulus L. were investigated after heterologous expression in Escherichia coli. It was found that both VPS and CHS_H1 can utilize isovaleryl-CoA and isobutyryl-CoA as substrates producing compounds with positions in thin layer chromatography characteristic for phloroisovalerophenone and phloroisobutyrophenone. These reactions are accompanied by the formation of associated byproducts. The formation of naringenin chalcone can be catalyzed primarily by CHS_H1. Comparatively the ability of VPS to perform chalcone synthase reaction is very limited. Since only CHS_H1 has true chalcone synthase activity, this enzyme can be considered a key enzyme in prenylflavonoid biosynthesis. Both CHS 2 and CHS 4 utilize isovaleryl-CoA and isobutyryl-CoA as substrates, but the reactions were prematurely terminated. In comparison with VPS and CHS_H1, the optimum pH of CHS 2 was shifted to lower value. High expression of chalcone synthase-like genes were found in maturating hop cones of cultivars with high bitter acid content (Agnus, Magnum, Target) by Northern and Western blotting using probes specific for vps, chs_H1, chs 4 and polyspecific serum risen against recombinant protein CHS4, respectively. It was also found that these cultivars maintained expression of CHS homologues for a longer period of time during cone development in contrast to timelimited expression of CHS homologues in cultivars with low bitter acids content.