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Query: UNIPROT:P06889 (Mol)
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Phenylalanine ammonia-lyase and chalcone synthase catalyze the first reaction of phenylpropanoid biosynthesis and the first reaction of a branch pathway specific for flavonoid-isoflavonoid biosynthesis, respectively. These enzymes are key control elements in the synthesis of kievitone, phaseollin, and related isoflavonoid-derived phytoalexins. RNA blot hybridization with 32P-labeled cDNA sequences was used to demonstrate marked accumulation of phenylalanine ammonia-lyase and chalcone synthase mRNAs in excision-wounded hypocotyls of Phaseolus vulgaris L. (dwarf French bean) and during race-cultivar-specific interactions between hypocotyls of P. vulgaris and the partially biotrophic fungus Colletotrichum lindemuthianum, the causal agent of anthracnose. In an incompatible interaction (host resistant), early concomitant accumulation of phenylalanine ammonia-lyase and chalcone synthase mRNAs, localized mainly but not entirely in tissue adjacent to the site of infection, was observed prior to the onset of phytoalexin accumulation and expression of localized, hypersensitive resistance. In contrast, in a compatible interaction (host susceptible) there was no early accumulation of these transcripts; instead, there was a delayed widespread response associated with phytoalexin accumulation during attempted lesion limitation. Two-dimensional gel electrophoresis of [35S]methionine-labeled polypeptides synthesized in vitro by translation of isolated polysomal RNA demonstrated stimulation of the synthesis of characteristic sets of phenylalanine ammonia-lyase and chalcone synthase isopolypeptides in directly infected tissue and distant, hitherto uninfected tissue in both compatible and incompatible interactions. Our data show that specific accumulation of plant defense gene transcripts is a key early component in the sequence of events leading to expression of defense responses in wounded tissue and in infected tissue during race-cultivar-specific interactions and that an elicitation signal is transmitted intercellularly in response to infection.
Mol Cell Biol 1986 May
PMID:Differential accumulation of plant defense gene transcripts in a compatible and an incompatible plant-pathogen interaction. 378 74

A nuclear factor (SBF-1) has previously been identified in Phaseolus vulgaris L. (bean) suspension cell nuclear extracts that binds in vitro to three DNase I-footprinted elements (SBF-1 boxes I, II, and III, 5' to 3') in the 5' region of the bean CHS15 (chalcone synthase) gene promoter. To define the functional role of the three SBF-1 boxes in development, we examined transgenic tobacco plants carrying a series of nested CHS15 promoter-beta-glucuronidase (GUS) fusions for GUS activity by histochemical staining. We show that the CHS15 promoter deleted to position -173 and lacking all three SBF-1 boxes directs the same qualitative pattern of expression in initiating lateral roots and in developing seeds as the full length promoter (-326). Thus, activation of expression in these organs is mediated by sequence elements located downstream of the three SBF-1 boxes. However, specific deletions within the -326 to -173 region modulate expression. Thus, deletion of box II abolishes GUS activity in initiating lateral roots. Further deletion of box III fails to restore expression but subsequent deletion of an additional 43 bp to position -173 re-establishes expression. We show that sequence-specific DNA-binding activities consistent with these results are present in nuclear extracts of bean roots and seeds. These studies reveal cis elements within the CHS15 promoter, and potential trans factors, that permit organ- and tissue-specific developmental patterns of regulation to be combined with a flexible response to environmental cues.
Plant Mol Biol 1995 Sep
PMID:Cis elements and potential trans-acting factors for the developmental regulation of the Phaseolus vulgaris CHS15 promoter. 754 34

Chalcone synthase (CHS; EC 2.3.1.74), the first committed enzyme of the multibranched pathway of flavonoid/isoflavonoid biosynthesis is encoded by a multigene family in soybean, (Glycine max L. Merrill). Our results suggest that this gene family comprises at least seven members, some of which are clustered. We have identified four chs clusters in the allo-tetraploid G. max genome and chs5, a newly characterized member of the chs gene family is present in two of them. We describe the complete nucleotide sequence of chs5, the identification of its immediate neighbors and the organization of the four hitherto identified chs clusters in the Gm genome.
Plant Mol Biol 1995 Oct
PMID:Organization of soybean chalcone synthase gene clusters and characterization of a new member of the family. 757 72

The expression of chalcone synthase (CHS) genes, which encode the first enzyme of the flavonoid pathway, is under developmental control as well as affected by external stimuli such as light. Varying fragments of the 1 kb upstream region of the CHS1 gene from white mustard (Sinapis alba L.) were fused to the GUS-coding region, and the light-regulated expression of these constructs was analysed in transgenic Arabidopsis and tobacco plants. Studies performed with Arabidopsis seedlings indicate the presence of two elements within the CHS1 promoter mediating light responses via different photoreceptors. One element, located about 150 bp upstream of the transcription start site, is homologous to Unit 1 of the parsley CHS gene, the second, far more upstream element carries sequences similar to Unit 2 of the same gene. Detailed studies on Unit 1-driven expression indicate that this element transfers the expression characteristics of the original gene to both Arabidopsis and tobacco. Although the expression characteristics of Unit 1 are indistinguishable from those of the full-length promoter within the same species, we observed differences in mustard CHS promoter regulation between Arabidopsis and tobacco plants transgenic for the identical construct. The difference in photoreceptor usage by the same promoter element in different transgenic species (Unit 1 from mustard in Arabidopsis vs. tobacco) was also observed for different but homologous promoter elements in the same transgenic species (Unit 1 from mustard and parsley in tobacco). We therefore conclude that the same promoter and even the same promoter element (Unit 1) can mediate different spatial patterns of expression and modes of light regulation in different transgenic species.
Plant Mol Biol 1995 May
PMID:Promoter elements of the mustard CHS1 gene are sufficient for light regulation in transgenic plants. 759 8

In the ornamental cut flower plant Gerbera hybrida the spatial distribution of regulatory molecules characteristic of differentiation of the composite inflorescence is visualized as the various patterns of anthocyanin pigmentation of different varieties. In order to identify genes that the plant can regulate according to these anatomical patterns, we have analysed gene expression affecting two enzymatic steps, chalcone synthase (CHS) and dihydroflavonol-4-reductase (DFR), in five gerbera varieties with spatially restricted anthocyanin pigmentation patterns. The dfr expression profiles vary at the levels of floral organ, flower type and region within corolla during inflorescence development according to the anthocyanin pigmentation of the cultivars. In contrast, chs expression, although regulated in a tissue-specific manner during inflorescence development, varies only occasionally. The variation in the dfr expression profiles between the varieties reveals spatially specific gene regulation that senses the differentiation events characteristic of the composite inflorescence.
Plant Mol Biol 1995 Aug
PMID:Gerbera hybrida (Asteraceae) imposes regulation at several anatomical levels during inflorescence development on the gene for dihydroflavonol-4-reductase. 764 Mar 64

Cell suspension cultures of Ruta graveolens L. produce a variety of acridone alkaloids, and the accumulation can be stimulated by the addition of fungal elicitors. Acridone synthase, the enzyme catalyzing the synthesis of 1,3-dihydroxy-N-methylacridone from N-methylanthraniloyl-CoA and malonyl-CoA, had been isolated from these cells, and the partial enzyme polypeptide sequence, elucidated from six tryptic fragments, revealed homology to heterologous chalcone synthases. Poly(A)+ RNA was isolated from Ruta cells that had been treated for 6 h with a crude cell wall elicitor from Phytophthora megasperma f. sp. glycinea, and a cDNA library was constructed in lambda 2AP. Clones harboring acridone synthase cDNA were isolated from the library by screening with a synthetic oligonucleotide probe complementary to a short stretch of sequence of the enzyme peptide with negligible homology to chalcone synthases. The identity of the clones was substantiated by DNA sequencing and by recognition of five additional peptides, determined previously from tryptic acridone synthase digests, in the translated sequence. An insert of roughly 1.4 kb encoded the complete acridone synthase, and alignments at both DNA and protein levels corroborated the high degree of homology to chalcone synthases. Expression of the enzyme in vector pET-11c in the Escherichia coli pLysS host strain proved the identity of the cloned cDNA. The heterologous enzyme in the crude E. coli extract exhibit high acridone but no chalcone synthase activity. The results were fully supported by northern blot hybridizations which revealed that the specific transcript abundance did not increase but rather decreased upon white light irradiation of cultured Ruta graveolens L. cells, a condition that commonly induces the abundance of chalcone synthase transcripts.
Plant Mol Biol 1995 Feb
PMID:Molecular cloning and heterologous expression of acridone synthase from elicited Ruta graveolens L. cell suspension cultures. 772 46

Recent studies on chalcone synthase (CHS) and the related stilbene synthase (STS) suggest that the structure of chs-like genes in plants has evolved into different forms, whose members have both different regulation and capacity to code for different but related enzymatic activities. We have studied the diversity of chs-like genes by analysing the structure, expression patterns and catalytic properties of the corresponding enzymes of three genes that are active during corolla development in Gerbera hybrida. The expression patterns demonstrate that chs-like genes are representatives of three distinct genetic programmes that are active during organ differentiation in gerbera. Gchs1 and gchs3 code for typical CHS enzymes, and their gene expression pattern temporally correlates with flavonol (gchs1, gchs3) and anthocyanin (gchs1) synthesis during corolla development. Gchs2 is different. The expression pattern does not correlate with the pigmentation pattern, the amino acid sequence deviates considerably from the consensus of typical CHSs, and the catalytic properties are different. The data indicate that it represents a new member in the large superfamily of chs and chs-related genes.
Plant Mol Biol 1995 Apr
PMID:Chalcone synthase-like genes active during corolla development are differentially expressed and encode enzymes with different catalytic properties in Gerbera hybrida (Asteraceae). 778 87

Two-dimensional gel electrophoresis of pea root and root hair proteins revealed the existence of at least 10 proteins present at elevated levels in root hairs. One of these, named RH2, was isolated and a partial amino acid sequence was determined from two tryptic peptides. Using this sequence information oligonucleotides were designed to isolate by PCR an RH2 cDNA clone. In situ hybridization studies with this cDNA clone showed that rh2 is not only expressed in root hairs, but also in root epidermal cells lacking these tubular outgrowths. During post-embryonic development the gene is switched on after the transition of protoderm into epidermis and since rh2 is already expressed in a globular pea embryo in the protoderm at the side attached to the suspensor, we conclude that the expression of rh2 is developmentally regulated. At the amino acid level RH2 is 95% homologous to the pea PR protein I49a. These gene encoding I49a is induced in pea pods upon inoculation with the pathogen Fusarium solani [12]. We postulate that rh2 contributes to a constitutive defence barrier in the root epidermis. A similar role has been proposed for chalcone synthase (CHS) and chitinase, pathogenesis-related protein that are also constitutively present in certain epidermal tissues.
Plant Mol Biol 1994 Oct
PMID:The root epidermis-specific pea gene RH2 is homologous to a pathogenesis-related gene. 794 84

Phenylalanine ammonia-lyase (PAL) is the first enzyme of phenylpropanoid biosynthesis involved in the synthesis of a multiplicity of plant natural products. We have isolated and characterized a nearly full-length cDNA clone (pmPAL-1) corresponding to a melon fruit (Cucumis melo L. var. reticulatus) gene coding for a protein which is highly similar to PAL from other plants. Melon fruit PAL is transcriptionally induced both in response to fruit ripening and wounding. PAL gene expression follows the kinetics of expression of the ethylene biosynthetic genes during fruit development. In contrast, ethylene biosynthetic genes show different induction kinetics compared to PAL expression in response to wounding. Similar results have been found for two other genes coding for enzymes involved in flavonoid biosynthesis (chalcone synthase, CHS; chalcone isomerase, CHI). Our results imply that regulation of defense gene expression in melon is a co-ordinated process in response to both ethylene and an ethylene-independent wound signal.
Plant Mol Biol 1994 Oct
PMID:A phenylalanine ammonia-lyase gene from melon fruit: cDNA cloning, sequence and expression in response to development and wounding. 794 94

The development of plant in vitro transcription systems transcribing faithfully and efficiently from a broad range of plant nuclear promoters has remained a challenge. We examined the nucleotide sequence requirements for faithful and efficient transcription in a wheat germ chromatin extract (Yamazaki et al., Plant Mol Biol Rep 8: 114-123). The wheat germ chromatin extract was tested with a series of chimeric promoter constructs containing plant promoter sequences upstream from the TATA box, TATA boxes, and cap-site sequences (from -10 to +14, relative to the major in vivo initiation site) in different combinations. The plant extract transcribed faithfully from several chimeric promoters containing the capsite sequence of the parsley chalcone synthase promoter. The transcription was sensitive to the RNA polymerase II-specific inhibitor alpha-amanitin and was only dependent on the chalcone synthase cap-site sequence which therefore fulfils the operational criteria for a plant initiator element. Mutations of the putative chalcone synthase initiator element defined a core sequence '5'TAACAAC' around the initiation site that was necessary for efficient transcription in vitro. In contrast to the extract, purified wheat germ RNA polymerase II showed no preference for transcription from the major chalcone synthase in vivo initiation site.
Plant Mol Biol 1994 Apr
PMID:Initiator-dependent transcription in vitro by a wheat germ chromatin extract. 800 92


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