Abstract
Polyclonal antibodies were developed against the flavonoid biosynthetic enzymes, CHS, CHI, F3H, FLS, and LDOX from Arabidopsis thaliana. These antibodies were used to perform the first detailed analysis of coordinate expression of flavonoid metabolism at the protein level. The pattern of flavonoid enzyme expression over the course of seedling development was consistent with previous studies indicating that chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), and flavonol synthase (FLS) are encoded by 'early' genes while leucoanthocyanidin dioxygenase (LDOX) is encoded by a 'late' gene. This sequential expression may underlie the variations in flavonoid end-products produced during this developmental stage, as determined by HPLC analysis, which includes a shift in the ratio of the flavonols, quercetin and kaempferol. Moreover, immunoblot and HPLC analyses revealed that several transparent testa lines blocked at intermediate steps of the flavonoid pathway actually accumulated higher levels of specific flavonoid enzymes and end-products. These results suggest that specific intermediates may act as inducers of flavonoid metabolism.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Acyltransferases / genetics
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Acyltransferases / immunology
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Acyltransferases / metabolism
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Amino Acid Sequence
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Arabidopsis / enzymology*
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Arabidopsis / genetics*
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Arabidopsis / growth & development
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Base Sequence
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Escherichia coli / genetics
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Flavonoids / biosynthesis*
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Gene Expression Regulation, Plant
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Genes, Plant*
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Glycosides / isolation & purification
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Intramolecular Lyases / genetics
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Intramolecular Lyases / immunology
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Intramolecular Lyases / metabolism
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Kaempferols*
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Light
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Mixed Function Oxygenases / genetics
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Mixed Function Oxygenases / immunology
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Mixed Function Oxygenases / metabolism
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Molecular Sequence Data
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Mutation
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Oxidoreductases / genetics
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Oxidoreductases / immunology
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Oxidoreductases / metabolism
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Oxygenases / genetics
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Oxygenases / immunology
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Oxygenases / metabolism
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Plant Proteins*
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Quercetin / analogs & derivatives
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Quercetin / isolation & purification
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Recombinant Proteins / metabolism
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Time Factors
Substances
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Flavonoids
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Glycosides
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Kaempferols
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Plant Proteins
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Recombinant Proteins
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kaempferol
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Quercetin
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Mixed Function Oxygenases
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Oxidoreductases
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Oxygenases
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leucoanthocyanidin dioxygenase
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flavanone 3-dioxygenase
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flavonol synthase
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Acyltransferases
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flavanone synthetase
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Intramolecular Lyases
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chalcone isomerase