High-flavonol tomatoes resulting from the heterologous expression of the maize transcription factor genes LC and C1.

TY - JOUR

T1 - High-flavonol tomatoes resulting from the heterologous expression of the maize transcription factor genes LC and C1.

AU - Bovy, Arnaud

AU - de Vos, Ric

AU - Kemper, Markus J.

AU - Schijlen, Elio

AU - Maria, Almenar Pertejo

AU - Muir, Shelagh

AU - Collins, Geoff

AU - Robinson, Sue

AU - Verhoeyen, Martine

AU - Hughes, Steve

AU - Santos-Buelga, Celestino

AU - van Tunen, Arjen

PY - 2002

Y1 - 2002

N2 - Flavonoids are a group of polyphenolic plant secondary metabolites important for plant biology and human nutrition. In particular flavonols are potent antioxidants, and their dietary intake is correlated with a reduced risk of cardiovascular diseases. Tomato fruit contain only in their peel small amounts of flavonoids, mainly naringenin chalcone and the flavonol rutin, a quercetin glycoside. To increase flavonoid levels in tomato, we expressed the maize transcription factor genes LC and C1 in the fruit of genetically modified tomato plants. Expression of both genes was required and sufficient to upregulate the flavonoid pathway in tomato fruit flesh, a tissue that normally does not produce any flavonoids. These fruit accumulated high levels of the flavonol kaempferol and, to a lesser extent, the flavanone naringenin in their flesh. All flavonoids detected were present as glycosides. Anthocyanins, previously reported to accumulate upon LC expression in several plant species, were present in LC/C1 tomato leaves but could not be detected in ripe LC/C1 fruit. RNA expression analysis of ripening fruit revealed that, with the exception of chalcone isomerase, all of the structural genes required for the production of kaempferol-type flavonols and pelargonidin-type anthocyanins were induced strongly by the LC/C1 transcription factors. Expression of the genes encoding flavanone-3'-hydroxylase and flavanone-3'5'-hydroxylase, which are required for the modification of B-ring hydroxylation patterns, was not affected by LC/C1. Comparison of flavonoid profiles and gene expression data between tomato leaves and fruit indicates that the absence of anthocyanins in LC/C1 fruit is attributable primarily to an insufficient expression of the gene encoding flavanone-3'5'-hydroxylase, in combination with a strong preference of the tomato dihydroflavonol reductase enzyme to use the flavanone-3'5'-hydroxylase reaction product dihydromyricetin as a substrate.

AB - Flavonoids are a group of polyphenolic plant secondary metabolites important for plant biology and human nutrition. In particular flavonols are potent antioxidants, and their dietary intake is correlated with a reduced risk of cardiovascular diseases. Tomato fruit contain only in their peel small amounts of flavonoids, mainly naringenin chalcone and the flavonol rutin, a quercetin glycoside. To increase flavonoid levels in tomato, we expressed the maize transcription factor genes LC and C1 in the fruit of genetically modified tomato plants. Expression of both genes was required and sufficient to upregulate the flavonoid pathway in tomato fruit flesh, a tissue that normally does not produce any flavonoids. These fruit accumulated high levels of the flavonol kaempferol and, to a lesser extent, the flavanone naringenin in their flesh. All flavonoids detected were present as glycosides. Anthocyanins, previously reported to accumulate upon LC expression in several plant species, were present in LC/C1 tomato leaves but could not be detected in ripe LC/C1 fruit. RNA expression analysis of ripening fruit revealed that, with the exception of chalcone isomerase, all of the structural genes required for the production of kaempferol-type flavonols and pelargonidin-type anthocyanins were induced strongly by the LC/C1 transcription factors. Expression of the genes encoding flavanone-3'-hydroxylase and flavanone-3'5'-hydroxylase, which are required for the modification of B-ring hydroxylation patterns, was not affected by LC/C1. Comparison of flavonoid profiles and gene expression data between tomato leaves and fruit indicates that the absence of anthocyanins in LC/C1 fruit is attributable primarily to an insufficient expression of the gene encoding flavanone-3'5'-hydroxylase, in combination with a strong preference of the tomato dihydroflavonol reductase enzyme to use the flavanone-3'5'-hydroxylase reaction product dihydromyricetin as a substrate.

KW - Phenotype

KW - Light

KW - Molecular Structure

KW - Transcription Factors/genetics/metabolism

KW - Alcohol Oxidoreductases/genetics/metabolism

KW - Anthocyanins/biosynthesis/chemistry

KW - Flavanones

KW - Flavonoids/biosynthesis/chemistry

KW - Fruit/metabolism

KW - Gene Expression Regulation, Plant

KW - Hydroxylation

KW - Kaempferols

KW - Lycopersicon esculentum/chemistry/genetics/metabolism

KW - Mixed Function Oxygenases/genetics/metabolism

KW - Pigments, Biological/biosynthesis/chemistry

KW - Plant Leaves/metabolism

KW - Plants, Genetically Modified

KW - Quercetin/biosynthesis/chemistry

KW - Zea mays/genetics

KW - Phenotype

KW - Light

KW - Molecular Structure

KW - Transcription Factors/genetics/metabolism

KW - Alcohol Oxidoreductases/genetics/metabolism

KW - Anthocyanins/biosynthesis/chemistry

KW - Flavanones

KW - Flavonoids/biosynthesis/chemistry

KW - Fruit/metabolism

KW - Gene Expression Regulation, Plant

KW - Hydroxylation

KW - Kaempferols

KW - Lycopersicon esculentum/chemistry/genetics/metabolism

KW - Mixed Function Oxygenases/genetics/metabolism

KW - Pigments, Biological/biosynthesis/chemistry

KW - Plant Leaves/metabolism

KW - Plants, Genetically Modified

KW - Quercetin/biosynthesis/chemistry

KW - Zea mays/genetics

M3 - SCORING: Journal article

VL - 14

SP - 2509

EP - 2526

JO - PLANT CELL

JF - PLANT CELL

SN - 1040-4651

IS - 10

M1 - 10

ER -