Flavonoid biosynthesis requires the activities of several enzymes, which form weakly-bound, ordered protein complexes termed metabolons. To decipher flux regulation in the flavonoid biosynthetic pathway of chrysanthemum (
Chrysanthemum morifolium Ramat), we suppressed the gene-encoding dihydroflavonol 4-reductase (DFR) through RNA interference (RNAi)-mediated post-transcriptional
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Flavonoid biosynthesis requires the activities of several enzymes, which form weakly-bound, ordered protein complexes termed metabolons. To decipher flux regulation in the flavonoid biosynthetic pathway of chrysanthemum (
Chrysanthemum morifolium Ramat), we suppressed the gene-encoding dihydroflavonol 4-reductase (DFR) through RNA interference (RNAi)-mediated post-transcriptional gene silencing under a floral-specific promoter. Transgenic
CmDFR-RNAi chrysanthemum plants were obtained by
Agrobacterium-mediated transformation. Genomic PCR analysis of
CmDFR-RNAi chrysanthemums propagated by several rounds of stem cuttings verified stable transgene integration into the genome.
CmDFR mRNA levels were reduced by 60–80% in
CmDFR-RNAi lines compared to those in wild-type (WT) plants in ray florets, but not leaves. Additionally, transcript levels of flavonoid biosynthetic genes were highly upregulated in ray florets of
CmDFR-RNAi chrysanthemum relative to those in WT plants, while transcript levels in leaves were similar to WT. Total flavonoid contents were high in ray florets of
CmDFR-RNAi chrysanthemums, but flavonoid contents of leaves were similar to WT, consistent with transcript levels of flavonoid biosynthetic genes. Ray florets of
CmDFR-RNAi chrysanthemums exhibited stronger antioxidant capacity than those of WT plants. We propose that post-transcriptional silencing of
CmDFR in ray florets modifies metabolic flux, resulting in enhanced flavonoid content and antioxidant activity.
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