Transcriptional activation of anthocyanin structural genes in Torenia ‘Kauai Rose’ via overexpression of anthocyanin regulatory transcription factors
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This study was conducted to examine the role of the transcription factors (TFs), RsMYB1 and mPAP1 together with B-Peru (mPAP1 + B-Peru), in regulating anthocyanin biosynthesis in the ornamental torenia (Torenia fournieri) cultivar Kauai Rose using Agrobacterium-mediated transformation. Expression levels of RsMYB1 were the highest in the lines RS5 and RS3, followed by RS4, RS2, and RS1, while transcript levels of mPAP1 + B-Peru increased in the order of PB-6 > PB-5 > PB-7 > PB-8 > PB-2. Moreover, transcript levels of the anthocyanin structural genes in transgenic lines were significantly higher than those in wild-type (WT) plants. Anthocyanin structural gene expression was specifically altered by TF overexpression: the highest expression of anthocyanidin synthase (ANS) was observed in transgenic lines with RsMYB1, while expression of dihydroflavonol-4-reductase (DFR) was the highest in lines with mPAP1 + B-Peru. We expect that enhanced expression of these anthocyanin structural genes will improve anthocyanin content in the flowers of transgenic torenia. Moreover, these results indicate that RsMYB1 and mPAP1 + B-Peru can be exploited as anthocyanin regulatory TFs to enhance anthocyanin content in other horticultural plants.
KeywordsFlower color Genetic transformation Ornamental plant Quantitative real-time polymerase chain reaction (qRT-PCR) Anthocyanin RsMYB1 mPAP1 B-Peru
We wish to acknowledge Dr. Sun-Hung Lim (RDA, South Korea) for providing the plasmid constructs.
AHN and XJ designed the study, conducted the experiments, and wrote the manuscript. CKK supervised experiments at all stages and performed critical revisions of the manuscript. All authors read and approved the final manuscript.
Compliance with ethical standards
Conflict of interest
There are no conflicts of interest.
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