Increased Flavonol Levels in Tobacco Expressing <i>AcFLS</i> Affect Flower Color and Root Growth
The onion (<i>Allium cepa</i> L.) <i>flavonol synthase</i> (<i>AcFLS-HRB</i>) gene, encoding an enzyme responsible for flavonol biosynthesis in yellow onion, was recently identified and enzymatically characterized. Here, we performed an in vivo feeding assay invol...
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MDPI AG
2020-02-01
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| Series: | International Journal of Molecular Sciences |
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| author | Sangkyu Park Da-Hye Kim Ju-Hee Yang Jong-Yeol Lee Sun-Hyung Lim |
| author_facet | Sangkyu Park Da-Hye Kim Ju-Hee Yang Jong-Yeol Lee Sun-Hyung Lim |
| author_sort | Sangkyu Park |
| collection | DOAJ |
| description | The onion (<i>Allium cepa</i> L.) <i>flavonol synthase</i> (<i>AcFLS-HRB</i>) gene, encoding an enzyme responsible for flavonol biosynthesis in yellow onion, was recently identified and enzymatically characterized. Here, we performed an in vivo feeding assay involving bacterial expression of AcFLS-HRB and observed that it exhibited both flavanone 3-hydroxylase (F3H) and FLS activity. Transgenic tobacco (<i>Nicotiana tabacum</i>) expressing <i>AcFLS-HRB</i> produced lighter-pink flowers compared to wild-type plants. In transgenic petals, <i>AcFLS-HRB</i> was highly expressed at the mRNA and protein levels, and most AcFLS-HRB protein accumulated in the insoluble microsomal fractions. High-performance liquid chromatography (HPLC) analysis showed that flavonol levels increased but anthocyanin levels decreased in transgenic petals, indicating that <i>AcFLS-HRB</i> is a functional gene in planta. Gene expression analysis showed the reduced transcript levels of general phenylpropanoid biosynthetic genes and flavonoid biosynthetic genes in <i>AcFLS-HRB</i> overexpressed tobacco petals. Additionally, transgenic tobacco plants at the seedling stages showed increased primary root and root hair length and enhanced quercetin signals in roots. Exogenous supplementation with quercetin 3-<i>O</i>-rutinoside (rutin) led to the same phenotypic changes in root growth, suggesting that rutin is the causal compound that promotes root growth in tobacco. Therefore, augmenting flavonol levels affects both flower color and root growth in tobacco. |
| first_indexed | 2024-04-13T09:29:25Z |
| format | Article |
| id | doaj.art-cda6dd49cf7249618d7dfac035a89b16 |
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| language | English |
| last_indexed | 2024-04-13T09:29:25Z |
| publishDate | 2020-02-01 |
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| series | International Journal of Molecular Sciences |
| spelling | doaj.art-cda6dd49cf7249618d7dfac035a89b162022-12-22T02:52:19ZengMDPI AGInternational Journal of Molecular Sciences1422-00672020-02-01213101110.3390/ijms21031011ijms21031011Increased Flavonol Levels in Tobacco Expressing <i>AcFLS</i> Affect Flower Color and Root GrowthSangkyu Park0Da-Hye Kim1Ju-Hee Yang2Jong-Yeol Lee3Sun-Hyung Lim4National Institute of Agricultural Sciences, Rural Development Administration, JeonJu 54874, KoreaNational Institute of Agricultural Sciences, Rural Development Administration, JeonJu 54874, KoreaNational Institute of Agricultural Sciences, Rural Development Administration, JeonJu 54874, KoreaNational Institute of Agricultural Sciences, Rural Development Administration, JeonJu 54874, KoreaNational Institute of Agricultural Sciences, Rural Development Administration, JeonJu 54874, KoreaThe onion (<i>Allium cepa</i> L.) <i>flavonol synthase</i> (<i>AcFLS-HRB</i>) gene, encoding an enzyme responsible for flavonol biosynthesis in yellow onion, was recently identified and enzymatically characterized. Here, we performed an in vivo feeding assay involving bacterial expression of AcFLS-HRB and observed that it exhibited both flavanone 3-hydroxylase (F3H) and FLS activity. Transgenic tobacco (<i>Nicotiana tabacum</i>) expressing <i>AcFLS-HRB</i> produced lighter-pink flowers compared to wild-type plants. In transgenic petals, <i>AcFLS-HRB</i> was highly expressed at the mRNA and protein levels, and most AcFLS-HRB protein accumulated in the insoluble microsomal fractions. High-performance liquid chromatography (HPLC) analysis showed that flavonol levels increased but anthocyanin levels decreased in transgenic petals, indicating that <i>AcFLS-HRB</i> is a functional gene in planta. Gene expression analysis showed the reduced transcript levels of general phenylpropanoid biosynthetic genes and flavonoid biosynthetic genes in <i>AcFLS-HRB</i> overexpressed tobacco petals. Additionally, transgenic tobacco plants at the seedling stages showed increased primary root and root hair length and enhanced quercetin signals in roots. Exogenous supplementation with quercetin 3-<i>O</i>-rutinoside (rutin) led to the same phenotypic changes in root growth, suggesting that rutin is the causal compound that promotes root growth in tobacco. Therefore, augmenting flavonol levels affects both flower color and root growth in tobacco.https://www.mdpi.com/1422-0067/21/3/1011<i>allium cepa</i>anthocyaninflavonoidflavonolflavonol synthaseflower colorroot growth |
| spellingShingle | Sangkyu Park Da-Hye Kim Ju-Hee Yang Jong-Yeol Lee Sun-Hyung Lim Increased Flavonol Levels in Tobacco Expressing <i>AcFLS</i> Affect Flower Color and Root Growth International Journal of Molecular Sciences <i>allium cepa</i> anthocyanin flavonoid flavonol flavonol synthase flower color root growth |
| title | Increased Flavonol Levels in Tobacco Expressing <i>AcFLS</i> Affect Flower Color and Root Growth |
| title_full | Increased Flavonol Levels in Tobacco Expressing <i>AcFLS</i> Affect Flower Color and Root Growth |
| title_fullStr | Increased Flavonol Levels in Tobacco Expressing <i>AcFLS</i> Affect Flower Color and Root Growth |
| title_full_unstemmed | Increased Flavonol Levels in Tobacco Expressing <i>AcFLS</i> Affect Flower Color and Root Growth |
| title_short | Increased Flavonol Levels in Tobacco Expressing <i>AcFLS</i> Affect Flower Color and Root Growth |
| title_sort | increased flavonol levels in tobacco expressing i acfls i affect flower color and root growth |
| topic | <i>allium cepa</i> anthocyanin flavonoid flavonol flavonol synthase flower color root growth |
| url | https://www.mdpi.com/1422-0067/21/3/1011 |
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