The Antioxidant Cyclic 3-Hydroxymelatonin Promotes the Growth and Flowering of <i>Arabidopsis thaliana</i>
In plants, melatonin is metabolized into several compounds, including the potent antioxidant cyclic 3-hydroxymelatonin (3-OHM). Melatonin 3-hydroxylase (M3H), a member of the 2-oxo-glutarate-dependent enzyme family, is responsible for 3-OHM biosynthesis. Although rice <i>M3H</i> has been...
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MDPI AG
2022-06-01
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| Series: | Antioxidants |
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| Online Access: | https://www.mdpi.com/2076-3921/11/6/1157 |
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| author | Hyoung Yool Lee Kyoungwhan Back |
| author_facet | Hyoung Yool Lee Kyoungwhan Back |
| author_sort | Hyoung Yool Lee |
| collection | DOAJ |
| description | In plants, melatonin is metabolized into several compounds, including the potent antioxidant cyclic 3-hydroxymelatonin (3-OHM). Melatonin 3-hydroxylase (M3H), a member of the 2-oxo-glutarate-dependent enzyme family, is responsible for 3-OHM biosynthesis. Although rice <i>M3H</i> has been cloned, its roles are unclear, and no homologs in other plant species have been characterized. Here, we cloned and characterized <i>Arabidopsis thaliana M3H</i> (<i>AtM3H</i>). The purified recombinant AtM3H exhibited <i>K</i><sub>m</sub> and <i>V</i><sub>max</sub> values of 100 μM and 20.7 nmol/min/mg protein, respectively. M3H was localized to the cytoplasm, and its expression peaked at night. Based on a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, 3-OHM exhibited 15-fold higher antioxidant activity than melatonin. An Arabidopsis <i>M3H</i> knockout mutant (<i>m3h</i>) produced less 3-OHM than the wildtype (WT), thus reducing antioxidant activity and biomass and delaying flowering. These defects were caused by reduced expression of <i>FLOWERING LOCUS T</i> (<i>FT</i>) and gibberellin-related genes, which are responsible for flowering and growth. Exogenous 3-OHM, but not exogenous melatonin, induced <i>FT</i> expression. The peak of <i>M3H</i> expression at night matched the <i>FT</i> expression pattern. The WT and <i>m3h</i> exhibited similar responses to salt stress and pathogens. Collectively, our findings indicate that 3-OHM promotes growth and flowering in <i>Arabidopsis</i>. |
| first_indexed | 2024-03-10T00:33:17Z |
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| issn | 2076-3921 |
| language | English |
| last_indexed | 2024-03-10T00:33:17Z |
| publishDate | 2022-06-01 |
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| series | Antioxidants |
| spelling | doaj.art-3f7dd2a678284f8e969db8e5d8718beb2023-11-23T15:20:34ZengMDPI AGAntioxidants2076-39212022-06-01116115710.3390/antiox11061157The Antioxidant Cyclic 3-Hydroxymelatonin Promotes the Growth and Flowering of <i>Arabidopsis thaliana</i>Hyoung Yool Lee0Kyoungwhan Back1Department of Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, KoreaDepartment of Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, KoreaIn plants, melatonin is metabolized into several compounds, including the potent antioxidant cyclic 3-hydroxymelatonin (3-OHM). Melatonin 3-hydroxylase (M3H), a member of the 2-oxo-glutarate-dependent enzyme family, is responsible for 3-OHM biosynthesis. Although rice <i>M3H</i> has been cloned, its roles are unclear, and no homologs in other plant species have been characterized. Here, we cloned and characterized <i>Arabidopsis thaliana M3H</i> (<i>AtM3H</i>). The purified recombinant AtM3H exhibited <i>K</i><sub>m</sub> and <i>V</i><sub>max</sub> values of 100 μM and 20.7 nmol/min/mg protein, respectively. M3H was localized to the cytoplasm, and its expression peaked at night. Based on a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, 3-OHM exhibited 15-fold higher antioxidant activity than melatonin. An Arabidopsis <i>M3H</i> knockout mutant (<i>m3h</i>) produced less 3-OHM than the wildtype (WT), thus reducing antioxidant activity and biomass and delaying flowering. These defects were caused by reduced expression of <i>FLOWERING LOCUS T</i> (<i>FT</i>) and gibberellin-related genes, which are responsible for flowering and growth. Exogenous 3-OHM, but not exogenous melatonin, induced <i>FT</i> expression. The peak of <i>M3H</i> expression at night matched the <i>FT</i> expression pattern. The WT and <i>m3h</i> exhibited similar responses to salt stress and pathogens. Collectively, our findings indicate that 3-OHM promotes growth and flowering in <i>Arabidopsis</i>.https://www.mdpi.com/2076-3921/11/6/1157antioxidantcyclic 3-hydroxymelatonin<i>Escherichia coli</i> expression<i>FLOWERING LOCUS T</i>gibberellinmelatonin |
| spellingShingle | Hyoung Yool Lee Kyoungwhan Back The Antioxidant Cyclic 3-Hydroxymelatonin Promotes the Growth and Flowering of <i>Arabidopsis thaliana</i> Antioxidants antioxidant cyclic 3-hydroxymelatonin <i>Escherichia coli</i> expression <i>FLOWERING LOCUS T</i> gibberellin melatonin |
| title | The Antioxidant Cyclic 3-Hydroxymelatonin Promotes the Growth and Flowering of <i>Arabidopsis thaliana</i> |
| title_full | The Antioxidant Cyclic 3-Hydroxymelatonin Promotes the Growth and Flowering of <i>Arabidopsis thaliana</i> |
| title_fullStr | The Antioxidant Cyclic 3-Hydroxymelatonin Promotes the Growth and Flowering of <i>Arabidopsis thaliana</i> |
| title_full_unstemmed | The Antioxidant Cyclic 3-Hydroxymelatonin Promotes the Growth and Flowering of <i>Arabidopsis thaliana</i> |
| title_short | The Antioxidant Cyclic 3-Hydroxymelatonin Promotes the Growth and Flowering of <i>Arabidopsis thaliana</i> |
| title_sort | antioxidant cyclic 3 hydroxymelatonin promotes the growth and flowering of i arabidopsis thaliana i |
| topic | antioxidant cyclic 3-hydroxymelatonin <i>Escherichia coli</i> expression <i>FLOWERING LOCUS T</i> gibberellin melatonin |
| url | https://www.mdpi.com/2076-3921/11/6/1157 |
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