An LcMYB111-LcHY5 Module Differentially Activates an <i>LcFLS</i> Promoter in Different Litchi Cultivars
Flavonol synthase (FLS) is the crucial enzyme of the flavonol biosynthetic pathways, and its expression is tightly regulated in plants. In our previous study, two alleles of <i>LcFLS,</i> <i>LcFLS-A</i> and <i>LcFLS-B</i>, have been identified in litchi, with extr...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-11-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/23/16817 |
| Summary: | Flavonol synthase (FLS) is the crucial enzyme of the flavonol biosynthetic pathways, and its expression is tightly regulated in plants. In our previous study, two alleles of <i>LcFLS,</i> <i>LcFLS-A</i> and <i>LcFLS-B</i>, have been identified in litchi, with extremely early-maturing (EEM) cultivars only harboring <i>LcFLS-A</i>, while middle-to-late-maturing (MLM) cultivars only harbor <i>LcFLS-B</i>. Here, we overexpressed both <i>LcFLS</i> alleles in tobacco, and transgenic tobacco produced lighter-pink flowers and showed increased flavonol levels while it decreased anthocyanin levels compared to WT. Two allelic promoters of <i>LcFLS</i> were identified, with EEM cultivars only harboring proLcFLS-A, while MLM cultivars only harbor proLcFLS-B. One positive and three negative R2R3-MYB transcription regulators of <i>LcFLS</i> expression were identified, among which only positive regulator <i>LcMYB111</i> showed a consistent expression pattern with <i>LcFLS</i>, which both have higher expression in EEM than that of MLM cultivars. LcMYB111 were further confirmed to specifically activate proLcFLS-A with MYB-binding element (MBE) while being unable to activate proLcFLS-B with mutated MBE (MBEm). LcHY5 were also identified and can interact with LcMYB111 to promote <i>LcFLS</i> expression. Our study elucidates the function of <i>LcFLS</i> and its differential regulation in different litchi cultivars for the first time. |
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| ISSN: | 1661-6596 1422-0067 |