LcMYB2, a R2R3-MYB Transcription Factor, Regulates Anthocyanin and Proanthocyanidin Biosynthesis in Litchi chinensis Through Interaction with LcbHLH3
2025
Biao Lai | Li Jiang | Qi Zhu | Chongying Xie | Xiangyu Gong | Guolu He | Shuyi Zhang | Gangjun Luo | Huicong Wang | Lina Du | Guibing Hu
Litchi (Litchi chinensis Sonn.) is a popular subtropical fruit with a red pericarp that is primarily determined by the accumulation of anthocyanins. The peel color and fruit quality are also influenced by proanthocyanins (PAs), which play roles in fruit development and postharvest quality. In this study, we identified LcMYB2 as a key regulator of both anthocyanin and PA biosynthesis in litchi. Phylogenetic analysis revealed that LcMYB2 belongs to the VvMYB5 subclade. Expression analysis showed that LcMYB2 is highly expressed in the early stages of fruit development. Its expression pattern was consistent with that of LcLAR and LcANR, two key genes in the PA biosynthetic pathway. Subcellular localization and protein&ndash:protein interaction assays confirmed that LcMYB2 localizes to the nucleus and interacts with LcbHLH3. Dual-luciferase reporter assays demonstrated that the LcMYB2-LcbHLH3 complex activates the promoters of LcLAR and LcANR, supporting its role in regulating PA biosynthesis. Furthermore, overexpression of LcMYB2 in tobacco resulted in the synthesis of anthocyanins and PAs in the flower, indicating that LcMYB2 can regulate anthocyanin and PA biosynthesis. Additionally, transgenic tobacco plants with LcMYB2 overexpression exhibited delayed anther dehiscence, suggesting a broader role in plant development. These findings highlight the multifunctional nature of LcMYB2 in regulating both anthocyanin and PA biosynthesis, as well as its involvement in reproductive development.
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