Dual Regulatory Roles of SlGAMYB1 in Tomato Development: GA-Dependent and GA-Independent Mechanisms
The R2R3-MYB transcription factor GAMYB plays crucial roles in plant growth and development, but the biological functions of <i>SlGAMYB1</i> in tomato remain poorly understood. Here, we investigated the roles of <i>SlGAMYB1</i> by overexpressing a miR159-resistant version (&l...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-05-01
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| Series: | Plants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2223-7747/14/11/1613 |
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| Summary: | The R2R3-MYB transcription factor GAMYB plays crucial roles in plant growth and development, but the biological functions of <i>SlGAMYB1</i> in tomato remain poorly understood. Here, we investigated the roles of <i>SlGAMYB1</i> by overexpressing a miR159-resistant version (<i>35S:SlGAMYB1<sup>m</sup></i>) in tomato. Transgenic plants exhibited a dwarf phenotype with reduced internode elongation, which was associated with decreased bioactive gibberellin (GA) levels due to transcriptional repression of <i>SlGA3ox1</i> and activation of <i>SlGA2ox1/2/4/5</i>. Additionally, <i>35S:SlGAMYB1<sup>m</sup></i> altered leaf morphology by inhibiting cell proliferation through downregulation of cell cycle genes, resulting in larger but fewer epidermal cells. Intriguingly, <i>35S:SlGAMYB1<sup>m</sup></i> plants displayed increased floral organ number, a process likely mediated by the upregulation of <i>SlWUS</i> rather than GA signaling. These findings demonstrate that <i>SlGAMYB1</i> regulates diverse aspects of tomato development through both GA-dependent and independent pathways, providing new insights into the functional diversification of <i>GAMYB</i> genes and potential strategies for genetic improvement of tomato architecture and yield. |
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| ISSN: | 2223-7747 |