Auxin-Induced <i>SaARF4</i> Downregulates <i>SaACO4</i> to Inhibit Lateral Root Formation in <i>Sedum alfredii</i> Hance
Lateral root (LR) formation promotes plant resistance, whereas high-level ethylene induced by abiotic stress will inhibit LR emergence. Considering that local auxin accumulation is a precondition for LR generation, auxin-induced genes inhibiting ethylene synthesis may thus be important for LR develo...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-01-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/22/3/1297 |
| Summary: | Lateral root (LR) formation promotes plant resistance, whereas high-level ethylene induced by abiotic stress will inhibit LR emergence. Considering that local auxin accumulation is a precondition for LR generation, auxin-induced genes inhibiting ethylene synthesis may thus be important for LR development. Here, we found that auxin response factor 4 (<i>SaARF4</i>) in <i>Sedum alfredii</i> Hance could be induced by auxin. The overexpression of <i>SaARF4</i> decreased the LR number and reduced the vessel diameters. Meanwhile, the auxin distribution mode was altered in the root tips and <i>PIN</i> expression was also decreased in the overexpressed lines compared with the wild-type (WT) plants. The overexpression of <i>SaARF4</i> could reduce ethylene synthesis, and thus, the repression of ethylene production decreased the LR number of WT and reduced <i>PIN</i> expression in the roots. Furthermore, the quantitative real-time PCR, chromatin immunoprecipitation sequencing, yeast one-hybrid, and dual-luciferase assay results showed that <i>SaARF4</i> could bind the promoter of 1-aminocyclopropane-1-carboxylate oxidase 4 (<i>SaACO4</i>), associated with ethylene biosynthesis, and could downregulate its expression. Therefore, we concluded that <i>SaARF4</i> induced by auxin can inhibit ethylene biosynthesis by repressing <i>SaACO4</i> expression, and this process may affect auxin transport to delay LR development. |
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| ISSN: | 1661-6596 1422-0067 |