IAA Accumulation Promotes the Root Growth of Tea Plants under Aluminum
A moderate supply of aluminum (Al) can promote the root growth of plant species, such as tea, that have adapted to acid soils. The formation and development of roots are regulated by phytohormones. However, the role that phytohormones play in facilitating the beneficial effects of Al on root growth...
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MDPI AG
2022-05-01
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| Series: | Agronomy |
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| Online Access: | https://www.mdpi.com/2073-4395/12/5/1110 |
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| author | Yaoyao Gao Min Wang Yifan Shi Liu Yang Jianhui Hu Kai Fan Yuanzhi Shi |
| author_facet | Yaoyao Gao Min Wang Yifan Shi Liu Yang Jianhui Hu Kai Fan Yuanzhi Shi |
| author_sort | Yaoyao Gao |
| collection | DOAJ |
| description | A moderate supply of aluminum (Al) can promote the root growth of plant species, such as tea, that have adapted to acid soils. The formation and development of roots are regulated by phytohormones. However, the role that phytohormones play in facilitating the beneficial effects of Al on root growth is unclear. In the present study, tea plants cultured hydroponically with either 0 or 0.4 mmol/L Al were characterized and compared in terms of root growth, hormone concentrations, and the expression of related genes. The hormone content in tea roots was measured by UPLC–MS, and the expression levels of genes involved in phytohormone biosynthesis, transport, and response were analyzed by qRT-PCR. Our results showed that the indole acetic acid (IAA) concentrations in the root base were significantly higher in plants supplied with Al compared to control plants without Al during the experimental period from 6 h to 7 d. By using inhibitors of IAA synthesis and transport, we found that Al induces short-term IAA synthesis in the root tip and enhances IAA transport in other parts of the root over the longer term, thus promoting root growth in tea plants by limiting IAA accumulation. The expression levels of genes <i>YUC8</i> and <i>AMI1</i>, involved in IAA accumulation, were consistently upregulated in the root tip, whereas expression of <i>PIN1/2/8</i>, involved in IAA transport, was induced in the root base under Al supply at 6 h. In addition, the expression of <i>PIN2</i> and <i>PIN5</i> was highly induced in root stem by Al after 7 d and probably contributed to alleviating IAA accumulation in the root tip and thereby promoted root growth in tea plants. Meanwhile, the XET and expansin activities were increased under Al supply at 6 h. Thus, we conclude that the mechanism of Al-induced root growth is mediated by auxin accumulation and transport in cooperation with cell wall loosening in tea plants. |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-10T03:30:06Z |
| publishDate | 2022-05-01 |
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| series | Agronomy |
| spelling | doaj.art-3d213223713248598a4296ca0ac25a652023-11-23T09:42:57ZengMDPI AGAgronomy2073-43952022-05-01125111010.3390/agronomy12051110IAA Accumulation Promotes the Root Growth of Tea Plants under AluminumYaoyao Gao0Min Wang1Yifan Shi2Liu Yang3Jianhui Hu4Kai Fan5Yuanzhi Shi6Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, ChinaTea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, ChinaJianxing Hornors College, Zhejiang University of Technology, Hangzhou 310023, ChinaTea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, ChinaTea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, ChinaTea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, ChinaTea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, ChinaA moderate supply of aluminum (Al) can promote the root growth of plant species, such as tea, that have adapted to acid soils. The formation and development of roots are regulated by phytohormones. However, the role that phytohormones play in facilitating the beneficial effects of Al on root growth is unclear. In the present study, tea plants cultured hydroponically with either 0 or 0.4 mmol/L Al were characterized and compared in terms of root growth, hormone concentrations, and the expression of related genes. The hormone content in tea roots was measured by UPLC–MS, and the expression levels of genes involved in phytohormone biosynthesis, transport, and response were analyzed by qRT-PCR. Our results showed that the indole acetic acid (IAA) concentrations in the root base were significantly higher in plants supplied with Al compared to control plants without Al during the experimental period from 6 h to 7 d. By using inhibitors of IAA synthesis and transport, we found that Al induces short-term IAA synthesis in the root tip and enhances IAA transport in other parts of the root over the longer term, thus promoting root growth in tea plants by limiting IAA accumulation. The expression levels of genes <i>YUC8</i> and <i>AMI1</i>, involved in IAA accumulation, were consistently upregulated in the root tip, whereas expression of <i>PIN1/2/8</i>, involved in IAA transport, was induced in the root base under Al supply at 6 h. In addition, the expression of <i>PIN2</i> and <i>PIN5</i> was highly induced in root stem by Al after 7 d and probably contributed to alleviating IAA accumulation in the root tip and thereby promoted root growth in tea plants. Meanwhile, the XET and expansin activities were increased under Al supply at 6 h. Thus, we conclude that the mechanism of Al-induced root growth is mediated by auxin accumulation and transport in cooperation with cell wall loosening in tea plants.https://www.mdpi.com/2073-4395/12/5/1110<i>Camellia sinensis</i>Alrootphytohormoneindole acetic acid (IAA) |
| spellingShingle | Yaoyao Gao Min Wang Yifan Shi Liu Yang Jianhui Hu Kai Fan Yuanzhi Shi IAA Accumulation Promotes the Root Growth of Tea Plants under Aluminum Agronomy <i>Camellia sinensis</i> Al root phytohormone indole acetic acid (IAA) |
| title | IAA Accumulation Promotes the Root Growth of Tea Plants under Aluminum |
| title_full | IAA Accumulation Promotes the Root Growth of Tea Plants under Aluminum |
| title_fullStr | IAA Accumulation Promotes the Root Growth of Tea Plants under Aluminum |
| title_full_unstemmed | IAA Accumulation Promotes the Root Growth of Tea Plants under Aluminum |
| title_short | IAA Accumulation Promotes the Root Growth of Tea Plants under Aluminum |
| title_sort | iaa accumulation promotes the root growth of tea plants under aluminum |
| topic | <i>Camellia sinensis</i> Al root phytohormone indole acetic acid (IAA) |
| url | https://www.mdpi.com/2073-4395/12/5/1110 |
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