Cytokinin signaling promotes root hair growth by directly regulating RSL4 expression
Cytokinin signaling promotes root hair growth by directly regulating RSL4 expression
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DOI：
10.1093/jxb/erad091
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发表时间：
2023-03-13
影响因子：
6.9
通讯作者：
Umeda, Masaaki
中科院分区：
文献类型：
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作者：
Takatsuka, Hirotomo;Sasaki, Anna;Umeda, Masaaki
根毛是由表皮产生的单细胞管状结构，在从土壤中吸收水分和养分方面起着重要作用。因此，根毛的形成和伸长不仅受发育程序的控制，还受环境因素的控制，使植物能够在波动的条件下生存。植物激素是将环境因素与发育计划联系起来的关键信号；事实上，已知根毛伸长是由生长素和乙烯控制的。另一种植物激素细胞分裂素也影响根毛生长，但细胞分裂素是否积极参与根毛生长，如果是，它如何调节控制根毛发育的信号通路仍然未知。在本研究中，我们发现细胞分裂素的双组分系统，包括b型响应调节因子ARABIDOPSIS response REGULATOR 1 （ARR1）和ARR12，促进根毛伸长过程。它们直接上调根毛缺陷6-LIKE 4 （RSL4）编码的基本螺旋-环-螺旋（bHLH）转录因子，而ARR1/12-RSL4途径不与生长素或乙烯信号通路串扰。这些结果表明，细胞分裂素信号是RSL4调控模块的另一个输入，使得在不断变化的环境中微调根毛生长成为可能。细胞分裂素通过b型应答调节因子ARR1和ARR12促进根毛生长，诱导rsl4编码基本的螺旋-环-螺旋转录因子，独立于乙烯或生长素信号传导。
Root hairs are single-celled tubular structures produced from the epidermis, which play an essential role in water and nutrient uptake from the soil. Therefore, root hair formation and elongation are controlled not only by developmental programs but also by environmental factors, enabling plants to survive under fluctuating conditions. Phytohormones are key signals that link environmental cues to developmental programs; indeed, root hair elongation is known to be controlled by auxin and ethylene. Another phytohormone, cytokinin, also affects root hair growth, while whether cytokinin is actively involved in root hair growth and, if so, how it regulates the signaling pathway governing root hair development have remained unknown. In this study, we show that the two-component system of cytokinin, which involves the B-type response regulators ARABIDOPSIS RESPONSE REGULATOR 1 (ARR1) and ARR12, promotes the elongation process of root hairs. They directly up-regulate ROOT HAIR DEFECTIVE 6-LIKE 4 (RSL4) encoding a basic helix-loop-helix (bHLH) transcription factor that plays a central role in root hair growth, whereas the ARR1/12-RSL4 pathway does not crosstalk with auxin or ethylene signaling. These results indicate that cytokinin signaling constitutes another input onto the regulatory module governed by RSL4, making it possible to fine-tune root hair growth in changing environments.Cytokinin promotes root hair growth through the B-type response regulators ARR1 and ARR12, which induce RSL4encoding the basic helix-loop-helix transcription factor independently of ethylene or auxin signaling.