KAI2 regulates root and root hair development by modulating auxin distribution
KAI2 regulates root and root hair development by modulating auxin distribution
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DOI：
10.1101/539734
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发表时间：
2019-02
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通讯作者：
J. Villaécija-Aguilar;Maxime Hamon-Josse;Samy Carbonnel;A. Kretschmar;K. Ljung;Tom Bennett;C. Gutjahr
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作者：
J. Villaécija-Aguilar;Maxime Hamon-Josse;Samy Carbonnel;A. Kretschmar;K. Ljung;Tom Bennett;C. Gutjahr
独脚金内酯（Strigolactones，SL）是一类内源性信号分子，在植物生长发育中起重要作用。SL感知与karrikins的感知密切相关，karrikins是推测模拟内源性信号分子（KLs）的烟雾衍生化合物。SL已经被认为调节根的发育。然而，这两种分子的感知需要F-盒蛋白MAX2，并且MAX2突变体的使用阻碍了确定SL在根中的确切作用。在这里，我们剖析了SL和KL信号在拟南芥根发育中的作用，使用α/β水解酶受体D14和KAI 2缺陷的突变体，它们分别特异性地感知SL和KL。这两种途径一起调节侧根密度（LRD），但与以前的报道相反，KL信号单独控制根毛密度，根毛长度和另外的根偏斜，平直度和直径。SMXL蛋白家族的成员是SL（SMXL 6、7、8）和KL（SMAX 1、SMXL 2）信号传导的下游靶标。我们确定了不同的和重叠的作用，这些蛋白质在根发育的调节。SMAX 1/SMXL 2和SMXL 6/SMXL 7/SMXL 8均调节LRD，证实SL和KL信号传导共同作用以调节该性状，而KL信号传导特异性SMAX 1和SMXL 2调节所有其他研究的根性状。最后，我们表明，KL信号调节根毛的发展，通过调节生长素的根内分布。
Strigolactones (SLs) are endogenous signalling molecules that play important roles in controlling plant development. SL perception is closely related to that of karrikins, smoke-derived compounds presumed to mimic endogenous signalling molecules (KLs). SLs have been suggested to regulate root development. However, perception of both molecules requires the F-box protein MAX2 and the use of max2 mutants has hampered defining the exact role of SLs in roots. Here we dissect the role of SL and KL signalling in Arabidopsis root development using mutants defective in the α/β hydrolase receptors D14 and KAI2, which specifically perceive SLs and KLs, respectively. Both pathways together regulate lateral root density (LRD), but contrary to previous reports, KL signalling alone controls root hair density, root hair length and additionally root skewing, straightness and diameter. Members of the SMXL protein family are downstream targets of SL (SMXL6, 7, 8) and KL (SMAX1, SMXL2) signalling. We identified distinct and overlapping roles of these proteins in the regulation of root development. Both SMAX1/SMXL2 and SMXL6/SMXL7/SMXL8 regulate LRD, confirming that SL and KL signalling act together to regulate this trait, while the KL-signalling specific SMAX1 and SMXL2 regulate all other investigated root traits. Finally, we show that KL signalling regulates root hair development by modulating auxin distribution within the root.