AUX1 regulates root gravitropism in Arabidopsis by facilitating auxin uptake within root apical tissues
AUX1 regulates root gravitropism in Arabidopsis by facilitating auxin uptake within root apical tissues
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DOI：
10.1093/emboj/18.8.2066
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发表时间：
1999-04-15
期刊：
影响因子：
11.4
通讯作者：
Bennett, MJ
中科院分区：
文献类型：
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作者：
Marchant, A;Kargul, J;Bennett, MJ
植物利用一个由不同的流入和流出载体组成的专门的运输系统在植物激素生长素的合成和作用位点之间调动。透膜样AUX1蛋白的突变显著降低了拟南芥根系中载体介导的生长素摄取速率，赋予其向地性表型。我们能够绕过生长素摄取中的缺陷，通过在膜透性合成蛋白l-萘乙酸的存在下生长突变苗，恢复AUX1的向地性根系表型。我们利用表达AUX1启动子：：uidA （GUS）基因的转基因系，证明了AUX1的表达与之前描述的生长素外排载体AtPIN2的表达重叠。最后，我们证明了AUX1通过与生长素外溢载体协调生长素在拟南芥根尖的局部再分配来调节向地性曲率。我们的研究结果为高等植物中生长素内流载体的发育作用提供了第一个例子，并为向地性信号传导的分子基础提供了新的见解。
Plants employ a specialized transport system composed of separate influx and efflux carriers to mobilize the plant hormone auxin between its site(s) of synthesis and action. Mutations within the permease-like AUX1 protein significantly reduce the rate of carrier-mediated auxin uptake within Arabidopsis roots, conferring an agravitropic phenotype, We are able to bypass the defect within auxin uptake and restore the gravitropic root phenotype of aux1 by growing mutant seedlings in the presence of the membrane-permeable synthetic awin, l-naphthaleneacetic acid. We illustrate that AUX1 expression overlaps that previously described for the auxin efflux carrier, AtPIN2, using transgenic lines expressing an AUX1 promoter::uidA (GUS) gene. Finally, we demonstrate that AUX1 regulates gravitropic curvature by acting in unison with the auxin efflux carrier to co-ordinate the localized redistribution of auxin within the Arabidopsis root apex. Our results provide the first example of a developmental role for the auxin influx carrier within higher plants and supply new insight into the molecular basis of gravitropic signalling.