Exogenous Auxin Induces Transverse Microtubule Arrays Through TRANSPORT INHIBITOR RESPONSE1/AUXIN SIGNALING F-BOX Receptors
Exogenous Auxin Induces Transverse Microtubule Arrays Through TRANSPORT INHIBITOR RESPONSE1/AUXIN SIGNALING F-BOX Receptors
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DOI：
10.1104/pp.19.00928
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发表时间：
2020-02-01
期刊：
影响因子：
7.4
通讯作者：
Shaw, Sidney L.
中科院分区：
文献类型：
--
作者：
True, Jillian H.;Shaw, Sidney L.
生长素在控制植物细胞生长和形态发生中起着重要作用。应用生长素促进光生幼苗的轴向生长和下胚轴皮层微管细胞骨架的横向构型。微管在5分钟内对外源生长素产生反应，尽管阵列的重新图案化直到施用后30分钟才开始，并且在2小时内完成。为了研究生长素诱导的微管阵列图案化的要求，我们使用了拟南芥（拟南芥）双生长素f盒（afb）受体突变体，afb 4 -8 afb 5 -5，响应于传统的生长素（吲哚-3-乙酸），但具有强烈减弱的响应生长素类似物，毒莠定。我们发现，5 μ m氨氯吡啶酸诱导立即改变微管密度和后来的横向微管图案在野生型植物，但不会导致微管阵列重组afb 4 -8 afb 5 -5突变体。此外，生长素辅助受体AUXIN RESPONSIVE 2（AXR 2）的显性突变体（axr 2 -1）被强烈抑制生长素诱导的微管阵列重组，提供了额外的证据，生长素功能通过转录途径的横向图案。我们观察到，油菜素类固醇应用模仿生长素的反应，显示早期和晚期微管阵列的影响，并诱导axr 2 -1突变体的横向图案。将生长素应用于油菜素类固醇合成突变体diminuto 1，诱导横向阵列图案，但没有产生显着的轴向生长。因此，外源生长素通过转运抑制剂1/生长素F-BOX（TIR 1/AFB）转录途径诱导横向微管图案化，并且可以独立于油菜素类固醇发挥作用。
Auxin plays a central role in controlling plant cell growth and morphogenesis. Application of auxin to light-grown seedlings elicits both axial growth and transverse patterning of the cortical microtubule cytoskeleton in hypocotyl cells. Microtubules respond to exogenous auxin within 5 min, although repatterning of the array does not initiate until 30 min after application and is complete by 2 h. To examine the requirements for auxin-induced microtubule array patterning, we used an Arabidopsis (Arabidopsis thaliana) double auxin f-box (afb) receptor mutant, afb4-8 afb5-5, that responds to conventional auxin (indole-3-acetic acid) but has a strongly diminished response to the auxin analog, picloram. We show that 5 mu m picloram induces immediate changes to microtubule density and later transverse microtubule patterning in wild-type plants, but does not cause microtubule array reorganization in the afb4-8 afb5-5 mutant. Additionally, a dominant mutant (axr2-1) for the auxin coreceptor AUXIN RESPONSIVE2 (AXR2) was strongly suppressed for auxin-induced microtubule array reorganization, providing additional evidence that auxin functions through a transcriptional pathway for transverse patterning. We observed that brassinosteroid application mimicked the auxin response, showing both early and late microtubule array effects, and induced transverse patterning in the axr2-1 mutant. Application of auxin to the brassinosteroid synthesis mutant, diminuto1, induced transverse array patterning but did not produce significant axial growth. Thus, exogenous auxin induces transverse microtubule patterning through the TRANSPORT INHIBITOR 1/AUXIN F-BOX (TIR1/AFB) transcriptional pathway and can act independently of brassinosteroids.