标题：WOX5-IAA17 feedback circuit-mediated cellular auxin response is crucial for the patterning of root stem cell niches in Arabidopsis.
作者：Tian HuiYu;Wabnik, K.;Niu TianTian;Li HanBing;Yu QianQian;Pollmann, S.;Vanneste, S.;Govaerts, W.;Rolcik, J.;Geisler, M.;Friml, J
作者机构：[Tian, H] Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, Shandong University, Shanda Nanlu 27, Jinan 250100 更多
通讯作者地址：[Ding, ZJ]Shandong Univ, Sch Life Sci, Minist Educ, Key Lab Plant Cell Engn & Germplasm Innovat, Shanda Nanlu 27, Jinan 250100, Peoples R China.
关键词：WOX5;auxin maximum;IAA17/AXR3;root patterning;computer simulation
摘要：In plants, the patterning of stem cell-enriched meristems requires a graded auxin response maximum that emerges from the concerted action of polar auxin transport, auxin biosynthesis, auxin metabolism, and cellular auxin response machinery. However, mechanisms underlying this auxin response maximum-mediated root stem cell maintenance are not fully understood. Here, we present unexpected evidence that WUSCHEL-RELATED HOMEOBOX 5 (WOX5) transcription factor modulates expression of auxin biosynthetic genes in the quiescent center (QC) of the root and thus provides a robust mechanism for the maintenance of auxin response maximum in the root tip. This WOX5 action is balanced through the activity of indole-3-acetic acid 17 (IAA17) auxin response repressor. Our combined genetic, cell biology, and computational modeling studies revealed a previously uncharacterized feedback loop linking WOX5-mediated auxin production to IAA17-dependent repression of auxin responses. This WOX5-IAA17 feedback circuit further assures the maintenance of auxin response maximum in the root tip and thereby contributes to the maintenance of distal stem cell (DSC) populations. Our experimental studies and in silico computer simulations both demonstrate that the WOX5-IAA17 feedback circuit is essential for the maintenance of auxin gradient in the root tip and the auxin-mediated root DSC differentiation.