PHB3 Maintains Root Stem Cell Niche Identity through ROS-Responsive AP2/ERF Transcription Factors in Arabidopsis

Xiangpei Kong,Huiyu Tian,Qianqian Yu,Feng Zhang,Rong Wang,Shan Gao,Wenhong Xu,Jiajia Liu,Eilon Shani,Chunxiang Fu,Gongke Zhou,Liangran Zhang,Xiansheng Zhang,Zhaojun Ding

doi:10.1016/j.celrep.2017.12.105

Abstract

The root stem cell niche, which is composed of four mitotically inactive quiescent center (QC) cells and the surrounding actively divided stem cells in Arabidopsis, is critical for growth and root development. Here, we demonstrate that the Arabidopsis prohibitin protein PHB3 is required for the maintenance of root stem cell niche identity by both inhibiting proliferative processes in the QC and stimulating cell division in the proximal meristem (PM). PHB3 coordinates cell division and differentiation in the root apical meristem by restricting the spatial expression of ethylene response factor (ERF) transcription factors 115, 114, and 109. ERF115, ERF114, and ERF109 mediate ROS signaling, in a PLT-independent manner, to control root stem cell niche maintenance and root growth through phytosulfokine (PSK) peptide hormones in Arabidopsis.

Highlights

The development of the root relies on the continuous provision of new cells by the stem cell niche (SCN), which is located within the root apical meristem (RAM) (Aichinger et al, 2012; Yang et al, 2015)
All these results indicate that PHB3 is required for maintaining the cell division activity of the root meristem
The root SCN-defining transcription factors, such as PLT1, PLT2, and SCR, were all strongly downregulated in phb3 (Figure 2), which is consistent with the root-defective phenotypes

Summary

Introduction

The development of the root relies on the continuous provision of new cells by the stem cell niche (SCN), which is located within the root apical meristem (RAM) (Aichinger et al, 2012; Yang et al, 2015). In RAM, coordinated balance between cell division and differentiation determines meristem size. Maintenance of the root SCN in A. thaliana requires the activity of the homeobox transcription factor WOX5, which is transcribed in the QC and maintains the identity of both the QC and the distal stem cells (DSCs) (Sarkar et al, 2007; Kong et al, 2015). WOX5 inhibits cell division in the QC by suppressing CYCD3;3, and it moves from the QC into the DSCs (Forzani et al, 2014) where it represses the differentiation factor CDF4 to inhibit root DSC differentiation via recruiting TPL/TPR co-repressors and the histone deacetylase HDA19 (Pi et al, 2015). Auxin signaling and REPRESSOR OF WUSCHEL1 (ROW1) regulate DSC differentiation and proximal meristem (PM) differentiation by acting on WOX5, respectively (Ding and Friml, 2010; Zhang et al, 2015)

Results

Discussion

Conclusion