Spatiotemporal control of axillary meristem formation by interacting transcriptional regulators.

Jin Wang,Wolfgang Werr,Cui Zhang,Yuling Jiao,John W Chandler,Stephan Wenkel

doi:10.1242/dev.158352

Abstract

ABSTRACTBranching is a common feature of plant development. In seed plants, axillary meristems (AMs) initiate in leaf axils to enable lateral shoot branching. AM initiation requires a high level of expression of the meristem marker SHOOT MERISTEMLESS (STM) in the leaf axil. Here, we show that modules of interacting transcriptional regulators control STM expression and AM initiation. Two redundant AP2-type transcription factors, DORNRÖSCHEN (DRN) and DORNRÖSCHEN-LIKE (DRNL), control AM initiation by regulating STM expression. DRN and DRNL directly upregulate STM expression in leaf axil meristematic cells, as does another transcription factor, REVOLUTA (REV). The activation of STM expression by DRN/DRNL depends on REV, and vice versa. DRN/DRNL and REV have overlapping expression patterns and protein interactions in the leaf axil, which are required for the upregulation of STM expression. Furthermore, LITTLE ZIPPER3, another REV-interacting protein, is expressed in the leaf axil and interferes with the DRN/DRNL-REV interaction to negatively modulate STM expression. Our results support a model in which interacting transcriptional regulators fine-tune the expression of STM to precisely regulate AM initiation. Thus, shoot branching recruits the same conserved protein complexes used in embryogenesis and leaf polarity patterning.

Highlights

In contrast to animals, plants are sessile organisms with an enormous developmental plasticity to adapt to the changing environment
DORNRÖ SCHEN (DRN) and DORNRÖ SCHENLIKE (DRNL) redundantly control axillary bud formation We have recently shown via a genome-wide study that DRN is required for axillary meristems (AMs) initiation (Tian et al, 2014)
This current study aimed to understand in more detail how DRN regulates the formation of AMs in rosette leaf axils in the vegetative shoots

Summary

Introduction

Plants are sessile organisms with an enormous developmental plasticity to adapt to the changing environment. To this end, plants have innovated a branching growth habit (Coudert et al, 2015). Shoot branches arise from axillary meristems (AMs, termed lateral meristems) in, or near, the leaf axils (Schmitz and Theres, 2005; Wang and Jiao, 2018). Axillary bud development comprises two stages: initiation in The final pattern of branches to a large extent determines the architecture of the shoot system

Methods

Results

Conclusion