BRANCHED1 Orchestrates an ABA Gene Regulatory Network to Promote axillary bud dormancy in Arabidopsis

The control of branch outgrowth is critical for plant fitness, stress resilience and crop yield. The Arabidopsis thaliana transcription factor BRANCHED1 (BRC1) plays a pivotal role in this process: it integrates signals that control shoot branching to inhibit axillary bud growth. Despite the remarkable activity of BRC1 as a potent growth inhibitor, the mechanisms by which it promotes and maintains bud dormancy are still largely unknown. Here we combine ChIP-seq, transcriptomic and systems biology approaches to characterize the BRC1-regulated gene network. We identify a group of BRC1 direct target genes encoding transcription factors (BTFs) that orchestrate, together with BRC1, an intricate transcriptional network enriched in ABA signalling components. The BRC1 network is enriched in feed-forward loops and feed-back loops, robust against noise and mutation, reversible in response to stimuli, and stable once established. This knowledge which will prove fundamental to adapt plant architecture and crop production to an ever-changing climate. Overall design: Induction experiment of BRC1 using an estradiol induction system. RNA-seq was performed on tissue from the inducible line (GFP-BRC1ind) and the brc1-2 k.o as control. A ChIP-seq was performed on the inducible line with Input as control. Ten day old seedlings were treated with 5ml of 10uM estradiol on plate. Tissue was harvested after 5 hours.