HB21 induction in Arabidopsis inflorescence apexes
HB21 is a homeodomain leucine zipper transcription factor involved in the establishment of bud axillary dormancy. In this work we have characterized the role of HB21 in the control of the inflorescence arrest at the end of flowering. HB21, together with HB40 and HB53, are upregulated in the inflorescence apex at the end of the flowering phase promoting the floral bud arrest associated with the process. We also show that ABA accumulation occurs in the inflorescence apex at the end of flowering in physiological conditions, and that this accumulation depends on HB genes. Our work has allowed us to propose a physiological role of ABA in the control of floral bud arrest at the end of flowering Overall design: To obtain more clues on the mechanism and the regulatory networks acting downstream the HB genes in the control of inflorescence arrest we analyzed the transcriptomic response to changes in HB activity in this context. An HB21 dexamethasone inducible line (HB21ind) was used to overcome the redundancy with HB53 and HB40. We treated inflorescence apexes of 2 wab HB21ind lines (active meristems with low endogenous expression of HB21) with Dex or mock. Then, 6 hours post-treatment, we collected inflorescence apexes. 3 independent biological replicates for each treatment were used for RNA sequencing. Transcripts with a log2 fold change (FC) >1 and <-1, and a p-adjusted value < 0.05 were considered as differentially expressed genes (DEG) and selected for further analysis. We obtained 1143 DEGs, 471 activated and 672 repressed by HB21 induction