Plant hormone and peptide signaling converge in the genetic network regulating cambium activation in Arabidopsis roots [axr3-1_RNA-Seq]

The periclinal cell divisions of both meristems, providing thickness and protection to plant organs, are activated with a delay after the primary development. Cytokinins and a set of downstream transcription factors are key players in promoting transition from primary to secondary development, however it is unknown whether other factors play a role in this transition.

Here, using time-course transcriptome analysis of cytokinin-treated, cytokinin deficient isopentenyltransferase1,3,5,7 (ipt1,3,5,7) mutant we show that during cambium activation cytokinins positively regulate auxin and TRACHEARY ELEMENT DIFFERENTIATION INHIBITORY FACTOR (TDIF) peptide signaling in Arabidopsis (Arabidopsis thaliana) root. Correspondingly, mutants defective in TDIF peptide signaling displayed reduced cytokinin-induced secondary growth and auxin signaling was found to be required for proper cytokinin response.