A DAO1-Mediated Circuit Controls Auxin and Jasmonate Crosstalk Robustness during Adventitious Root Initiation in Arabidopsis.

Abdellah Lakehal,Catherine Bellini,Asma Dob,Ondřej Novák

doi:10.3390/ijms20184428

Abstract

Adventitious rooting is a post-embryonic developmental program governed by a multitude of endogenous and environmental cues. Auxin, along with other phytohormones, integrates and translates these cues into precise molecular signatures to provide a coherent developmental output. Auxin signaling guides every step of adventitious root (AR) development from the early event of cell reprogramming and identity transitions until emergence. We have previously shown that auxin signaling controls the early events of AR initiation (ARI) by modulating the homeostasis of the negative regulator jasmonate (JA). Although considerable knowledge has been acquired about the role of auxin and JA in ARI, the genetic components acting downstream of JA signaling and the mechanistic basis controlling the interaction between these two hormones are not well understood. Here we provide evidence that COI1-dependent JA signaling controls the expression of DAO1 and its closely related paralog DAO2. In addition, we show that the dao1-1 loss of function mutant produces more ARs than the wild type, probably due to its deficiency in accumulating JA and its bioactive metabolite JA-Ile. Together, our data indicate that DAO1 controls a sensitive feedback circuit that stabilizes the auxin and JA crosstalk during ARI.

Highlights

Adventitious rooting is a post-embryonic developmental program enabling new roots to arise and branch out from the aboveground plant organs
We have previously shown that AUXIN RESPONSE FACTOR 6 (ARF6) and ARF8-mediated auxin signaling inhibit JA accumulation by enhancing its inactivation into amino acid conjugates in Arabidopsis hypocotyls during adventitious root initiation (ARI) [22]
ARI is a post-embryonic developmental program governed by a number of hormone signaling pathways [4] that interact and regulate each other at different levels to provide rapid molecular signatures in response to dynamic inductive cues

Summary

Introduction

Adventitious rooting is a post-embryonic developmental program enabling new roots to arise and branch out from the aboveground plant organs. The ability of plant species to reprogram their differentiated cells into new meristematic-like cells requires precise molecular signatures. These signatures can be generated by an intrinsic developmental cue or by a multitude of environmental ones [1,2,3]. The ability of plants to perceive and translate these inductive cues is an evolutionary fitness trait, providing them with the capacity to regenerate and clonally propagate as well as form extra roots whenever needed. How plants sense and integrate different inductive cues to trigger cell-identity transition programs leading to adventitious root initiation (ARI) is poorly understood. It is evident that, along with several signaling molecules, phytohormones play a prominent role in the integration of these cues to define suitable cell-fate decisions [4]

Methods

Results

Conclusion