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

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.

ETHYLENE RESPONSE FACTOR 115 integrates jasmonate and cytokinin signaling machineries to repress adventitious rooting in Arabidopsis

“…The Agrobacterium ‐mediated floral dip method (Clough & Bent, 1998) was used to transform the construct into rap2‐6l‐1 or erf115 mutants. T1 seedlings were screened on Arabidopsis growth medium (Lakehal et al ., 2019b) containing 50 μg ml −1 hygromycin and surviving seedlings were genotyped for deletions in ERF114 using primers listed in Table S2 (see later). Several independent homozygous and heterozygous T1 lines were identified.…”

“…All the expression vectors were confirmed by colony PCR and sequencing, then transformed into GV3101 Agrobacterium tumefaciens cells, which were used to transform ninja‐1myc2‐332B double mutants using the floral dip method (Clough & Bent, 1998). Single‐copy, homozygous lines were selected by cultivating representatives of T2 and T3 generations on Arabidopsis medium (Lakehal et al ., 2019b) supplemented with 10 µg ml −1 DL‐phosphinothricin (Duchefa Biochemie, Haarlem, the Netherlands, https://www.duchefa‐biochemie.com/). At least two lines carrying each construct showing the same phenotype were further characterized.…”

Red Light Controls Adventitious Root Regeneration by Modulating Hormone Homeostasis in Picea abies Seedlings

“…Moreover, JA induces the expression of DIOXYGENASE FOR AUXIN OXIDATION 1 (DAO1) in a CORNATINE INSENSTIVE1(COI1)-dependent way. DAO1 is a key enzyme catalyzing the irreversible degradation of auxin, to ensure robust crosstalk between auxin and JA signaling pathways (Lakehal et al, 2019b). However, the extent to which these complex molecular networks are evolutionarily conserved among plant species is poorly understood, especially for trees.…”

Molecular Bases for the Regulation of Adventitious Root Generation in Plants

“…Another feedback circuit consist of DAO1, IAA, and COI1-dependent JA signaling. COI1-dependent JA signaling actives the expression of DAO1, which in turn regulates IAA homeostasis by irreversible degradation ( Lakehal et al, 2019b ). Copeland (2020) and Yin et al (2020) proposed a model of the involvement of SAUR15 in auxin signaling-mediated AR formation in Arabidopsis seedlings.…”