scholarly journals Multiple AUX/IAA–ARF modules regulate lateral root formation: the role of Arabidopsis SHY2/IAA3-mediated auxin signalling

2012 ◽  
Vol 367 (1595) ◽  
pp. 1461-1468 ◽  
Author(s):  
Tatsuaki Goh ◽  
Hiroyuki Kasahara ◽  
Tetsuro Mimura ◽  
Yuji Kamiya ◽  
Hidehiro Fukaki
Keyword(s):  
Lateral Root ◽  
Target Gene ◽  
Root Formation ◽  
Auxin Response ◽  
Cell Specification ◽  
Asymmetric Cell Divisions ◽  
Auxin Signalling ◽  
Lateral Organ ◽  
Indole 3 Acetic Acid

In Arabidopsis thaliana , lateral root (LR) formation is regulated by multiple auxin/indole-3-acetic acid (Aux/IAA)–AUXIN RESPONSE FACTOR (ARF) modules: (i) the IAA28–ARFs module regulates LR founder cell specification; (ii) the SOLITARY-ROOT (SLR)/IAA14–ARF7–ARF19 module regulates nuclear migration and asymmetric cell divisions of the LR founder cells for LR initiation; and (iii) the BODENLOS/IAA12–MONOPTEROS/ARF5 module also regulates LR initiation and organogenesis. The number of Aux/IAA–ARF modules involved in LR formation remains unknown. In this study, we isolated the shy2-101 mutant, a gain-of-function allele of short hypocotyl2/suppressor of hy2 ( shy2 ) /iaa3 in the Columbia accession. We demonstrated that the shy2-101 mutation not only strongly inhibits LR primordium development and emergence but also significantly increases the number of LR initiation sites with the activation of LATERAL ORGAN BOUNDARIES-DOMAIN16/ASYMMETRIC LEAVES2-LIKE18 , a target gene of the SLR/IAA14–ARF7–ARF19 module. Genetic analysis revealed that enhanced LR initiation in shy2-101 depended on the SLR/IAA14–ARF7–ARF19 module. We also showed that the shy2 roots contain higher levels of endogenous IAA. These observations indicate that the SHY2/IAA3–ARF-signalling module regulates not only LR primordium development and emergence after SLR/IAA14–ARF7–ARF19 module-dependent LR initiation but also inhibits LR initiation by affecting auxin homeostasis, suggesting that multiple Aux/IAA–ARF modules cooperatively regulate the developmental steps during LR formation.

scholarly journals Nitrate Modulates Lateral Root Formation by Regulating the Auxin Response and Transport in Rice

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 850
Author(s):  
Bobo Wang ◽  
Xiuli Zhu ◽  
Xiaoli Guo ◽  
Xuejiao Qi ◽  
Fan Feng ◽  
...  
Keyword(s):  
Lateral Root ◽  
Root Formation ◽  
Signalling Pathways ◽  
Lateral Root Formation ◽  
Auxin Response ◽  
Short Term ◽  
Exogenous Auxin ◽  
Mutant Lines ◽  
Auxin Efflux Carrier

Nitrate (NO3-) plays a pivotal role in stimulating lateral root (LR) formation and growth in plants. However, the role of NO3- in modulating rice LR formation and the signalling pathways involved in this process remain unclear. Phenotypic and genetic analyses of rice were used to explore the role of strigolactones (SLs) and auxin in NO3--modulated LR formation in rice. Compared with ammonium (NH4+), NO3- stimulated LR initiation due to higher short-term root IAA levels. However, this stimulation vanished after 7 d, and the LR density was reduced, in parallel with the auxin levels. Application of the exogenous auxin α-naphthylacetic acid to NH4+-treated rice plants promoted LR initiation to levels similar to those under NO3- at 7 d; conversely, the application of the SL analogue GR24 to NH4+-treated rice inhibited LR initiation to levels similar to those under NO3- supply by reducing the root auxin levels at 14 d. D10 and D14 mutations caused loss of sensitivity of the LR formation response to NO3-. The application of NO3- and GR24 downregulated the transcription of PIN-FORMED 2(PIN2), an auxin efflux carrier in roots. LR number and density in pin2 mutant lines were insensitive to NO3- treatment. These results indicate that NO3- modulates LR formation by affecting the auxin response and transport in rice, with the involvement of SLs.

scholarly journals To branch or not to branch: the role of pre-patterning in lateral root formation

Development ◽  
2013 ◽  
Vol 140 (21) ◽  
pp. 4301-4310 ◽  
Author(s):  
J. M. Van Norman ◽  
W. Xuan ◽  
T. Beeckman ◽  
P. N. Benfey
Keyword(s):  
Lateral Root ◽  
Root Formation ◽  
Lateral Root Formation

scholarly journals AUX1 Promotes Lateral Root Formation by Facilitating Indole-3-Acetic Acid Distribution between Sink and Source Tissues in the Arabidopsis Seedling

2002 ◽  
Vol 14 (3) ◽  
pp. 589-597 ◽  
Author(s):  
Alan Marchant ◽  
Rishikesh Bhalerao ◽  
Ilda Casimiro ◽  
Jan Eklöf ◽  
Pedro J. Casero ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Lateral Root ◽  
Root Formation ◽  
Lateral Root Formation ◽  
Arabidopsis Seedling ◽  
Indole 3 Acetic Acid

scholarly journals Molecular framework for TIR1/AFB-Aux/IAA-dependent auxin sensing controlling adventitious rooting in Arabidopsis

2019 ◽  
Author(s):  
Abdellah Lakehal ◽  
Salma Chaabouni ◽  
Emilie Cavel ◽  
Rozenn Le Hir ◽  
Alok Ranjan ◽  
...  
Keyword(s):  
Indole Acetic Acid ◽  
Root Formation ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Loss Of Function ◽  
Auxin Response ◽  
Genetic Studies ◽  
Auxin Signalling ◽  
Positive Regulators ◽  
Molecular Framework

ABSTRACTIn Arabidopsis thaliana, canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR (ARF) family interacting with 29 auxin/indole acetic acid repressors (Aux/IAA), themselves forming coreceptor complexes with one of six TRANSPORT INHIBITOR1/AUXIN-SIGNALLING F-BOX (TIR1/AFB) PROTEINS. Different combinations of co-receptors drive specific sensing outputs, allowing auxin to control a myriad of processes. Considerable efforts have been made to discern the specificity of auxin action. However, owing to a lack of obvious phenotype in single loss-of-function mutants in Aux/IAA genes, most genetic studies have relied on gain-of-function mutants, which are highly pleiotropic. Using loss-of-function mutants, we show that three Aux/IAA proteins interact with ARF6 and/or ARF8, which we have previously shown to be positive regulators of AR formation upstream of jasmonate, and likely repress their activity. We also demonstrate that TIR1 and AFB2 are positive regulators of adventitious root formation and suggest a dual role for TIR1 in the control of JA biosynthesis and conjugation, as revealed by upregulation of several JA biosynthesis genes in the tir1-1 mutant. We propose that in the presence of auxin, TIR1 and AFB2 form specific sensing complexes with IAA6, IAA9 and/or IAA17 that modulate JA homeostasis to control AR initiation.

scholarly journals OsTCP19 influences developmental and abiotic stress signaling by modulatingABI4-mediated pathways

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Pradipto Mukhopadhyay ◽  
Akhilesh Kumar Tyagi
Keyword(s):  
Lateral Root ◽  
Root Formation ◽  
Developmental Pathways ◽  
Stress Signaling ◽  
Oxygen Species ◽  
Lateral Root Formation ◽  
Rice Gene ◽  
Developmental Abnormalities ◽  
Biosynthesis Gene

Abstract Class-I TCP transcription factors are plant-specific developmental regulators. Inthis study, the role of one such rice gene, OsTCP19, in water-deficit andsalt stress response was explored. Besides a general upregulation by abioticstresses, this transcript was more abundant in tolerant than sensitive ricegenotypes during early hours of stress. Stress, tissue and genotype-dependentretention of a small in-frame intron in this transcript was also observed.Overexpression of OsTCP19 in Arabidopsis caused upregulation ofIAA3, ABI3 and ABI4 and downregulation of LOX2, andled to developmental abnormalities like fewer lateral root formation. Moreover,decrease in water loss and reactive oxygen species and hyperaccumulation of lipiddroplets in the transgenics contributed to better stress tolerance both duringseedling establishment and in mature plants. OsTCP19 was also shown to directlyregulate a rice triacylglycerol biosynthesis gene in transient assays. Genes similarto those up- or downregulated in the transgenics were accordingly found to coexpresspositively and negatively with OsTCP19 in Rice Oligonucleotide ArrayDatabase. Interactions of OsTCP19 with OsABI4 and OsULT1 further suggest itsfunction in modulation of abscisic acid pathways and chromatin structure. Thus,OsTCP19 appears to be an important node in cell signaling whichcrosslinks stress and developmental pathways.

scholarly journals PICKLE recruits RETINOBLASTOMA RELATED 1 to Control Lateral Root Formation in Arabidopsis

2019 ◽  
Author(s):  
Krisztina Ötvös ◽  
Pál Miskolczi ◽  
Peter Marhavý ◽  
Alfredo Cruz-Ramírez ◽  
Eva Benková ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Lateral Root ◽  
Promoter Activity ◽  
Root Formation ◽  
Auxin Signaling ◽  
Dependent Manner ◽  
Lateral Root Formation ◽  
Transcriptional Responses ◽  
Dividing Cells ◽  
Lateral Organ

AbstractLateral root (LR) formation is an example of plant post-embryonic organogenesis event. LRs are issued from non-dividing cells entering consecutive steps of formative divisions, proliferation and elongation. The chromatin remodeling protein PICKLE negatively regulates auxin-mediated LR formation through a mechanism that is not yet known. Here we show that PICKLE interacts with RETINOBLASTOMA-RELATED 1 (RBR1) to repress the LATERAL ORGAN BOUNDARIES-DOMAIN 16 (LBD16) promoter activity. Since LBD16 function is required for the formative division of LR founder cells, repression mediated by the PKL-RBR1 complex negatively regulates formative division and LR formation. Inhibition of LR formation by PKL-RBR1 is counteracted by auxin indicating that in addition to auxin-mediated transcriptional responses, the fine-tuned process of LR formation is also controlled at the chromatin level in an auxin-signaling dependent manner.

scholarly journals The expa1-1 mutant reveals a new biophysical lateral root organogenesis checkpoint

2018 ◽  
Author(s):  
Priya Ramakrishna ◽  
Graham A Rance ◽  
Lam Dai Vu ◽  
Evan Murphy ◽  
Kamal Swarup ◽  
...  
Keyword(s):  
Cell Division ◽  
Root System ◽  
Lateral Root ◽  
Root Formation ◽  
Lateral Roots ◽  
Lateral Root Formation ◽  
Asymmetric Cell Divisions ◽  
Cell Divisions ◽  
Root Organogenesis ◽  
Pericycle Cells

ABSTRACTIn plants, post-embryonic formation of new organs helps shape the adult organism. This requires the tight regulation of when and where a new organ is formed, and a coordination of the underlying cell divisions. To build a root system, new lateral roots are continuously developing, and this process requires asymmetric cell division in adjacent pericycle cells. Characterization of an expansin a1 (expa1) mutant has revealed a novel checkpoint during lateral root formation. Specifically, a minimal pericycle width was found to be necessary and sufficient to trigger asymmetric pericycle cell divisions during auxin-driven lateral root formation. We conclude that a localized radial expansion of adjacent pericycle cells is required to position the asymmetric cell divisions and generate a core of small daughter cells, which is a prerequisite for lateral root organogenesis.SIGNFICANCE STATEMENTOrgan formation is an essential process in plants and animals, driven by cell division and cell identity establishment. Root branching, where lateral roots form along the primary root axis, increases the root system and aids capture of water and nutrients. We have discovered that tight control of cell width is necessary to co-ordinate asymmetric cell divisions in cells that give rise to a new lateral root organ. While biomechanical processes have been shown to play a role in plant organogenesis, including lateral root formation, our data give new mechanistic insights into the cell size checkpoint during lateral root initiation.

scholarly journals PRH1 mediates ARF7-LBD dependent auxin signaling to regulate lateral root development in Arabidopsis thaliana

2019 ◽  
Author(s):  
Feng Zhang ◽  
Wenqing Tao ◽  
Ruiqi Sun ◽  
Junxia Wang ◽  
Cuiling Li ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factors ◽  
Root Development ◽  
Lateral Root ◽  
Lateral Roots ◽  
Auxin Signaling ◽  
Auxin Response ◽  
Cell Identity ◽  
Lateral Root Development ◽  
Lateral Organ

AbstractThe development of lateral roots in Arabidopsis thaliana is strongly dependent on signaling directed by the AUXIN RESPONSE FACTOR7 (ARF7), which in turn activates LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcription factors (LBD16, 18, 29 and 33). Here, the product of PRH1, a PR-1 homolog annotated previously as encoding a pathogen-responsive protein, was identified as a target of ARF7-mediated auxin signaling and also as participating in the development of lateral roots. PRH1 was shown to be strongly induced by auxin treatment, and plants lacking a functional copy of PRH1 formed fewer lateral roots. The transcription of PRH1 was controlled by the binding of both ARF7 and LBDs to its promoter region. An interaction was detected between PRH1 and GATA23, a protein which regulates cell identity in lateral root founder cells.Author SummaryIn Arabidopsis thaliana AUXIN RESPONSE FACTOR7 (ARF7)-mediated auxin signaling plays a key role in lateral roots (LRs) development. The LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcription factors (LBD16, 18, 29 and 33) act downstream of ARF7-mediated auxin signaling to control LRs formation. Here, the PR-1 homolog PRH1 was identified as a novel target of both ARF7 and LBDs (especially the LBD29) during auxin induced LRs formation, as both ARF7 and LBDs were able to bind to the PRH1 promoter. More interestingly, PRH1 has a physical interaction with GATA23, which has been also reported to be up-regulated by auxin and influences LR formation through its regulation of LR founder cell identity. Whether the interaction between GATA23 and PRH1 affects the stability and/or the activity of either (or both) of these proteins remains an issue to be explored. This study provides improves new insights about how auxin regulates lateral root development.

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