Cytokinin Response Factors (CRFs)

For more info about our services contact : help@bestpfe.com

Table of contents

Introduction
Plant embryonic development
Root growth and the root apical meristem
Root apical meristem morphology
Regulation of root apical meristem development
Lateral root development
Shoot apical meristem
The plant hormone auxin
The TIR1/AFB family of auxin receptors
The AUX/IAA repressors of auxin signalling
ARF transcription factors
ARF5
ARF6 and ARF8
ARF7 and ARF19
The plant hormone cytokinin
Cytokinin signalling pathway
Cytokinin Response Factors (CRFs)
Aims of the thesis
Chapter I: The tissue-specific expression of ARF activators during growth and development in the RAM and the SAM
Introduction
Results
ARF activators are differentially expressed in the root and the shoot
ARF7 expression in the RAM is regulated at the first intron
ARF activator distribution can be post-transcriptionally regulated
Discussion
Tissue-specific expression of ARF activators provides insights into specificity and redundancy of their functions in plant development
Expression patterns of ARF activators fits their well-studied functions and suggests new potential functions
Which elements are important to correctly recapitulate expression patterns of genes?
Post-transcriptional movement or degradation of ARF proteins provides another level of control in the auxin signaling pathway
Material and methods
Cloning and generation of ARF reporter lines
Root microscopy
Shoot microscopy
Supplementary information
Chapter II: Auxin Response Factor (ARF) activators are transcriptionally regulated by gene-specific repressor network
Introduction
Results
Yeast one-hybrid assay revealed an elaborate network of transcription factors controlling expression of ARF activators
The majority of the ARF activator transcriptional regulators act as repressors
Publically available databases can be used to further validate and explore the interactions
Mutants of the regulatory transcription factors indicate co-regulation of multiple ARF activators
Expression of the several transcription factors is regulated by auxin
Mutants of the regulatory transcription factors show auxin-related defects in root and shoot development
Discussion
Does the yeast one-hybrid gene regulatory network reflect in planta gene interactions?
ARF activator expression is predominantly regulated by transcriptional repressors
Regulation of ARF8 by multiple transcription factors might indicate its special significance in auxin signaling
Gene regulatory network motifs describe regulations that could be important during development
Expression of ARF activators is co-regulated in planta
Material and methods
Plant material
Y1H assay
Transient expression in Arabidopsis thaliana protoplasts
Expression analysis with qRT-PCR
Expression analysis of crosses between ARF transcriptional reporter lines and T-DNA mutants
Shoot phenotype analysis of the TF mutants
Root phenotype analysis of the TF mutants
Growth on NPA for shoot phenotype analysis
Supplementary information
Chapter III: Cytokinin Response Factor 10 regulates ARF7 expression to control plant development
Introduction
Results
Genetic characterization of the crf10 mutant
CRF10 is expressed in various tissues
crf10 mutant has an ARF7-dependant early senescence phenotype
crf10 mutant shows perturbation in hypocotyl response to blue light
crf10 mutant has a defect in root apical meristem morphology
Discussion
Is crf10-1 a loss-of-function mutant?
Does CRF10 act in cytokinin signaling?
CRF10 and ARF7 antagonistically control leaf senescence
CRF10 and ARF7 are acting together in hypocotyl phototropic response
CRF10 and ARF7 are involved in the maintenance of the root apical meristem
Material and methods
Plant material
Analysis of the conserved regions within the CRF10 protein across A. thaliana ecotypes
Genetic analysis of the crf10-1 mutant
Expression analysis with qRT-PCR
Cloning and generation of transgenic lines
Root microscopy
Shoot microscopy
Shoot phenotype analysis
Early senescence phenotype analysis
Chlorophyll measurement
Hypocotyl phototropism assay
Root phenotype analysis
Supplementary information
General discussion
ARF activators in control of plant development
ARF activators diversify and specialize during evolution
Component of auxin signaling pathway show specificity in expression patterns
ARF activator expression is predominantly regulated by gene repression mechanism
Auxin and cytokinin interactions regulate many aspects of plant development
Appendix
Overview of primers used in this study
List of primers
References