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Understanding Gene Regulatory Networks Mediating Ethylene Response in Arabidopsis Roots Using Bioinformatic and Genetic Approaches

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abstract
Hormones frequently regulate development by receptor-mediated networks of transcriptional responses. The plant hormone ethylene remodels the architecture of roots of Arabidopsis thaliana by reducing root elongation and lateral root initiation, while stimulating formation and elongation of root hairs. This thesis explores the gene regulatory networks which control ethylene’s effects on root development. A time course transcriptomic analysis reveals root-specific transcriptional responses to the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), clustering these transcripts into groups with consistent temporal response. To identify transcriptional networks that control ethylene responses a method was developed to search these clusters for TFs that have enriched binding to these groups of genes, revealing new TFs not previously linked to ethylene signaling. A meta-analysis comparing three prior publications reveals a consistently regulated group of transcripts that respond to both ACC and ethylene in light- and dark-grown seedlings, as well as transcripts that show context-specific response. Arabidopsis has five ethylene receptors and the function of these in controlling root development was resolved using gain-of-function and loss-of-function mutant alleles, revealing a central role of ETR1 in controlling ethylene responses in roots. The transcriptional network downstream of the ETR1 receptor was identified through an RNA-Seq analysis of receptor gain-of-function and loss-of-function alleles, revealing a group of ETR1-dependent transcripts that may drive the ETR1 root developmental responses. Together, these chapters provide insight into the receptor and gene regulatory network by which ethylene transforms root development.
subject
ethylene
ETR1
gene regulatory networks
hormone signaling
root development
transcription factors
contributor
Harkey, Alexandria Faith (author)
Muday, Gloria K (committee chair)
Miller, Lance D (committee member)
Howard, Timothy D (committee member)
Turkett, William H (committee member)
Zhang, Ke (committee member)
date
2020-05-29T08:35:49Z (accessioned)
2020 (issued)
degree
Molecular Genetics & Genomics (discipline)
2022-05-28 (liftdate)
embargo
2022-05-28 (terms)
identifier
http://hdl.handle.net/10339/96808 (uri)
language
en (iso)
publisher
Wake Forest University
title
Understanding Gene Regulatory Networks Mediating Ethylene Response in Arabidopsis Roots Using Bioinformatic and Genetic Approaches
type
Dissertation

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