Degree Type

Dissertation

Date of Award

2019

Degree Name

Doctor of Philosophy

Department

Genetics, Development and Cell Biology

Major

Genetics

First Advisor

Steve A. Whitham

Second Advisor

Jo Anne Powell-Coffman

Abstract

Abstract: FERONIA (FER), a plasmamembrane-localized receptor kinase plays vital roles in plant growth development and stress responses. In the past decade, ligands, co-receptors, and many signaling components have been identified to shine light on the regulatory mechanisms. However, a comprehensive signaling network underlying FER-mediated diverse processes is still lacking.

To this end, and also to facilitate the discovery of novel FER-mediated pathways, we carried out transcriptomic, proteomic and phosphoproteomic analyses. From the transcriptome analysis, we discovered that FER is a major negative regulator of plant hormone Jasmonic acid (JA) signaling. Further genetics, biochemistry and cell biology experiments demonstrate that FER phosphorylates and destabilizes MYC2 to inhibit JA signaling and MYC2-mediated host plant susceptibility, which establishes FER as a positive regulator in bacterial pathogen defense. RALF23, a rapid alkalization factor and a peptide ligand for FER, functions through FER to negatively contribute to bacterial defense.

The proteome analysis validates previous findings such as negative regulation of FER on JA, and supports a role of FER in maintaining nutrient and energy homeostasis. The phosphoproteomics data analysis identified a group of transcription factors that potentially carry out diverse functions. The omics data has also revealed novel FER-mediated processes.

The dissertation research establishes RALF23-FERONIA-MYC2, a ligand-receptor-transcription factor signaling module, as one of the underlying mechanisms for FER-mediated bacterial defense. Further studies on the newly identified candidate substrate transcription factors and novel pathways will broaden our understanding on how FERONIA, a plasmamembrane-localized receptor kinase, regulates plant growth development and stresses responses.

Copyright Owner

Hongqing Guo

Language

en

File Format

application/pdf

File Size

188 pages

Available for download on Sunday, April 18, 2021

Included in

Genetics Commons

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