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CC BY V4.0, Open Access
Dissertation
CLOVER ALL OVER: INVESTIGATING WILD TRIFOLIUM MANAGEMENT OF BACTERIAL SYMBIONTS
Washington State University
Doctor of Philosophy (PhD), Washington State University
05/2025
DOI:
https://doi.org/10.7273/000007365
Abstract
Legumes (Fabaceae) can develop symbiotic relationships with nitrogen fixing bacteria, rhizobia, to meet their need for nitrogen. Legumes recruit rhizobia from soil, house them in root organs called nodules, provide the bacteria with carbon compounds and receive biologically available nitrogen in return. The rhizobial transition from free living bacteria to host associated, nitrogen-fixing bacteroids is poorly understood. One mechanism by which the host manipulates bacterial development uses members of a large family of small antimicrobial peptides called Nodule-specific Cysteine-Rich (NCR) peptides. These are plant proteins exclusively expressed in the nodule and share a 4 or 6 cysteine residue motif. The genes and their associated peptides differ in number, sequence, and function across the legumes. Here we present a literature review of NCR peptides across leguminous species to aid in the understanding of legume host control of bacteria inside nodule tissue. Next, we present greenhouse experiment investigating the influence of non-rhizobia, nodule associated bacteria (NAB) on the fitness alignment of host and symbiont. We find that nodule associated bacteria do not have significant consequences for plant or bacterial fitness but can alter the alignment between host and symbiont fitness. Finally, we present assembled and annotated genomes of five Trifolium species and a summary of each species NCR gene family as an exploration of species-specific changes to NCR gene family structure. The NCR gene family in Trifolium is smaller than that in the model legume Medicago truncatula and similar across the species investigated.
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Details
- Title
- CLOVER ALL OVER
- Creators
- Ashton A. Eaker
- Contributors
- Maren L Friesen (Chair)Michael L Kahn (Committee Member)Stephen P Ficklin (Committee Member)Stephanie S Porter (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Program in Molecular Plant Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 118
- Identifiers
- 99901220475501842
- Language
- English
- Resource Type
- Dissertation