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http://hdl.handle.net/11375/20029
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DC Field | Value | Language |
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dc.contributor.advisor | Cameron, Robin K. | - |
dc.contributor.advisor | Weretilnyk, Elizabeth A. | - |
dc.contributor.advisor | Daniel, Juliet | - |
dc.contributor.author | Carella, Philip | - |
dc.date.accessioned | 2016-08-03T19:06:51Z | - |
dc.date.available | 2016-08-03T19:06:51Z | - |
dc.date.issued | 2016 | - |
dc.identifier.uri | http://hdl.handle.net/11375/20029 | - |
dc.description.abstract | Systemic acquired resistance (SAR) is a defense response induced by an initial localized infection that leads to the generation of long-distance immune signals that travel to distant leaves to provide enhanced resistance to subsequent infections. The lipid transfer protein (LTP) DEFECTIVE IN INDUCED RESISTANCE1 (DIR1) travels via the phloem from induced to distant leaves during SAR and may chaperone several long-distance signal candidates. In this thesis, the role of DIR1 during SAR is explored by examining the route of DIR1 movement, investigating the conservation of DIR1 structure and function, and by identifying DIR1-interacting proteins. I demonstrate that Arabidopsis plant lines with restricted cell-to-cell movement through plasmodesmata are negatively impacted in long-distance DIR1 movement, suggesting that cell-to-cell movement is important for DIR1 to access distant leaves. To elucidate the molecular function of DIR1, orthology analysis was performed with putative DIR1 orthologs. Structurally important amino acid residues that contribute to the hydrophobicity of the LTP cavity were identified, supporting the idea that DIR1 binds a hydrophobic ligand during SAR. RNAi-mediated knockdown of the DIR1 paralog DIR1-like did not impact the SAR response, supporting the idea that DIR1- like plays a lesser role in SAR. In addition, targeted protein-protein interaction assays determined that LTP1 and LTP2 interact with DIR1, and SAR phenotypic analysis of an ltp2-1 mutant supported a role for LTP2 in SAR. Lastly, a comparative proteomics approach identified several proteins with differential abundance in phloem exudates collected during the induction of SAR. Of these proteins, m-type thioredoxins, a major latex protein-like protein, and the UV-B photoreceptor UVR8 were essential for the manifestation of SAR. Together, these data provide insight into DIR1 function by identifying the importance of cell-to-cell movement through plasmodesmata, the DIR1 hydrophobic cavity, and DIR1-interacting proteins for DIR1-mediated SAR. In addition, this work identifies new phloem-localized proteins that contribute to the SAR response, providing fundamental knowledge on protein composition within the phloem during biotic stress. | en_US |
dc.language.iso | en | en_US |
dc.subject | Plant Pathology | en_US |
dc.subject | Phloem | en_US |
dc.subject | Lipid Transfer Protein | en_US |
dc.subject | Systemic Acquired Resistance | en_US |
dc.title | EXPLORING THE ROLE OF DIR1 AND OTHER PHLOEM-MOBILE PROTEINS DURING SAR | en_US |
dc.type | Thesis | en_US |
dc.contributor.department | Biology | en_US |
dc.description.degreetype | Dissertation | en_US |
dc.description.degree | Doctor of Philosophy (PhD) | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Carella_Philip_July2016_PhD.pdf | Main Document | 32.45 MB | Adobe PDF | View/Open |
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