Discovery and engineering of metabolite-based defense mechanisms in plants
Abstract/Contents
- Abstract
- Plants have developed intricate biochemical systems to detect and respond to pathogens in the environment. Improved fundamental understanding of these processes will allow us to engineer plants for improved pathogen defense, ultimately improving yields in agriculture. In this work, we discovered a new metabolite, N-hydroxy-pipecolic acid (NHP), that we found is integral to the plant defense response systemic acquired resistance (SAR). SAR is a whole-plant response that is induced at a pathogen infection site and leads to broad-spectrum disease resistance in uninfected tissues. Treatment of plants with NHP provided enhanced defense against bacterial pathogens, but not without fitness costs in certain contexts. This inability of plants to balance defense and growth led us to investigate the role of a glycosylated derivative of NHP that accumulates in Arabidopsis. We found a dedicated glycosyltransferase for NHP that is also biochemically active on the core plant defense hormone salicylic acid. We provide evidence that this enzyme acts to convert these biochemically active small molecules into their glucose conjugates to temper immune responses. Next, we discovered that several important crop species produce and respond to NHP. With this knowledge, we used metabolic engineering to overproduce NHP in tomato plants and showed that it could improve defense against a bacterial pathogen. To conclude, we provide a framework for using synthetic biology and directed evolution to engineer plant receptor systems for expanded detection and defense capabilities. This work establishes the metabolic basis for SAR in Arabidopsis and provides new insight into how plants regulate small molecule biosynthesis to tailor responses to environmental stimuli.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Holmes, Eric Christopher |
|---|---|
| Degree supervisor | Sattely, Elizabeth |
| Thesis advisor | Sattely, Elizabeth |
| Thesis advisor | Mudgett, Mary Beth, 1967- |
| Thesis advisor | Spormann, Alfred M |
| Thesis advisor | Swartz, James R |
| Degree committee member | Mudgett, Mary Beth, 1967- |
| Degree committee member | Spormann, Alfred M |
| Degree committee member | Swartz, James R |
| Associated with | Stanford University, Department of Chemical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Eric Christopher Holmes. |
|---|---|
| Note | Submitted to the Department of Chemical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/zm335kf0937 |
Access conditions
- Copyright
- © 2021 by Eric Christopher Holmes
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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