Skip to Main Content
Frequently Asked Questions
Submit an ETD
Global Search Box
Need Help?
Keyword Search
Participating Institutions
Advanced Search
School Logo
Files
File List
PSherwood PhD dissertation 2014 1a full convert.pdf (7.01 MB)
ETD Abstract Container
Abstract Header
Biochemical Mechanisms of Resistance and Susceptibility in the Pinus nigra - Diplodia sapinea Pathosystem
Author Info
Sherwood, Patrick William
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1408640310
Abstract Details
Year and Degree
2014, Doctor of Philosophy, Ohio State University, Environment and Natural Resources.
Abstract
To counter the constant barrage of biotic threats that limit their survival, plants have evolved complex perception and signaling networks that allow for the detection of attackers and the induction of appropriate defensive responses. One important aspect of defense is the production of antimicrobial metabolites, which make the plant less habitable to invading pathogens. These metabolites can be present constitutively, or produced after a threat has been detected, including systemically in a phenomenon known as systemic induced resistance (SIR), whereby tissues distal to an initial infection possess greater inherent resistance to subsequent attacks. This phenomenon is well established in herbaceous model plants, but its occurrence in trees and other non-traditional model plants are comparatively less understood, so new model systems are needed to understand how the SIR state is reached in trees. Therefore, a major focus of this research was to investigate the basis of SIR in the Austrian pine (Pinus nigra Arnold) – Diplodia sapinea (Fr.) Fuckel pathosystem, for which SIR has been previously demonstrated and linked to the accumulation of phenolic metabolites in the systemic tissues. The central objective of this research was to evaluate the role of phenolics in SIR, by examining their antifungal properties, characterizing the temporal spatial patterns of their induction, and determining the influence of resource availability on their function in resistance. A corollary objective was to study the effects of water stress on resistance properties. It was discovered that while phenolic compounds previously implicated in SIR possess potent antifungal properties in vitro, their induction in planta is highly variable, and often not associated with the SIR phenotype. Furthermore, constitutive phenolic metabolism is only moderately responsive to nutrient availability, while induced phenolics are even less affected by differences in resource levels. Investigations into the signaling mechanisms revealed that induction of SIR is independent of phloem connectivity between the site of induction and challenge, suggesting that other transmission avenues are available to trees. Lastly, drought stress was shown to significantly weaken plant resistance levels through a combination of stress induced changes in host physiology that predispose the plants to infection, and pathogen exploitation of these changes. Together this research has improved our understanding of the role of phenolic defenses in pines and furthered the development of the Austrian pine – Diplodia sapinea pathosystem, so that new avenues of plant-microbe interactions can be investigated.
Committee
Pierluigi Bonello, Dr. (Advisor)
Pages
303 p.
Subject Headings
Plant Pathology
Keywords
Pinus nigra, induced resistance, phenolic metabolites, Diplodia sapinea, drought stress, fertilization
Recommended Citations
Refworks
EndNote
RIS
Mendeley
Citations
Sherwood, P. W. (2014).
Biochemical Mechanisms of Resistance and Susceptibility in the Pinus nigra - Diplodia sapinea Pathosystem
[Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408640310
APA Style (7th edition)
Sherwood, Patrick.
Biochemical Mechanisms of Resistance and Susceptibility in the Pinus nigra - Diplodia sapinea Pathosystem.
2014. Ohio State University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1408640310.
MLA Style (8th edition)
Sherwood, Patrick. "Biochemical Mechanisms of Resistance and Susceptibility in the Pinus nigra - Diplodia sapinea Pathosystem." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408640310
Chicago Manual of Style (17th edition)
Abstract Footer
Document number:
osu1408640310
Download Count:
666
Copyright Info
© 2014, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.