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ORCID
https://orcid.org/0000-0002-2290-3249
Access Type
Open Access Thesis
Document Type
thesis
Degree Program
Microbiology
Degree Type
Master of Science (M.S.)
Year Degree Awarded
2021
Month Degree Awarded
September
Abstract
Eutypa dieback, one of several grapevine trunk diseases (GTDs), is of serious concern to the grape industry globally. This disease is caused by the fungus Eutypa lata but it is often seen in consortia growth with Phaeoacremonium minimum and Phaeomoniella chlamydospora. It is vital to understand the mechanisms for how this disease functions to develop control measures to combat it. Brown rot fungi are able to use a complex of low molecular weight (LMW) metabolites to induce a Fenton reaction to deconstruct woody tissue. These metabolites are part of a chelator mediated Fenton (CMF) chemistry that produces reactive oxygen species that are capable of depolymerizing wood polymers. We propose that a mechanism similar to CMF chemistry may be occurring in grapevine trunk disease pathogens. This thesis investigates how LMW metabolites produced by the fungi contribute to the disease and decay progression in GTDs. Research on Mite control in the laboratory with abamectin was also investigated, as research in this area was required when mites infested our fungal cultures and suitable laboratory controls were not available. Research on the GTD fungi was initiated by first examining whether metabolites produced by the three fungi can function in a manner to promote reactions like the CMF system. We separated and identified specific metabolites that potentially could contribute to CMF chemistry. We found that all three GTD fungi were able to produced LMW metabolites that promoted CMF chemistry, and we hypothesized that this mechanism contributes to processes leading to tissue necrosis in grapevine trunk wood. To explore the development of effective control measures based on this newly discovered mechanism for pathogenesis, we also explored the use of antioxidant/chelator compounds, BHA and BHT, in the control of the consortia fungi. Biocontrol organisms, Bacillus subtilis and Trichoderma atroviride, that produce antioxidants were also tested as biocontrols against the fungi involved in Eutypa Dieback disease. We found that BHA was highly effective in inhibiting fungal growth for all three fungi at concentrations higher than 0.5mM, and both B. subtilis and T. atroviride proved to be effective biocontrol agents in inhibiting E. lata, P. minimum, and P. chlamydospora.
DOI
https://doi.org/10.7275/24014076.0
First Advisor
Barry Goodell
Second Advisor
Elsa Petit
Third Advisor
Jody Jellison
Fourth Advisor
Reuben Shipway
Recommended Citation
Sebestyen, Dana, "The Role of Low-Molecular Weight Fungal Metabolites in Eutypa Dieback Grapevine Trunk Disease" (2021). Masters Theses. 1117.
https://doi.org/10.7275/24014076.0
https://scholarworks.umass.edu/masters_theses_2/1117
Included in
Agricultural Science Commons, Microbial Physiology Commons, Other Microbiology Commons, Plant Pathology Commons