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Strobilurin fungicide secondary plant stress alleviation effects

Matthew A Pedersen, University of Nebraska - Lincoln


The Poaceae or grass family is among the most land covering and rapidly regenerating plant families on the planet. Initial interests outlined in this dissertation were characterizing supina bluegrass and bermudagrass health promoting compounds (Chapter 1). Seedlings of both species contained abundant levels of phenolic compounds comparable or higher to phenolic-rich fruits and vegetables. Phenolic and flavonoid content changed significantly during the first month of growth, offering an abundant, renewable and novel nutraceutical resource. While investigating this, we also became interested in evaluating the fungicide azoxystrobin’s plant stress alleviation potential. Both problems were thus investigated tandemly, as antioxidant systems may play a large role in the azoxystrobin plant response. ^ Fungicides and plant growth regulators can impact plant growth outside of their effects on fungal pathogens. Strobilurins, such as azoxystrobin, are a relatively new class of fungicides that reduce respiration by inhibiting the mitochondrial protein cytochrome bc1. Strobilurins are gaining interest in their ability to delay leaf senescence and preserve oxidative balance, which, in turn, can lead to increased yields for cereal grain crops, or increased greenness and quality of high input turfgrass stands. Although azoxystrobin is an inhibitor of mitochondrial oxygen uptake, information remains limited as to whether they are able to modify other mitochondrial constituents and what downstream plant effects occur.^ Fourier transform mid-infrared spectroscopy (FT-mIR) offers a high sample throughput method to comparatively and qualitatively evaluate the effects of exogenously added compounds in creeping bentgrass. After proving FT-mIR was a powerful tool for discriminating isolated and chemically treated mitochondria (Chapter 2), Ft-mIR was used to monitor significant biochemical changes in whole plants (Chapter 3). Collected data proved that azoxystrobin had a large impact on the metabolite profile of creeping bentgrass, affecting leaf tissue protein, lipid, polysaccharide, carbohydrate and DNA. ^ Lastly, phytohormone, phenolic, flavonoid and thiobarbituric acid reactive species content in fungicide-treated creeping bentgrass and bermudagrass was determined in the presence and absence of heat stress (Chapter 4). Results demonstrated that increased levels of cytokinins and phenolic components in heat stressed plants may contribute to increased thermo-tolerance and preserved plant health.^

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Recommended Citation

Pedersen, Matthew A, "Strobilurin fungicide secondary plant stress alleviation effects" (2016). ETD collection for University of Nebraska - Lincoln. AAI10245880.