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The Induction and Photoregulation of Flavonoid Synthesis in Poa trivialis L. and its Impact on Salt Stress Sensitivity

Petrella, Dominic Paul
http://rave.ohiolink.edu/etdc/view?acc_num=osu1490679768554881

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Horticulture and Crop Science.
Flavonoids are a group of plant secondary metabolites that are in great demand for their health promoting properties, and specific flavonoids, like anthocyanins, are in demand because of their potential as natural dyes. However, sources of these metabolites are limiting, and new alternative plant species are needed to meet industry needs. Turfgrasses are a group of monocots that could serve as biological production systems due to their unique anatomy. These plants, however, do not naturally produce large quantities of flavonoids, but some turfgrass species like rough bluegrass (Poa trivialis L.) exhibit greater flavonoid quantities relative to other turfgrasses. Flavonoids, in general, are highly regulated by light, and the application of wavelength-specific light treatments to rough bluegrass could increase flavonoid content to acceptable levels. While flavonoids are used in consumer products for their color or anti-oxidant properties, the function of flavonoids in plants is still not completely understood. However, flavonoids have been shown to interact with the transport and metabolism of the phytohormone auxin, and flavonoids may therefore act as modulators of plant tropic growth. Halotropism, a recently defined tropic growth response, occurs following exposure to a directional salt stress, and roots will bend/grow away from the area of high salt concentration due to changes in auxin transport and metabolism. For turfgrasses, the use of re-claimed water as an alternate irrigation strategy is on the rise due to restrictions on fresh water irrigation, but re-claimed water can contain large concentrations of salt. Salt exclusion and sequestration are well-understood mechanisms of salt tolerance. However, turfgrass seedlings may exhibit halotropic growth as an additional mechanism to evade saline soil, and flavonoids may modulate this growth response. Our objectives were to first determine what wavelengths of light regulate flavonoid metabolism in the turfgrass species rough bluegrass, second to determine if the trait for flavonoid upregulation exists in natural populations of this species, and last to evaluate the impact of light and flavonoid up-regulation on halotropic growth in rough bluegrass. My results have shown that blue wavelengths of light are responsible for regulating flavonoid synthesis in rough bluegrass, and red light can modulate flavonoid synthesis in the presence of blue light. This ability to increase flavonoid concentrations under blue light treatment, however, has only been observed in production cultivars of rough bluegrass and in accessions originating from Germany. When exposed to a salt gradient, rough bluegrass exhibits halotropic growth at NaCl concentrations greater than 350 mM. My results also show that blue light modulates halotropism; blue light increases the degree to which roots bend away from NaCl. However, exposure to red light results in the loss of halotropism. High pressure liquid chromatography (HPLC) profiles show that blue light significantly increases both flavonoid and anthocyanin content in root tissue, while white light treated roots only exhibit trace amounts of flavonoids. In red light treated roots, flavonoids are below the limit of detection, and display a secondary metabolite profile similar to pre-treatment samples.
David Gardner (Advisor)
Joshua Blakeslee (Advisor)
James Metzger (Committee Member)
Anne Dorrance (Committee Member)
330 p.
Agriculture; Physiology; Plant Biology; Plant Sciences

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Citations

  • Petrella, D. P. (2017). The Induction and Photoregulation of Flavonoid Synthesis in Poa trivialis L. and its Impact on Salt Stress Sensitivity [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1490679768554881

    APA Style (7th edition)

  • Petrella, Dominic. The Induction and Photoregulation of Flavonoid Synthesis in Poa trivialis L. and its Impact on Salt Stress Sensitivity . 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1490679768554881.

    MLA Style (8th edition)

  • Petrella, Dominic. "The Induction and Photoregulation of Flavonoid Synthesis in Poa trivialis L. and its Impact on Salt Stress Sensitivity ." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1490679768554881

    Chicago Manual of Style (17th edition)

osu1490679768554881
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This open access ETD is published by The Ohio State University and OhioLINK.