Type
Text
Type
Dissertation
Advisor
Advisors: Miller, Lisa M.; Boon, Elizabeth; French, Jarrod B.; Tappero, Ryan
Date
2018-01-01
Keywords
FTIR spectroscopy and Imaging, Chemistry, Botany, Mycorrhiza, Plant imaging, Rhizosphere, Symbiotic fungus, X-ray spectroscopy
Department
Department of Chemistry | Dissertation
Language
en
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/78317
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
The mechanistic links between plants and growth promoting micro-organisms in an eco-system involved in the production of biomass are currently very poorly understood. Observing the nutrient changes in the rhizosphere is a key step to understanding the molecular dynamics involved in these symbiotic interactions and nutrient pathways that facilitate plant growth. To study such a nutrient flow, a new application of Fourier Transform Infrared Imaging (FTIRI) was developed that entailed growing Populus tremuloides seedlings on a thin, nutrient-enriched Phytagel matrix that allows pixel to pixel measurement of the distribution of nutrients, in particular, nitrate and ammonium and sucrose added as a carbon source in the rhizosphere. For quantification of the nitrate concentration in the rhizosphere of experimental plants, a calibration curve was generated that gave the nitrate concentration at each pixel in the measured chemical images. The chemical images collected from the poplar rhizosphere showed a higher nitrate concentration present in regions where the fungus, Laccaria bicolor, was detected suggesting sequestration from the media toward the plant root. In the control experiments without Laccaria bicolor, the nitrate concentration remains mostly constant while the experiments with the fungus indicate varying gradients in the nitrate concentration. These gradients may facilitate the uptake and transport of nitrate across the fungi to the plant. To study the proteins involved in the nitrogen transport in this symbiotic relationship, x-ray fluorescence microscopy was utilized to measure proteins tagged with lanthanide-binding tags (LBTs), which are GFP-like analogs of minimal size. LBTs are short peptide sequences comprised of 15-20 naturally occurring amino acids that bind trivalent lanthanide ions with a nano-molar affinity. Two and three-dimensional x-ray images revealed that this method is suitable for identifying single proteins. This ability to monitor nutrient changes with other micro-organisms in the rhizosphere and the proteins responsible for the nutrient transport are key steps to understanding these symbiotic associations which facilitate plant growth which can provide useful information for growing plants sustainably by taking advantage of already existing plant-microbe relationships. | 128 pages
Recommended Citation
Victor, Tiffany Whitney, "Understanding Nitrogen Uptake in the Rhizosphere of a Mycorrhizal Fungus and Plant System" (2018). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 3811.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/3811