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PhD Exit Seminar – Heather Wheeler- Monday, November 20th, 2017
November 20, 2017 @ 2:00 pm - 3:00 pm
PhD Exit Seminar
Monday November 20th, 2:05 pm – Ramsay Wright Building, Room 432
Heather Wheeler (Campbell lab)
Cellulose Biosynthesis has Extensive Impacts on Overall Plant Metabolism, Which are Mediated in Part by Pentaglycine, a Novel Peptide Signal
As sessile organisms, plants must continually adapt to their environment. In order to allocate resources appropriately, plants have elaborate pathways in place for detecting and responding to changes in their environment and the integrity of their cells, particularly the cell wall. Cellulose is the major component of plant cell walls and a major sink for carbon in the plant body. Cellulose is central to plant structure and function, imparting sufficient strength and resilience to withstand turgor pressure, negative pressure, and gravity. It was therefore hypothesized that plants have broad, far-reaching metabolic responses to cellulose disruption.
To uncover the response to cellulose perturbation at the metabolic level, Comprehensive Multiphase-Nuclear Magnetic Resonance (CMP-NMR) was used in combination with a mutant analysis and pharmacological experimentation. This approach revealed several metabolic impacts of cellulose perturbation that were previously unknown, including decreased metabolism of seed lipid stores during germination, increased production of methanol and ethanol in seedlings, and the presence of pentaglycine in seedlings.
Another line of investigation revealed that a compound or compounds present in the cellulose synthase mutant eli1 was able to increase lignin content of wild-type seedlings. Pentaglycine had a similar effect on WT seedlings. Taken together with the increased abundance of pentaglycine in eli1 seedlings, the results suggest that pentaglycine is in part responsible for the increased lignin content that characterizes cellulose synthase mutants. A model is presented that integrates these components into a signaling pathway to monitor and respond to perturbation in the cellulosic component of cell wall integrity.