Watson, Bonnie S. , Urbanczyk-Wochniak, Ewa , Lei, Zhentian , Bedair, Mohamed , Sumner, Lloyd W. .
Spatially Resolved Metabolomics and Proteomics of Medicago truncatula Border Cells and Root Tips.
Plant root tips, composed of apical meristem and root cap, produce thousands of differentiated border cells which separate from the root. Border cells are more than by-products of root cap growth as they provide a biotic boundary fundamental in rhizosphere modifications, ecological interactions, and plant defense. Specifically, border cells attract and immobilize nematodes, produce defense structures in response to fungi, bind and repel bacteria, and increase mucilage production in response to aluminum. Despite these critical roles, little is known about the biochemistry of these specialized and spatially resolved cells. We will report on an integrated metabolomics and proteomics approach used to systematically evaluate basal differences between Medicago truncatula border cells and root tips and their temporal responses to the pathogenic fungus Phymatotrichum omnivorum (root rot). GC/MS and UPLC/MS have been utilized to probe metabolic differences between root tips and border cells for primary and secondary metabolites, respectively. To date, secondary metabolites found at higher and statistically significant levels (p<0.05) in border cells include pyrethrin, phenolics, fatty acids, and yet unidentified compounds. Secondary metabolites found at increased and significant levels in root tips include other phenolics and fatty acids, saponins, and unknowns. Preliminary results show that border cells exposed to P. omnivorum contain higher levels of numerous compounds, including several saponins. Two-dimensional electrophoresis coupled to LC/MS/MS is being used to identify proteins differentially displayed in border cells. Fundamental biochemical differences that characterize border cells and influence their role in plant-microbe interactions will be discussed.
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1 - Samuel Roberts Noble Foundation, Plant Biology, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
2 - Samuel Roberts Noble Foundation, Plant Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM