Church, Jeffrey , Seebauer, Juliann , Schneerman, Martha , Below, Frederick , Moose, Stephen .
Genetic Control of the Carbon-Nitrogen Balance in Maize Leaves.
Primary assimilation of nitrogen in higher plants is a complex process that often competes with other metabolic systems for resources derived from photosynthesis. In maize, optimal control of the C4 photosynthesis and N assimilation reactions is especially important in the vegetative source tissues, which supply crucial resources to the developing kernels and are important regulators of high yield. We examined the effects of high (200 ppm) and low (14 ppm) N supply on the leaves of B73 and Illinois High Protein (IHP), a genotype that accumulates high levels of total plant N and the highest known concentrations of seed protein. To control N responses, we grew IHP and B73 plants to the 8-leaf stage in a previously developed hydroponics system. Initial characterizations confirmed changes in chlorophyll concentration, total photosynthesis, whole-plant N content, and total biomass, where IHP accumulated significantly more root and shoot N than B73, although B73 exhibited greater biomass at both N rates. Leaf samples from these plants were characterized by microarray analyses, qPCR expression validations, enzyme assays, western blots and metabolite profiles. Our experiments to date suggest that a relationship between photosynthetic carbon shuttling and asparagine, both in its synthesis and catabolism, is key in determining how maize leaves respond to N.
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1 - University of Illinois, Urbana-Champaign, Crop Sciences, 1201 W. Gregory Drive, 389 ERML, Urbana, IL, 61801, USA
2 - University of Illinois, Crop Sciences
nitrogen and carbon metabolism
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM