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United States Department of Agriculture

Agricultural Research Service

Research Project: IDENTIFYING AND MANIPULATING DETERMINANTS OF PHOTOSYNTHATE PRODUCTION AND PARTITIONING

Location: Global Change and Photosynthesis Research Unit

Project Number: 3611-21000-024-00
Project Type: Appropriated

Start Date: Oct 01, 2010
End Date: May 30, 2013

Objective:
Objective 1: Define the key regulatory elements controlling photosynthate partitioning and nitrate assimilation and their interactions; develop and begin to test strategies to modify those processes for agricultural purposes. Objective 2: Determine the mechanistic basis for limitations on photosynthetic performance including those imposed by agriculturally significant stresses. Objective 3: Establish the major features controlling the response of photosynthetic productivity in soybean and corn to elevated atmospheric CO2, tropospheric ozone, and their interactions with drought and temperature, explore the bases for genetic variability in responses, and test potential transgenic amelioration strategies. Objective 4: Determine the environmental impacts of land cover change associated with alternative bioenergy crops.

Approach:
Investigate isoform specificity for nitrate reductase (NR) posttranslational modification in vivo, and elucidate the impact of 14-3-3 binding on NR protein degradation. Localize the membrane binding site(s) on sucrose synthase and identify factors that may control the interaction. Use high-resolution spatial and temporal analysis of leaf growth to identify specific areas where leaf growth is occurring. Determine the biochemical factors responsible for the lower activation state of Rubisco, at high temperatures and test potential transgenic amelioration strategies. Further elucidate the role of Rubisco activase in thermal sensitivity/tolerance. Determine the biochemical basis for the "Green Seed Problem" of canola. Perform metabolite analysis of growing leaves under elevated CO2 and O3 to identify key components that may be involved in controlling growth. Determine the factors that lower the activation state of Rubisco under sink- and/or N-limited conditions, which are often encountered when plants are grown under high CO2. Explore the interaction of elevated CO2 with drought on soybean performance. Explore the interaction of elevated CO2 with temperature on soybean and corn performance. Determine if growth at elevated CO2 enhances or ameliorates oxidative stress. Determine the impact of land cover change from row crops to perennial grasses on hydrological cylce and carbon biosequestration.

Last Modified: 8/30/2014
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