Project Number: 3611-21000-020-00
Project Type: Appropriated

Start Date: Apr 09, 2006
End Date: Apr 08, 2011

Objective:
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. Determine the mechanistic basis for limitations on photosynthetic performance including those imposed by agriculturally significant stresses. Establish the major features controlling the response of photosynthetic productivity in soybean to elevated atmospheric CO2, tropospheric ozone, and their interactions with drought, explore the bases for genetic variability in responses, and test potential transgenic amelioration strategies. Sub-objective 3.5 to the 416/417 as ¿Use genomic and metabolomic data obtained at the plant community level to interpret the interaction of elevated CO2 and drought on the structure and function of soybean agrosystem.¿

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. Investigate the biochemical basis of the light regulation of Rubisco/activase in species that lack the redox-regulated large isoform of activase. Further elucidate the mechanism of the interaction between Rubisco and activase. 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. 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 O3 with drought on soybean performance. Determine if growth at elevated CO2 enhances or ameliorates oxidative stress.