2011 Annual Report
1)unless soybean can be adapted, both water use efficiency and yield of soybean will continue decline as ozone levels in soybean growing areas of the US increase over the next half century;.
2)reduced water use results in an increase in soybean canopy temperatures and ground level heating that is not included in current general circulation models for predicting future environments and thus may be underestimating warming that is not the result of greenhouse gases. 4. The new generation of bioenergy crops remove carbon from the atmosphere and sequester a portion of it in soil thereby reducing the green house carbon footprint for bioenergy. The primary goal of bioenergy crops is to offset the use of fossil fuels and thereby reduce the amount of carbon and other pollutants that are emitted in energy production. An important concern in converting land from a current purpose to the new purpose of growing bioenergy crops is that this land use change could result in carbon emissions from the soils into the atmosphere and negate the short-term gains of growing biofuels to replace fossil fuels. Work conducted by ARS scientists at Urbana, IL showed that when converting from traditional corn and soybean row crop agriculture to growing perennial grasses species such as Miscanthus and switch grass, the improvement of the carbon foot print is immediate whereby perennial grasses sequester carbon even during the first few years of establishment. The impact of this accomplishment is that it removes significant uncertainty about the carbon balance of growing second-generation bioenergy crops in the US. 5. Deactivation of receptors; a new mechanism in understanding how crop plants sense and respond to changing environments. Plants have a large family of "receptors" that receive signals from the environment, which are instrumental in a plant's ability to respond appropriately to a particular change in its environment; for example to sense and respond to a pathogen or to sense and respond to change in water availability. Many of these receptors recognize specific plant hormones that are produced in response to specific changes in the environment. Protein receptor kinases are an important group of receptors that recognize plant hormones. Some receptor kinases are turned on when they come in contact with the appropriate hormone and initiated a programmed signaling cascade that eventually results in the physiological response of the plant to the environmental change. While much is known in detail about how these protein kinase receptors are turned on; rather little is known about how they are turned off which is just as important in mounting an appropriate physiological response. Work conducted by ARS scientists at Urbana, IL showed that the modification of a specific amino acid on some receptor kinases by phosphorylation turns off the response. The impact of this research is that it for the first time provides a potential mechanism by which we can manipulate the signaling cascade to fine tune the response to, for example, enhance pathogen resistance. 6. Greater than expected yield stimulation of cassava (Manihot esculenta) by future carbon dioxide [CO2] levels. The potential for tuber crops such as cassava, yams and potatoes to enhance food security in the future is underestimated. In tuber crops there is the potential for a much higher ratio of edible to non-edible components than in above ground grain and bean crops such as rice, wheat, maize or soybean. These tubers due to their large capacities to store carbohydrates are inherently strong photosynthate “sinks” implying that tuber crops should be better adapted to respond to the stimulatory effect of increasing atmospheric [CO2]. It follows that, as global atmospheric [CO2] continues to rise, so will the yield of tuber crops. People within the poorest populations depend disproportionately on cassava and other tropical tubers for food and as a cash crop. Thus, in the future, enhanced productivity of tuber crops should work to benefit those who need it most. ARS scientists in Urbana, IL discovered that Cassava fresh yields increased more than 100% when grown under field conditions in which the carbon dioxide concentration had been increased to the level that will be present in atmosphere in the middle of this century. The impact of this research is that, as the most important food crop for many undernourished populations, stimulation of cassava yields in the future elevated carbon dioxide world illustrates that at least this single element of global change will have a larger than expected positive impact on this crop and therefore on food security in the world’s most food insecure regions.
Ort, D.R., Zhu, X., Melis, A. 2011. Optimizing antenna size to maximize photosynthetic efficiency. Plant Physiology. 155:79-85.
Ainsworth, E.A., Bush, D.R. 2011. Carbohydrate export from the leaf - a highly regulated process and target to enhance photosynthesis and productivity. Plant Physiology. 155(1):64-69.
Sun, J., Zhang, J., Larue, C.T., Huber, S.C. 2011. Decrease in leaf sucrose synthesis leads to increased leaf starch turnover and decreased RuBP-limited photosynthesis but not Rubisco-limited photosynthesis in Arabidopsis null mutants of SPSA1. Plant Cell and Environment. 34(4)592-604.
Ainsworth, E.A., Ort, D.R. 2010. How do we improve crop production in a warming world? Plant Physiology. 154:526-530.
Wu, X., Oh, M., Schwarz, E., Larue, C., Sivaguru, M., Imai, B.S., Yau, P.M., Ort, D.R., Huber, S.C. 2011. Lysine acetylation is a widespread protein modification for diverse proteins in Arabidopsis. Plant Physiology. 155:1769-1778.
Drewry, D.T., Kumar, P., Long, S., Bernacchi, C.J., Liang, X., Sivapalan, M. 2010. Ecohydrological responses of dense canopies to environmental variability Part 2: Role of acclimation under elevated CO2. Journal of Geophysical Research-Biogeosciences. doi:10.1029/2010JG001341.
Drewry, D.T., Kumar, P., Long, S., Bernacchi, C.J., Liang, X., Sivapalan, M. 2010. Ecohydrological responses of dense canopies to environmental variability Part 1: Interplay between vertical structure and photosynthetic pathway. Journal of Geophysical Research-Biogeosciences. doi:10.1029/2010JG001340.
Oh, M., Wang, X., Wu, X., Zhao, Y., Clouse, S.D., Huber, S.C. 2010. Phosphorylation of Tyr-610 in the receptor kinase BAK1 plays a role in Brassinosteroid signaling and basal defense gene expression. Proceedings of the National Academy of Sciences. 107(4):17827-17832.
Gillespie, K.M., Rogers, A., Ainsworth, E.A. 2011. Growth at elevated ozone or elevated carbon dioxide concentration alters antioxidant capacity and response to acute oxidative stress in soybean (Glycine max). Journal of Experimental Botany. 62(8):2667-2678.
Huber, S.C., Kaiser, W.M., Jain, V. 2011. Post-translational regulation of nitrate reductase. In: Jain, Vanita, Kumar, P. Ananda, editors. Nitrogen Use Efficiency in Plants. New Delhi, India: New India Publishing Agency. p. 21-44.
Goren, S., Huber, S.C., Granot, D. 2011. Comparison of a novel tomato sucrose synthase, SISUS4, with previously described SISUS isoforms reveals distinct sequence features and differential expression patterns in association with stem maturation. Planta. 233:1011-1023.
Oh, M., Wu, X., Clouse, S.D., Huber, S.C. 2011. Functional importance of EAK1 tyrosine phosphorylation in vivo. Plant Signaling and Behavior. 6:400-405.
Feng, Z., Pang, J., Kobayashi, K., Zhu, J., Ort, D.R. 2010. Differential responses in two varieties of winter wheat to elevated ozone concentration under fully open-air field conditions. Global Change Biology. DOI: 10.111/j.1365-2486.2010.02184.x
Hatfield, J.L., Boote, K.J., Kimball, B.A., Ziska, L.H., Izaurralde, R.C., Ort, D.R., Thomson, A.M., Wolfe, D. 2011. Climate impacts on agriculture: Implications for crop production. Agronomy Journal. 103(2):351-370.
Bernacchi, C.J., Leakey, A., Kimball, B.A., Ort, D.R. 2011. Growth of soybean at midcentury tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion. Environmental Pollution. 159:1464-1472.