|KOEHLER, I - University Of Illinois|
|RUIZ-VERA, U - University Of Illinois|
|VANLOOCKE, A - Iowa State University|
|CLEMENTE, T - University Of Nebraska|
|LONG, S - University Of Illinois|
Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/2016
Publication Date: 12/12/2016
Citation: Koehler, I.H., Ruiz-Vera, U.M., VanLoocke, A., Thomey, M.L., Clemente, T., Long, S.P., Bernacchi, C.J., Ort, D.R. 2016. Expression of cyanobacterial FBP/SBPase in soybean prevents yield depression under future climate conditions. Journal of Experimental Botany. 68(3):715-726.
Interpretive Summary: Crop production needs to increase to meet future demands, but many factors related to pollution and climate are challenging efforts to meet these demands. Therefore, efforts are needed to improve crops to better adapt to significant changes in the environment. High temperatures already negatively impact crop production and it is very likely that this problem will increase in the future. One strategy is to modify the parts of the photosynthetic pathway that is most sensitive to temperature. This research increases the activity of an enzyme known to be limiting in high temperature and high CO2 with the ultimate goal of increasing photosynthesis and temperature. Here, we modified the photosynthetic pathway of soybean and grew the modified plants under field conditions next to the unmodified plants. Plants were grown in either control, high CO2, high temperature, or combined high CO2 and high temperature to assess the treatments where the differences between the modified and unmodified plants were greatest. The results show that our modified plants had higher photosynthesis and higher yields in the elevated CO2 and warmer treatments, suggesting that this strategy to modify photosynthesis can help maintain high yields of soybean in the future.
Technical Abstract: Predictions suggest that current crop production needs to double by 2050 to meet global food and energy demands. Based on theory and experimental studies, overexpression of the photosynthetic enzyme sedoheptulose-1,7-bisphosphatase (SBPase) is expected to enhance C3 crop photosynthesis and yields. Here we test how expression of the cyanobacterial, bifunctional fructose-1,6/sedoheptulose-1,7-bisphosphatase (FBP/SBPase) affects carbon assimilation and seed yield (SY) in a major crop (soybean, Glycine max). For three growing seasons, wild-type (WT) and FBP/SBPase-expressing (FS) plants were grown in the field under ambient (400 µmol mol-1) and elevated (600 µmol mol-1) CO2 concentrations [CO2] and under ambient and elevated temperatures (+2.7 °C during daytime, +3.4 °C at night) at the SoyFACE research site. Across treatments, FS plants had significantly higher carbon assimilation (4–14%), Vc,max (5–8%), and Jmax (4–8%). Under ambient [CO2], elevated temperature led to significant reductions of SY of both genotypes by 19–31%. However, under elevated [CO2] and elevated temperature, FS plants maintained SY levels, while the WT showed significant reductions between 11% and 22% compared with plants under elevated [CO2] alone. These results show that the manipulation of the photosynthetic carbon reduction cycle can mitigate the effects of future high CO2 and high temperature environments on soybean yield.