|Allen, Leon - Hartwell|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2002
Publication Date: 7/31/2003
Citation: Thomas, J.M., Boote, K.J., Allen, Jr., L.H., Gallo-Meagher, M., Davis, J.M. 2003 Crops Science. Elevated temperature and carbon dioxide effects on soybean seed composition and transcript abundance.V.43,P. 1540-1547 Interpretive Summary: Rising carbon dioxide (CO2) and Global Warming might change the food quality of our seed crops. To study this question, USDA, ARS and University of Florida Scientists at Gainesville, FL grew soybean under day/night temperature cycles of 82/64 up to 111/93 degrees Fahrenheit, and at two CO2 concentrations, 350 ppm (near ambient) and 700 ppm (doubled). They analyzed the impacts of CO2 and temperature on yield and food value of mature soybean seeds, and determined if there were changes in the function of certain genes during seed growth in the pods. Temperature effects on both developing and mature seeds were pronounced. CO2 increased final yield but did not change seed quality. However, yields decreased sharply with increasing temperature. Total oil, carbohydrate, nitrogen (protein), and phosphorus concentrations decreased with increasing temperature. The oil component oleic acid increased but linolenic acid decreased. A gene that regulates seed development, and another that regulates carbohydrate metabolism, were severely downregulated by increasing temperature, Thus, high temperature decreases the food quality of soybean seeds. Methods were initiated to improve future research on how climate changes will affect our food derived from seed crop plants.
Technical Abstract: The effects rising carbon dioxide (CO2) and elevated temperature on composition and selected gene expressions of soybean seeds were measured. Plants were grown at maximum/minimum temperatures of 28/18, 32/22, 36/26, 40/30, and 44/34 Celsius and at 350 and 700 PPM of CO2. The temperature effect on mature seeds and transcripts in developing seed was pronounced, but there was no CO2 effect. Oil concentration was highest at 32/22 Celsius and decreased with increasing temperature. Oleic acid concentration increased but linolenic acid decreased with temperature. Concentrations of N and P increased with temperature. Total nonstructural carbohydrates decreased as temperature increased. Transcripts of two genes were decreased drastically for seeds growing at 40/30 compared to 28/18 Celsius. One was a gene that regulates seed development, similar to Auxin Down Regulated 12 (ADR12), The other gene was similar to beta-glycosidase, which enables glucose to be cleaved from various glucosidases. These results extend previous studies indicating that high temperature alters soybean seed composition, and provides molecular probes to facilitate future research on how climate change might affect soybean seed development and composition.