PI – Andrew Leakey ((UIUC)
Co-PI – Don Ort (USDA)

Funding Source: USDA $349K to Illinois USDA 2010–65114–20343

By 2050, the Midwest US will be at greater risk of droughts, and [CO2] will rise to ≥550 ppm. It takes weeks of dry weather for the large rooting zone of field crops to dry out. In this time, plants produce signals in the roots that modify shoot function and they also can alter their metabolism to regulate the osmotic status of tissues. We will test how growth at elevated [CO2] will alter the contribution of these two processes to drought tolerance in soybean growing in the U.S. Corn Belt. We will use the SOYbean Free-Air Concentration Enrichment (SOYFACE) facility to grow soybean under the best possible simulation of future drought and elevated [CO2] conditions, in the primary soybean growing area of the US. The [CO2] treatment will be imposed with 4 control (~380 ppm) and 4 elevated [CO2] (~550 ppm) plots. In a split-plot design, there will be 8 x 4 m control and drought subplots within each FACE plot. In each drought subplot, rain will be intercepted by a retractable awning and drained via a gutter. We will identify the changes in gene expression and biochemistry that underlie the physiological and agronomic responses of soybean to the interacting influences of drought and elevated [CO2]. This will generate essential knowledge needed to guide crop improvement that will adapt soybean production to future conditions, and addresses two of the three Program Priorities: “water stress” and “global change stress including increased CO2”.