John Cushman, foundation professor with the Department of Biochemistry & Molecular Biology, has been awarded two patents for his research on improving drought tolerance and water-use efficiency of plants. This work, which showed a significant breakthrough in research for crop improvement, will help to preserve agricultural productivity during periods of intense heat or extended drought.
U.S. Patent 11,053,512 was awarded last year to Cushman and former postdoctoral research scholar in the department, Sung Don Lim, who is currently an assistant professor at Sangji University, South Korea. The patent addresses the process of increasing tissue succulence in plants. Improving on his team’s past work using Arabidopsis, or mouse-eared cress, Cushman is using biotechnology to increase the tissue succulence of the plant by making the leaves about 40% thicker, allowing them to store more water. Plants with high tissue succulence, such as the saguaro cactus, are more adapted to surviving in arid climates.
Working with postdoctoral students in the College of Agriculture, Biotechnology & Natural Resources to conduct this work, the team also included graduate research assistant Jesse Mayer, who conducted work on plant tissue succulence using Arabidopsis.
U.S. Patent 10,858,404 was awarded in December 2020 to Cushman, Lim and Cushman’s departmental colleague Assistant Professor Won Cheol Yim, and outlined a synthetic biology approach that allows the transfer of the drought-tolerant trait called crassulacean acid metabolism (CAM) from desert-adapted plants to major crops, such as soybean, one of the leading crops in the United States.
The team is using CAM, an alternative form of photosynthesis used by agave and cactus, to limit water loss by absorbing carbon dioxide through open pores, or stomata, in their leaves and storing it as malic acid at night, because water vapor is less likely to escape the leaves in the cooler, more humid night conditions. During the day, the stomata stay fully or partially closed while the plant uses the stored malic acid and sunlight to convert carbon dioxide into sugars and starch.
“We wanted to file these patents because we thought this could be important and applicable to a number of crop species,” Cushman said. “We chose to test this process on soybean because it’s a vital crop, and it suffers a lot of loss due to drought stress. We’re hoping we can eventually continue this work with other vital crops as well.”
Cushman and his team are testing both processes on soybean to improve productivity, water-use efficiency, and drought and salinity tolerance under hotter and drier environments. Once testing on soybean is complete, the engineering could potentially be used to target other vital crops, such as corn.
