Drought protection for plants

As climate change threatens farmers with more frequent and longer-lasting droughts, researchers are exploring how to help. Back in 2013, Sean R. Cutler’s group at the University of California, Riverside, identified a compound that mimicked the plant hormone abscisic acid (ABA). When applied to some plants, it helped them retain water (Proc. Natl. Acad. Sci. U.S.A. 2013, DOI: 10.1073/pnas.1305919110). But that compound, quinabactin, did not work well on some key crops, including wheat and tomato. The researchers performed structural studies to dig into why that might be and found that while ABA itself can bind to its receptors at two positions, in some ABA receptors, quinabactin binds to only one position. Now, the Cutler team has combined virtual screening and structure-guided design to develop a new compound it calls opabactin, which binds at both positions (Science 2019, DOI: 10.1126/science.aaw8848). The researchers tested opabactin on tomato and wheat plants in the lab and found that the new compound exhibits more potent and long-lasting effects than existing treatments. Cutler says time will tell if opabactin will be viable to treat drought in the field, but it may be useful for studying the role of ABA in plants.