A discovery published in the April 14 edition of Science magazine sheds new light on how plants can be genetically enhanced to use less water. Dr. Xuemin “Sam” Wang, a Principal Investigator at the Donald Danforth Plant Science Center and an E. Desmond Lee and Family Endowed Professor in the Department of Biology at UM St. Louis, identified a protein responsible for regulating the opening and closing of plant stomata – the pores on leaves through which carbon dioxide is taken in and water is released.

“By studying the model plant Arabidopsis, members of my lab identified a protein in the pathway that delivers a plant hormone that is responsible for opening and closing the stomata on plant leaves,” Dr. Wang explained. “We discovered that a protein, phospholipase D 1 (PLD 1), mediates the effect of the hormone abscisic acid (ABA). During drought, ABA levels in plants increase to close open stomata and inhibit the opening of closed stomata. Closure of stomata is crucial to reducing water loss and maintaining water within the plant during dry periods, thus increasing the likelihood that the plant will survive.”

Stomata are the tiny openings or pores found primarily on the undersurface of plant leaves that are used for the exchange of gases. Carbon dioxide and oxygen enters the plant through these openings where they are used in photosynthesis and respiration. Oxygen exits through these same openings. Water vapor is released into the atmosphere through stomata in a process called transpiration. It is the release of water that contributes to withering of leaves during drought conditions.

“These findings are important in two ways; they provide detailed insight into how plants regulate and retain water, and offer clues that may eventually lead to developing drought-tolerant crops. The fact that this research was conducted in St. Louis demonstrates the power of collaboration between UM-St. Louis and the Danforth Center,” Dr. Roger Beachy, President of the Danforth Center announced.
Building on this discovery, scientists may one day be able to produce plants that can regulate hydration during periods of drought. This could also lead to crops that will require less water thus conserving fresh water and reducing irrigation costs.

With more than 15,000 students, the University of Missouri-St. Louis is the third largest university in Missouri. UM-St. Louis offers 46 undergraduate degree programs, 30 master's degree programs, 13 doctoral degree programs and the state's only professional degree in optometry. UMSL was founded in 1963.

Founded in 1998, the Donald Danforth Plant Science Center is a not-for-profit research institute with a global vision to improve the human condition. Research at the Danforth Center will enhance the nutritional content of plants to improve human health, increase agricultural production to create a sustainable food supply, and build scientific capacity to generate economic growth in the St. Louis region and throughout Missouri.