Food securityImproving crop resilience, yields in a world of extreme weather

Farmers in the United States witnessed record-breaking extremes in temperature and drought during the last two summers, causing worldwide increases in the costs of food, feed and fiber. Indeed, many climate scientists caution that extreme weather events resulting from climate change is the new normal for farmers in North America and elsewhere, requiring novel agricultural strategies to prevent crop losses.

A UC Riverside release reports that now a research team led by Sean Cutler, a plant cell biologist at the University of California, Riverside, has found a new drought-protecting chemical that shows high potential for becoming a powerful tool for crop protection in the new world of extreme weather.

Named “quinabactin” by the researchers, the chemical mimics a naturally occurring stress hormone in plants that helps the plants cope with drought conditions.

Study results appear online this week in the Proceedings of the National Academy of Sciences.

All land plants have intricate water sensing and drought response systems that are tuned to maximize their fitness in the environments they live in. For example, plants in environments with low water grow slowly so that they do not consume more water than is available.

“But since farmers have always desired fast-growing varieties, their most valued strains did not always originate from drought-tolerant progenitors,” explained Cutler, an associate professor of plant cell biology. “As a result, we have crops today that perform very well in years of plentiful water but poorly in years with little water. This dilemma has spawned an active hunt for both new drought-tolerant crops and chemicals that farmers might use for improving crop yield under adverse conditions.”

Working on Arabidopsis, a model plant used widely in plant biology labs, Cutler and his colleagues focused their efforts on tinkering with one of the plant endogenous systems involved in drought responses.  Plant leaves are lined with tiny pores, called stomata, which dynamically open and close to control the amount of water lost to the environment by evaporation. So that the plants can acquire carbon dioxide from the atmosphere, the pores need to be open some of the time, resulting in some loss of water.

During drought the stomata close firmly to limit water loss. Behind the scenes, a small hormone called abscisic acid (ABA) orchestrates the opening and closing of the pores.  Cells throughout the plant produce increasing amounts of ABA as water levels decrease.  ABA then moves throughout the plant to signal the stressful