Husker research indicates improved water use efficiency in crops

Lincoln, Nebraska, August 22, 2024 – Scientists at the University of Nebraska–Lincoln have discovered a promising approach to help crops cope with drought. By modifying the genome to increase an important plant protein, the researchers enabled the plants to reduce their water use by up to 30% under drought-like conditions.

The results mark “an important step toward developing future crops with improved drought performance,” the researchers write in a new article. in the Journal of Experimental Botany.

Husker researchers bred tobacco plants under various drought conditions and found that a particular genetic modification allowed the plants to use 4 to 30 percent less water overall than normal plants. Tobacco plants are useful for research because they are generally easy to cultivate and grow quickly. Their genetic details are well known and they lend themselves well to genetic modification, facilitating follow-up research with other, more complex crops.

“Plants use up to 30% less water, but the biomass – that is, their size – ultimately does not change significantly,” says Kasia Glowacka, assistant professor of biochemistry. Her lab uses a wide range of analytical techniques to strengthen crops’ resilience to climate stress.

A particular focus is improving water use efficiency in plants, which led her lab to conduct advanced studies on non-photochemical quenching, an important biological safety valve process. Plants use this process to protect themselves from stress and damage when they receive more light energy than they can use for photosynthesis.

Non-photochemical quenching can regulate the opening of stomata, pores through which a plant takes in carbon dioxide (important for plant growth) while releasing water vapor and oxygen.

Glowacka’s lab increased the amount of PsbS, a protein involved in non-photochemical quenching. Increased amounts of this protein reduced stomatal opening by increasing non-photochemical quenching in response to light. The result was improved water use efficiency.

“It’s not that we close the stomata,” Glowacka said. “We change their behavior.”

In the new paper, she and her co-authors wrote that the lab’s findings “provide proof of concept that by overexpressing PsbS, it is possible to alter stomatal aperture under drought conditions to achieve higher water use efficiency and reduce water use at the whole plant level without significant loss of biomass.”

The plants in the project lost 11% less water per unit of carbon dioxide absorbed than normal plants, without any significant impact on plant size. Given climate stresses and limited water resources for agriculture worldwide, progress is needed in developing crops that require less water per mass of yield, the researchers wrote.

The results are “really exciting because we don’t see a drop in growth,” Glowacka said. “So that’s a good starting point. It’s proof that it works.”

The next step is to further develop genome modification to increase crop yields under water-stress conditions. The Glowacka lab is currently conducting this research.

Other Husker researchers involved in the project included Geng Bai, research assistant professor in the Department of Biosystems Engineering, and postdoctoral researchers Benjamin Turc and Seema Sahay, Jared Haupt, a Husker graduate student, and Talles de Oliveira Santos, a visiting student from the State University of Northern Rio de Janeiro, Brazil.