By Will Ferguson, College of Arts & Sciences

PULLMAN, Wash. – More than three billion people worldwide depend on rice for survival, and the number is expected to climb as the developing world grows. In Asia every hectare devoted to rice produces food for 27 people. By 2050, each hectare will need to support at least 43 people.

To address this challenge, Washington State University plant biologists Asaph Cousins and Gerry Edwards are working with an international consortium of researchers to supercharge photosynthesis in rice by introducing more efficient traits found in wild strains and other crops.

The School of Biological Sciences researchers recently received an award from the University of Oxford to start the third phase of the Bill & Melinda Gates foundation sponsored project – an important step toward boosting rice yields and meeting the growing food needs of the developing world.

“This is a novel effort that has important implications for being able to grow rice in very arid environments where there is not a lot of water,” Cousins said. “The research may take us another 15 years to complete, but when you consider the warming climate and a growing population, the payoff is potentially very large.”

Rice 2.0

Plants use photosynthesis to convert sunlight and water into useable energy, but some are better at it than others. Rice uses the C3 photosynthetic pathway, which is much less efficient in hot, dry environments than the C4 pathway used by plants like maize and sorghum.

“Switching” rice to use C4 photosynthesis would theoretically increase productivity by up to 50 percent. Introduction of C4 traits into rice is predicted to improve nitrogen-use efficiency, double water-use efficiency and increase tolerance to high temperatures.

Part of the WSU research involves studying how a plant’s physical characteristics and biochemistry influence its ability to use solar energy, take up carbon dioxide from the atmosphere and retain water. The researchers’ role is to identify and characterize the myriad of physiological and biochemical traits in different lines of rice that influence photosynthesis.

“There are many cases in the past where the C4 pathway has evolved in other plants,” Cousins said. “At this stage in our work, we are seeing whether or not there is enough genetic flexibility in rice to invoke the C4 syndrome.”

The creation of C4 rice hinges on either identifying C4-like traits among wild relatives and breeding them together or moving the required genes from C4 plants, like corn and sorghum, into rice.

While the research will take many years to complete, it is definitely worth the effort, Cousins said.

By 2050 there will be about 30 percent more people on the planet, so farmers will need to produce 70 percent more than they currently do. Boosting rice productivity is crucial to achieving this goal – particularly in areas such as south Asia and sub-Saharan Africa where 80 percent of the food supply is provided by smallholder farmers.

 

Contacts:
Asaph Cousins, WSU School of Biological Sciences, 509-335-8243, acousins@wsu.edu
Gerald Edwards, WSU School of Biological Sciences, 509-335-2539, edwardsg@wsu.edu
Will Ferguson, WSU College of Arts and Sciences, 509-335-3927, will.ferguson@wsu.edu