Scientists in China and Japan have developed a method to increase paddy field-grown rice yield by over 30 percent while sequestering more CO2 and using less fertilizer than traditional varieties.

Researchers at Nagoya University in Japan and Nanjing Agricultural University in China achieved this functionality by increasing the expression of the plasma membrane proton pump gene OSA1 in the rice plant, which was previously found to influence stomatal opening.

CO2 intake in plants occurs exclusively through the stomata, which are holes on the leaves surface.

By increasing nutrient uptake and stomatal opening, the researchers were able to increase the rate of photosynthesis thereby speeding up growth and yield with less resources. 

This new genetics-based approach detailed in Nature could improve crop efficiency for more types of plants to increase the food supply while mitigating the overproduction of CO2. 

New functionality 
The group of scientists found the proton pump overexpressed rice, when compared to a wild strain, took up over 20 percent more mineral nutrients through its roots and opened its stomata over 25 percent wider when exposed to light. 

On further analysis, they found that its carbon dioxide storage capacity (the indicator of photosynthesis activity) increased by over 25 percent. Its dry weight (biomass) increased by 18 to 33 percent in hydroponic laboratory growth.

Testing rice in the field
With this determined, the researchers set out to find if the results could be replicated under realistic growing conditions. 

They conducted yield measurement exercises at four separate rice farms over the course of two years, finding that the rice with the overexpressed OSA1 gene had a yield over 30 percent higher than that of the wild strain. 

They also discovered that even if the level of nitrogen fertilizer was reduced by half, it still produced a greater yield than the wild strain did with normal levels of nitrogen.

Capturing more CO2
As they take in mineral nutrients such as nitrogen, phosphorus and potassium through their roots, plants simultaneously absorb carbon dioxide through the stomata on their leaves and grow through photosynthesis. 

Photosynthesis enables, not only the farming of plants for food, but the exchange of carbon dioxide and management of the earth’s environment. 

While these early-stage models have been created through genetic modification (GM), the researchers anticipate that future generations will use genome editing or chemical engineering instead.