Designing a more productive corn able to cope with future climates

An international research team has found they can increase corn productivity by targeting the enzyme in charge of capturing CO2 from the atmosphere. This research is published in Nature Plants.

“We developed a transgenic maize designed to produce more Rubisco, the main enzyme involved in photosynthesis, and the result is a plant with improved photosynthesis and hence, growth. This could potentially increase tolerance to extreme growth conditions,” said lead researcher Dr. Robert Sharwood from the ARC Centre of Excellence for Translational Photosynthesis, led by The Australian National University (ANU).

Every plant on the planet uses photosynthesis to capture carbon dioxide from the atmosphere, but not all plants do it in the same way. Plants like wheat and rice use the ancient, less efficient C3 photosynthetic path, while other plants such as maize and sorghum use the more efficient C4 path.
C4 plants include some of the world’s most important food, feed and biofuel crops, accounting for 20-25 percent of the planet’s terrestrial productivity. These plants are specially adapted to thrive in hot and dry environments, like the ones that are expected to be more prevalent in future decades.
Central to this process is Rubisco, the main enzyme of photosynthesis, which is in charge of converting CO2 into organic compounds. In C4 plants, Rubisco works much faster and they are more tolerant to heat and drought through better water use efficiency.

Researchers overexpress the Rubisco large (LS) and small (SS) subunits with the Rubisco assembly chaperone RUBISCO ASSEMBLY FACTOR 1 (RAF1). While overexpression of LS and/or SS had no discernable impact on Rubisco content, addition of RAF1 overexpression resulted in a >30% increase in Rubisco content. CO2 assimilation and crop biomass increase by 15%.

“Our next step is to do field trials to see how our maize behaves in real field conditions.,” said Dr. Sharwood.

Coralie E. Salesse-Smith et al, Overexpression of Rubisco subunits with RAF1 increases Rubisco content in maize, Nature Plants (2018). DOI: 10.1038/s41477-018-0252-4

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