Design a more productive corn that can cope with future climates

Corn, or maize, is a staple food for billions of people around the world. He grows more maize each year than rice or wheat. In Australia, maize has the largest geographical spread among all major crops, but it remains a small crop relative to wheat or rice. However, it is a culture that has all the key elements to become the food and energy culture of the future.

"We have developed a transgenic corn designed to produce more Rubisco, the main enzyme involved in photosynthesis, resulting in a plant with improved photosynthesis and therefore growth, which could potentially increase tolerance to extreme growth conditions." Center of Excellence ARC for Translational Photosynthesis, led by the Australian National University (ANU).

"There is an urgent need to provide new, high – yielding, highly – adapted crop species before crops are expected to be impacted by climate change, which will increase threats to global food security and the only way to sustain global warming. prepare international research collaborations. "

All the plants on the planet use photosynthesis to capture carbon dioxide from the atmosphere, but not all plants do it the same way. Plants such as wheat and rice use the earlier less effective C3 photosynthetic pathway, while other plants such as maize and sorghum use the most efficient C4 pathway.

C4 plants include some of the world's largest food, feed and biofuel crops, accounting for 20 to 25 percent of the planet's land productivity. These plants are specially adapted to thrive in hot, dry environments, such as those that should be more present in the coming decades.

At the center of this process is Rubisco, the main photosynthesis enzyme, responsible for converting CO2 into organic compounds. In C4 plants, Rubisco works much faster and is more tolerant of heat and drought due to better water use efficiency.

"Corn has one of the most effective rubiscos and requires less nitrogen to work in. So our main question was, if we increased the Rubisco content in corn, what would it do for the plant? We found that by strengthening Rubisco in corn cells, we get an increase in crop productivity, "said co-investigator David Stern, of the Boyce Thompson Institute, a subsidiary of Cornell University. .

This is a very interesting discovery because it shows that improvements are possible even in the most productive C4 crop species.

"In our study, we have improved CO2 assimilation and crop biomass by 15%, but we now know that we can also increase the pool of active Rubisco and that these numbers will increase even more," the report said. Dr. Sharwood.

"Our next step is to do field trials to see how our corn behaves in real-world conditions, we tested them under greenhouse and cabinet conditions, but now we need to move on to the next phase," said Dr. Sharwood.

This research is published in Natural plants.

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More information:
Coralie E. Salesse-Smith et al. Overexpression of Rubisco subunits with RAF1 increases Rubisco content in corn, Natural plants (2018). DOI: 10.1038 / s41477-018-0252-4