An international research team has found they can increase corn productivity by targeting the enzyme in charge of capturing CO2 from the atmosphere. Maize, or corn, is a staple food for billions of people around the world, with more maize grown annually than rice or wheat. In Australia, maize has the widest geographical spread of all the field crops, but it remains a small crop compared to wheat or rice. Researchers were able to produce a maize with improved photosynthesis which means more growth. Lead researcher Dr Robert Sharwood, of the Australian National University, said this could potentially increase tolerance to extreme growth conditions “There is an urgent need to deliver new higher-yielding and highly adapted crop species, before crops are affected by the expected climate change conditions,” Dr Sharwood said. “These conditions will increase the threats against global food security, and the only way to prepare for them is through international research collaborations.” 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 per cent 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. “Maize has one of the most efficient Rubiscos and they need less nitrogen to work,” said co-researcher David Stern, from the Boyce Thompson Institute, an affiliate of Cornell University. “So, our main question was, if we increase Rubisco content in maize, what would it do for the plant? We found that by boosting Rubisco inside the maize cells, we get an increase in crop productivity. “This is a very exciting finding, because it shows that there is room for improvement even in the more productive C4 crop species.” The study improved CO2 assimilation and crop biomass by 15 per cent. Dr Sharwood said the next step was to do field trials to see how the maize behaved in real field conditions. So far they have been tested in glasshouse and cabinet conditions.