How does improving photosynthesis improve crop yield?

Over the next two decades, crop yields need to increase dramatically to feed the growing world population. Would not it be extremely helpful to have a crystal ball to show us what are the best strategies available to increase yields?

A team of scientists has just developed just that: a dynamic model that predicts which photosynthetic manipulations of plants will increase the yields of wheat and sorghum crops.

"We have developed a reliable, biologically rigorous forecasting tool that can quantify the efficiency gains associated with manipulating photosynthesis in realistic growing environments," said Alex Wu, RCA Center for Excellence. Translational photosynthesis (CoETP) and the University of Queensland. (UQ).

Plants convert sunlight, carbon dioxide and water into food through photosynthesis and several studies have shown that this vital process can be designed to be more effective.

"Until now, it was difficult to assess the impact of these manipulations on crop yield, and this forecasting tool will help us find new ways to improve crop yields." food in the world. "

Dr. Wu, the main author of the document published this week in the newspaper Plants Nature, said that this modeling tool had the ability to link crops at the biological scale ranging from leaf biochemistry to whole crop during the growing season, incorporating photosynthesis and breeding patterns. culture.

"It is a powerful tool for evaluating and guiding photosynthetic manipulations and mitigating the effects that confuse the relationship between the efficiency of photosynthesis and crop performance," he said.

Center Assistant Professor Susanne von Caemmerer said that one of the most innovative aspects of the study was to use a multi-scale modeling approach to examine the interactions between photosynthesis and the pores of the sheet allowing the exchange of CO2 and water vapor.

"We know that it's not as simple as saying that improving photosynthesis will increase yield.The response depends on the situation," said Professor von Caemmerer, researcher at the University of Toronto. Australian National University (ANU), co-author of the study. .

"For example, we found that in crops such as sorghum, higher photosynthesis can actually reduce yield in crops where the crop is limited in water, modeling predicts that we can manage this yield loss if we can also maintain a stable rate of incoming carbon dioxide or water. " outgoing vapor, the pores of a leaf ".

Professor Graeme Hammer of UQ, co-author and chief investigator of the Center, said this study encourages the type of transdisciplinary research needed for future crop improvement.

"It connects research throughout the center, which aims primarily to increase the yield of major staple crops such as wheat, rice, sorghum and maize by improving photosynthesis."

"Now that we have developed and tested this predictive model, our next step is to work closely with CoETP collaborators to design simulation scenarios that test the effects of other bioengineering targets and trait traits. selection, "said Professor Hammer.

One of these collaborators is Professor Graham Farquhar of the ANU, co-author of the study.

"In this study, we extend the entire growing season of crops and integrate the feedback effects on the photosynthesis of resources for cultivation, such as water, which is essential for predicting the consequences on crop productivity. cultures in future Australian culture environments, "said the Center's chief. Farquhar investigator professor of the ANU Research School of Biology.

The team investigated three main photosynthesis manipulation targets, namely the increase of the activity of the main photosynthetic enzyme, Rubisco; improve the capacity of the sheets to carry electrons; and improve the flow of carbon dioxide (CO2) through the inner layers of the sheet.

"This study allows us to quantify the crop yield implications for these three targets and their combinations for wheat and sorghum crops in irrigated or arid farming environments," said Dr. Wu.

The team found that crop yield ranged from a 1% reduction to a 12% increase, depending on the combination of photosynthetic goals, crop, and environmental conditions such as water availability.