Rubisco study could lead to bumper crops

Research led by scientists at the Australian National University could lead to major improvements in crop production. The researchers have gone back to the future to discover a breakthrough method that will help them to study and ramp up photosynthesis… And it’s based on revisiting an original, billion-year-old strategy in plants.

The research looks specifically at Rubisco activity. This is a crucial part of the photosynthesis process, explains study co-author Professor Spencer Whitney.

“Rubisco is an enzyme involved in the first step of carbon fixation,” he says. “It starts the conversion of carbon dioxide into plant sugars. But compared to other enzymes, Rubisco is considered a slow, inefficient catalyst.”

Many enzymes can process hundreds to thousands of molecules per second. However, Rubisco can only get through two to five cycles per second, the professor explains.

“For this reason, it’s long been recognised as a good target for improving photosynthesis,” he says. “It’s a puzzle scientists have been looking at for decades.”

Turning back the clock

In plants, Rubisco is made up of 16 proteins – eight large and eight small sub-units. Until now, scientists have only been able to tinker with one sub-unit at a time.

“We’ve now turned back the clock a billion years to rectify this limitation,” Professor Whitney says. “By reapplying the genome design of the bacterial ancestors of chloroplasts, we can now play around with all the components of Rubisco simultaneously. This is crucial. To ramp up its activity you have to make changes to all the components.”

These findings could mean big gains for canola and potato crops in particular.

“We know we can already tinker with Rubisco activity in these crops, so it’s a great place to start,” Professor Whitney says. “This is just the first step. This technology could eventually deliver something much bigger in the not so distant future.”