by Laura Kent

Photosynthesis is an essential biological process that depends on the activity of the enzyme Rubisco which catalyses carbon fixation. Rubisco is slow, inefficient and cannot accurately distinguish between CO₂ and O₂. There are variety of different types of Rubisco in plants, algae and cyanobacteria which all have the same basic structure and function.

ANU researchers have been trying to improve the efficiency of Rubisco in crop plants by studying the different forms of Rubisco in other organisms such as cyanobacteria and algae. Associate Professor Spencer Whitney discovered a more efficient form of Rubisco in red algae that has a higher affinity for CO₂ than Rubisco in plants. This discovery led to experiments to try and transplant the red algae Rubisco into crop plants to improve photosynthesis. Although red algae Rubisco cannot be assembled in plants research is still being conducted to manipulate Rubisco on the genetic level.

Researchers use biotechnology tools and genetic engineering to improve photosynthesis by changing the structure or function of Rubisco. One method is called chloroplast transformation and involves modifying the chloroplast genome by inserting foreign genes. Using this method ANU researchers have produced new varieties of tobacco with modified Rubisco and observe how these changes impact the plants growth and development. Current research involves manipulating the genes that encode for Rubisco to allow researchers to test theories about photosynthesis and develop plant mutants that have more efficient photosynthesis. 

• Whitney group web page

This article is one of a set featuring the achievements and memorable occasions in the History of Biology at ANU.