Turbocharged Plants - 1998

These plants are busy photosynthesising. Harnessing energy from the sun by pulling carbon dioxide from the atmosphere and building it into living organisms... but they're not very good at it. Blue green algae, however, are. In fact with the right conditions, they grow so well that they become a menace, choking our inland waterways. If scientists could discover how this nuisance slime grows so fast, it could help them develop more efficient crop plants. Photosynthesis in most land plants today is surprisingly slow and clumsy compared to other biological reactions. This is because the enzyme called Rubisco, which helps plants convert carbon dioxide into sugars, has difficulty in distinguishing between the gas it needs, carbon dioxide, and another far more abundant gas, oxygen. It means a large proportion of the solar energy harvested by plants is wasted. And in hot dry countries like Australia the efficiency is even worse. Blue green algae, on the other hand, are extremely efficient and are in fact responsible for around a third of total global photosynthetic activity. Although their Rubisco enzyme is less efficient than land plants, they have evolved a highly effective carbon dioxide concentrating mechanism. Essentially it works like the turbo charger in a motor vehicle, increasing the carbon dioxide concentration around Rubisco. Dr Dean Price - "If we can incorporate the genes from cyanobacteria "into crop plants such as wheat and rice "thereby increasing photosynthetic efficiency, "then the benefits on a world wide scale would be immense." Scientists still don't have all the genes needed for this process, but recently a Japanese group posted the entire DNA sequence of one species of blue green algae on the internet, assisting the scientists looking for the right genes. Scientists believe that once this genetic information from the blue green algae is isolated, they will be able to develop crops that use less water and less nitrogenous fertilisers, helping grow more abundant crops, especially in arid countries like Australia.