Ancient bacteria give plants a boost

Scientists studying some of the oldest life on Earth have discovered that the bacteria can harness wavelengths of light that modern plants cannot. Transferring the trait between the two, they say, might boost plant yields by as much as 25%...

Cyanobacteria are primitive microbes equipped with the ability to photosynthesise - capture the energy in sunlight - to make food and oxygen. 

These organisms are also the ancestors of the chloroplasts that are found doing a similar job in the leaves of modern plants.

Where plants fall down, though, is that the chlorophyll they contain to run their photosynthetic machinery cannot harvest up to 25% of the energy in the light landing on their leaves. Instead, this so-called "far-red light" is wasted.

Some cyanobacteria, however, make a different form of chlorophyll - called chlorophyll f - that can capture and use this light, although no one knew how they did it.

Now, writing in Science, Penn State University researcher Donald Bryant and his team have successfully isolated the gene responsible, which they have called "chlorophyll f synthase".

They made the discovery by comparing strains of cyanobacteria that either were or were not capable of growing in far red light conditions and asking which genes were present and active in each case.

The team confirmed that they had hit the genetic jackpot by adding the gene to a cyanobacterium strain that formerly was unable to grow in far-red light. Equipped with the new gene, the cyanobacteria were able to use far-red light for growth.

Now the team are investigating whether the gene can be added to modern plants. If it can, it could endow crops with the ability to harvest and use light that is currently squandered. This could potentially increase crop yields by 25-30%, roughly the proportion of light energy that falls within the the far-red part of the spectrum...