Scientists tweak photosynthesis to up crop yield

•  Scientists have successfully tweaked the process of photosynthesis to make it more efficient and increase plant productivity by raising the level of three proteins involved in the process. Researchers used tobacco plants for this experiment as they can be easily modified.

About Process:

• Scientists saw increases of 14 per cent to 20 per cent in the productivity of their modified tobacco plants which confirms that photosynthesis can be made more efficient to increase plant yield, a hypothesis some in the scientific community once doubted was possible.
• The team targeted a process plants use to shield themselves from excessive solar energy.
• Crop leaves exposed to full sunlight absorb more light than they can use. If they can't get rid of this extra energy, it will actually bleach the leaf.
• Plants protect themselves by making changes within the leaf that dissipate the excess energy as heat. This process is called non photochemical quenching (NPQ).
• But when a cloud crosses the sun, or a leaf goes into the shade of another, it can take up to half an hour for that NPQ (non-photochemical quenching of chlorophyll fluorescence) process to relax. In the shade, the lack of light limits photosynthesis, and NPQ is also wasting light as heat.
• Scientists have inserted a "cassette" of the three genes (taken from the model plant Arabidopsis) into tobacco. The objective was simply to boost the level of three proteins already present in tobacco.
• The researchers grew seedlings from multiple experiments, and then tested how quickly the engineered plants responded to changes in available light.
• A fluorescence imaging technique allowed the team to determine which of the transformed plants recovered more quickly upon transfer to shade. The researchers selected the three best performers and tested them in several field plots alongside plots of the unchanged tobacco.
• Two of the modified plant lines consistently showed 20 per cent higher productivity, and the third was 14 per cent higher than the unaltered tobacco plants.
• Tobacco is grown for its leaves, which were substantially increased. But in food crops, it will be whatever we eat from the plant - the fruit, the seeds or the roots - that we will need to increase.
• Crop yield gets big boost with modified genes in photosynthesis
• Tobacco leaves showing transient overexpression of genes involved in nonphotochemical quenching (NPQ), a system that protects plants from light damage. Red and yellow regions represent low NPQ activity, while blue and purple areas show high.
• Other experiments have demonstrated that increasing photosynthesis by exposing plants to high carbon dioxide results in more seeds in wheat, soy and rice.
• Now we can do this genetically, and we are actively working on repeating our work in various food crops.
• This finding offers some rare good news at a time of dire forecasts of future food shortages.

By: Vishal