Spectral analysis to predict photosynthetic capacity

The traditional method for assessing photosynthesis analyses the exchange of gases through the leaf; it provides a huge amount of information, but it takes 30 minutes to measure each leaf. Researchers at the University of Illinois have now developed a new method, which allows them to measure improvements they engineered in a plant’s photosynthesis machinery in about 10 seconds.

RIPE project

The research project is called Realising Increased Photosynthetic Efficiency (RIPE). The new method is a major advance, says Katherine Meacham-Hensold, a postdoctoral researcher at the University of Illinois and leader of the project. “It allows our team to analyse an enormous amount of genetic material to efficiently pinpoint traits that could greatly improve crop performance.”

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The traditional method for assessing photosynthesis analyses the exchange of gases through the leaf, as performed here by Katherine Meacham. This takes 30 minutes. – Photo: RIPE Project

RIPE, which is led by Illinois, is engineering crops to be more productive by improving photosynthesis, the natural process all plants use to convert sunlight into energy and yield.

Photosynthetic machinery genetically altered

“The question we set out to answer is: can we apply spectral techniques to predict photosynthetic capacity when we have genetically altered the photosynthetic machinery,” said RIPE research leader Carl Bernacchi, a scientist with the U.S. Department of Agriculture, Agricultural Research Service, who is based at Illinois’ Carl R. Woese Institute for Genomic Biology. “Before this study, we didn’t know if changing the plant’s photosynthetic pathways would change the signal that is detected by spectral measurements.”

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Predictive models

Although they can prove this method can be used to screen crops that have been engineered to improve photosynthesis, researchers have not uncovered what spectral analysis measures exactly. “Spectral analysis requires custom-built models to translate spectral data into measurements of photosynthetic capacity that must be recreated each year,” Meacham said. “Our next challenge is to figure out what we are measuring so that we can build predictive models that can be used year after year to compare results over time.”

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Increase crop yields

“While there are still hurdles ahead, spectral analysis is a game-changing technique that can be used to assess a variety of photosynthetic improvements to single out the changes that are most likely to substantially, and sustainably, increase crop yields,” said RIPE executive committee member Christine Raines, a professor of plant molecular physiology at the University of Essex, whose engineered crops were analysed with the technique. “These tools can help us speed up our efforts to develop high-yielding crops for farmers working to help feed the world.”

Also read: How much can enhancing photosynthesis improve yield?