Shedding light on the energy-efficiency of photosynthesis

July 3, 2018, UC Davis
Credit: CC0 Public Domain

Photosynthesis is one of the most crucial life processes on earth. It's how plants get their food, using energy from sunlight to convert water and carbon dioxide from the air into sugars. It's long been thought that more than 30 percent of the energy produced during photosynthesis is wasted in a process called photorespiration.

A new study led by researchers at the University of California, Davis, suggests that photorespiration wastes little and instead enhances nitrate assimilation, the that converts nitrate absorbed from the soil into protein.

"Understanding the regulation of these processes is critical for sustaining food quality under climate change," said lead author Arnold Bloom in the Department of Plant Sciences at the UC Davis College of Agricultural and Environmental Sciences. The study was published July 2 in the journal Nature Plants.

During photorespiration, the most prevalent protein on the planet, called Rubisco, combines sugars with oxygen in the atmosphere instead of . This was thought to waste energy and decrease sugar synthesis. Rubisco, thus, seemed to act like the molecular equivalent of a good friend with a bad habit. Researchers speculate that photorespiration persists because most have reached an evolutionary dead-end.

Bloom proposes that something else is going on that shows plants aren't so stupid. Rubisco also associates with metals, either manganese or magnesium. When Rubisco associates with manganese, photorespiration proceeds along an alternative biochemical pathway, generates energy for nitrate assimilation, and promotes protein synthesis. Nearly every recent test tube study of Rubisco biochemistry, however, has been conducted in the presence of magnesium and absence of manganese, allowing for only the less energy efficient pathway for photorespiration.

"There's a lot we can learn from observing what plants are doing that can give us clear messages of how we should proceed to develop crops that are more successful under the conditions we anticipate in the next few decades," said Bloom.

Explore further: Helping plants remove natural toxins could boost crop yields by 47 percent

More information: Arnold J. Bloom et al, Manganese binding to Rubisco could drive a photorespiratory pathway that increases the energy efficiency of photosynthesis, Nature Plants (2018). DOI: 10.1038/s41477-018-0191-0

Related Stories

Rising CO2 levels threaten crops and food quality

May 13, 2010

Rising levels of atmospheric carbon dioxide interfere with plants’ ability to convert nitrate into protein and could threaten food quality, according to a new study by researchers at the University of California, Davis. ...

The future of crop engineering 

December 8, 2017

Photosynthesis is the process underlying all plant growth. Scientists aim to boost photosynthesis to meet the increasing global demand for food by engineering its key enzyme Rubisco. Now, researchers at the Max Planck Institute ...

Shoe strings and egg openers

November 8, 2011

Photosynthesis is one of the most important biological processes. However, it is less efficient in plants than it could be. Red algae, in contrast, use a slightly different mechanism and are thus more productive. Scientists ...

Recommended for you

Houseplants could one day monitor home health

July 20, 2018

In a perspective published in the July 20 issue of Science, Neal Stewart and his University of Tennessee coauthors explore the future of houseplants as aesthetically pleasing and functional sirens of home health.

Putting bacteria to work

July 20, 2018

The idea of bacteria as diverse, complex perceptive entities that can hunt prey in packs, remember past experiences and interact with the moods and perceptions of their human hosts sounds like the plot of some low-budget ...

LC10 – the neuron that tracks fruit flies

July 20, 2018

Many animals rely on vision to detect, locate, and track moving objects. Male Drosophila fruit flies primarily use visual cues to stay close to a female and to direct their courtship song towards her. Scientists from the ...

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

betterexists
not rated yet Jul 03, 2018
That's why it is ESSENTIAL to start making Amoeba (Protozoan), Hydra, Earthworm, Frog etc., to be capable of surviving on Photosynthesis alone one after the other. If only we too can do it, say a century from now....That will be a GREAT Achievement ! The sooner we start to focus on the task, the better. EATING FOOD is STUPIDITY EXTRAORDINAIRE !
betterexists
not rated yet Jul 03, 2018
The sooner we start to focus on the task, the better. EATING FOOD is STUPIDITY EXTRAORDINAIRE !
Instead of leaving it to nature, we should try to dig into it ! There is no mystery in nature. Several worms, insects, butterflies, fish, birds, primates....Everything is DNA Based. After 100 years, none of us...at least almost all of us living now will exist.
dudester
not rated yet Jul 04, 2018
I'm guessing you don't put much stock in Murphy's Law?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.