How to stop plants from hurting themselves

Researchers have discovered a gene that might limit plant damage during drought or other times of stress

Most plants, including major crops, are highly inefficient at converting photosynthesis into energy.

“We expect the solar cells we put on our rooftops to be at least 15 or 20 percent efficient,” said Robert Blankenship, a biologist at Washington University in St. Louis, Missouri, on, a science and technology website.

“A plant is at best one percent efficient…. If we can double or triple the efficiency of photosynthesis — and I think that’s feasible — the impact on agricultural productivity could be huge.”

Many biologists are working on that problem, but a group of researchers at Oxford University have taken a different approach.

Instead of trying to improve photosynthesis, they may have found a way to limit the damage that sunlight causes to crops when growing conditions are harsh.

During times of stress, such as drought, the photosynthetic process can generate substances known as reactive oxygen species, which are toxic to plants.

The Oxford scientists discovered a gene that slows the photosynthetic process during times of environmental stress.

Called SP1, the gene reduces the production of toxic compounds when the plant is suffering from drought, lack of nutrients or high salinity.

Plants that over-expressed the SP1 gene in lab tests produced fewer reactive oxygen species and didn’t suffer serious or fatal damage.

The Oxford scientists said all plants have the SP1 gene, so it “should be possible to create crops that can grow more easily in harsh environments” by modifying plants to “over-express” the SP1 gene.

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Jitao Zou, a National Research Council plant biologist and adjunct professor at the University of Saskatchewan, said the SP1 gene could be a novel discovery.

“The finding is new to me, in terms of the specific function (of the gene),” he said.

“You see reports like this type quite often, (but) this one was published in a high impact journal, Current Biology…. I think it’s a major paper.”

Zou said the SP1 gene is comparable to a rooftop TV antenna from the 1970s, which receives an abundance of signals if it is large and open.

The SP1 gene closes up the antennae and makes it smaller, so the plant processes less sunlight.

“(So) it doesn’t receive that much light and therefore it reduces reactive oxygen species,” Zou said.

Zou said the Oxford finding is unique because most biologists want to enhance photosynthesis.

“There has been a surge in interest in the photosynthetic process…. The majority of the scientists in this area are interested in how to improve photosynthesis efficiency and (crop) yield.”

Most plant scientists used to assume photosynthesis was inflexible and that it wasn’t possible to enhance the process.

“In recent years, there have been some developments showing there are variations, meaning different plant species have variable capacity of photosynthesis,” Zou said.

“That would indicate … you could improve (it).”

Increasing photosynthesis efficiency from one to two percent would be a scientific accomplishment, but farmers don’t need crops that are larger or taller. They want crops that produce more yield.

Scientists have used plant breeding to improve the harvest index of crops, which is the ratio of harvested product to the total plant weight of a crop.

Zou said improving photosynthesis would amplify crop development, but the biological enhancements would also need to augment seed production.


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