Scientists Have Genetically Modified Trees to Stop Them Releasing a Gas Linked to Climate Change and Poor Air Quality

Scientists have genetically modified trees so they do not release a gas that is thought to contribute to climate change and poor air quality.

An international team of researchers used a technique to silence gene expression in poplar trees so they would stop giving off isoprene—a common organic compound that reacts with other substances in the atmosphere to form types of aerosol and ozone. Findings are published in the journal PNAS.
Poplar trees are a source of biofuel, and are also used to make products like paper, and plywood. The plants take up around 36,300 square miles of land across the world, which is more than double that of 15 years ago.

Plants like poplar trees create isoprene when they are under stress, for instance following a spike in temperatures or during a drought. After it is released into the atmosphere and meets pollutants emitted by fossil fuel-burning vehicles, potentially harmful ground level ozone is created. Isoprene also increases the lifetime of the greenhouse gas methane, as well as the production of aerosols in the atmosphere, "all of which affect the global energy budget and/or lead to the degradation of air quality" as well as the climate, the authors wrote.

The team planted them in Oregon and Arizona, and watched their progress over a period of around three to four years.

By tweaking the trees' genetic code, the scientists were able to suppress the creation of isoprene without affecting how much biofuel they produced. The modified poplars also seemed to fair as well as their untouched counterparts, who could still use isoprene to combat stress.

Lead author Russell Monson, professor of ecology and evolutionary biology at the University of Arizona, explained how: "The suppression of isoprene production in the leaves has triggered alternative signaling pathways that appear to compensate for the loss of stress tolerance due to isoprene," he said in a statement.
"The trees exhibited a clever response that allowed them to work around the loss of isoprene and arrive at the same outcome, effectively tolerating high temperature and drought stress."

Study co-author Steven Strauss, distinguished professor of forest biotechnology at Oregon State University, added: "That's what we wanted to examine—can you turn down isoprene production, and does it matter to biomass productivity and general plant health? It looks like it doesn't impair either significantly.

"Our findings suggest that isoprene emissions can be diminished without affecting biomass production in temperate forest plantations."

The team believe biofuel levels were not affected because it is created before the hottest and driest part of the growing season.

Monson said: "This means that, for this species, the natural seasonal cycle of growth works in favor of high biomass production when the beneficial effects of isoprene are needed least.

"The fact that cultivars of poplar can be produced in a way that ameliorates atmospheric impacts without significantly reducing biomass production gives us a lot of optimism," he said. "We're striving toward greater environmental sustainability while developing plantation‐scale biomass sources that can serve as fossil fuel alternatives."

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A stock image shows a row of poplar trees. Getty