[cough..shades of Reagan…cough~]
University of Arizona
While providing benefits to the environment, some trees also emit gases to the atmosphere that worsen air pollution and alter climate. Field trials in Oregon and Arizona show that poplar trees, which emit trace amounts of the gas isoprene, can be genetically modified not to harm air quality while leaving their growth potential unchanged.
The findings, published today in the journal Proceedings of the National Academy of Sciences, are important because poplar plantations cover 9.4 million hectares (36,294 square miles) globally – more than double the land used 15 years ago. Poplars are fast-growing trees that are a source of biofuel and other products including paper, pallets, plywood and furniture frames.
Poplars and other trees used in plantation agroforestry, including palms and eucalyptus, produce isoprene in their leaves in response to climate stress such as high temperature and drought. The isoprene alleviates those stresses by signaling cellular processes to produce protective molecules; however, isoprene is so volatile that millions of metric tons leak into the atmosphere each year.
The emitted isoprene reacts with gases produced by tailpipe pollution to produce ozone, which is a respiratory irritant. Isoprene also causes higher levels of atmospheric aerosol production, which reduces the amount of direct sunlight reaching the earth (a cooling effect), and it causes the global warming potential of methane in the atmosphere to increase (a warming effect). The warming effect is most likely greater than the cooling effect. The net effect of emitted isoprene is to worsen respiratory health and, most likely, warm the atmosphere.
A research collaboration led by scientists at the University of Arizona, the Helmholtz Research Center in Munich, Portland State University and Oregon State University genetically modified poplars not to produce isoprene, then tested them in three- and four-year trials at plantations in Oregon and Arizona.
The researchers found that trees whose isoprene production was genetically suppressed did not suffer ill effects in terms of photosynthesis or “biomass production.” They were able to make cellulose, used in biofuel production, and grow as well as trees that were producing isoprene. The discovery came as a surprise, given the protective role of isoprene in stressful climates, especially in the case of the Arizona plantation.
“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,” said Russell Monson, a professor of ecology and evolutionary biology at the University of Arizona and lead author of the study. “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.”
“Our findings suggest that isoprene emissions can be diminished without affecting biomass production in temperate forest plantations,” said study co-author Steven Strauss, a distinguished professor of forest biotechnology at Oregon State University. “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.”
The researchers used a genetic engineering tool known as RNA interference. RNA transmits protein coding instructions from each cell’s DNA, which holds the organism’s genetic code. The genetic tools for modifying the trees, and the protein analyses that revealed changes in the use of biochemical pathways, were developed by scientists at the Institute of Biochemical Plant Pathology, Helmholtz Research Center in Munich, Germany, who collaborated on the study.
“RNA interference is like a vaccination – it triggers a natural and highly specific mechanism whereby specific targets are suppressed, be they the RNA of viruses or endogenous genes,” Strauss said. “You could also do the same thing through conventional breeding. It would be a lot less efficient and precise, and it might be a nightmare for a breeder who may need to reassess all of their germplasm and possibly exclude their most productive cultivars as a result, but it could be done. New technologies like CRISPR, short for clustered regularly interspaced short palindromic repeats, which allows for precise DNA editing at specific stretches of the genetic code, should work even better.”
In an additional discovery, the researchers found that trees were able to adjust to the loss of isoprene because most plantation growth takes place during cooler and wetter times of the year.
“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,” Monson explained.
This observation also clarified an adaptive role for isoprene in natural forests, where protection that enhances survival during mid-season climate stress is likely more important than processes that promote growth early in the season.
“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,” Monson 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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Scientists from Portland State University, the University of California, Riverside, NASA’s Goddard Space Flight Center, and the Institute for Microbiology in Greifswald, Germany, also collaborated on the study.
Funding was provided in part by the National Science Foundation (1065790 and 1754430), the U.S Department of Agriculture (2013-67009-21008), the German Ministry of Education and Research (0315412), Portland General Electric, Portland State University, Oregon State University and the Water, Environmental, and Energy Solutions program supported by the Technology and Research Initiative Fund from the state of Arizona.
The warming effect is most likely greater than the cooling effect. Very ’sciencey‘.
What I love about this is the idea of using GMO to combat climate change! It must make the Left’s heads explode!
Great, they can produce GM trees to cure the planet, but producing GM Golden rice to cure humans is a step too far.
Send me saplings.
Is there a reasonable bases for this modification in the first place? On the one hand the study acknowledges isoprene production a defense system. On the other hand the isoprene production may cool or more likely warm the planet, plus eventually increase allergy.
Does a few Mt of isoprene result in any serious global climate change? This question should be answered first.
Does the isoprene production increase allergy significantly? This question goes a bit the same way as pollen allergy. Should we eradicate all or most pollen emitting plants?
Doing GM on trees only makes sense if there are mainly great advantages and very few to no negative effect of a particular GM. In this case I fail to see any significant advantages described.
Proportion is so often or rather mostly forgotten in everything related to Climate Science. Like H2O is a seriously dangerous liquid, when the proportion of it is not taken into account.
“…grow as well as trees that were producing isoprene. The discovery came as a surprise, given the protective role of isoprene in stressful climates, especially in the case of the Arizona plantation”
What probably happened is that they weren’t stressed much in a 3-4 year trial. Remember, trees can easily live a hundred years, which shows just how short a trial this really was. But academics live by the ‘learned’ paper, or die of acute grant shortage. And anyway, research these days is all about proving something you decided first -learning something is a far distant side-effect. In those rare occasions that it happens.
Hive – Understand that hybrid cottonwoods are grown on a rather short rotation. We grew them for 6 years, so the test period would have been nearly 2/3 of a rotation, which would result in trees at least 45 feet tall and 4-5″ DBH. While I’m also concerned about potential loss of plant defense, the test period was fairly robust for this species complex and growing regime.
Trees would not emit isoprenes unless there was a genetic advantage – for the trees.
Consider vaccination. If 90% of a population is vaccinated, the remaining 10% that is not vaccinated is still protected by the reduced transmission of the vacinnated 90%.
Isoprenes could do something similar. The modified trees are being protected by the unmodified trees. As a result the researchers did not observe the modification to be harmful.
Now if they will just genetically modify climate activists to have higher IQ’s, the entire problem is solved. (OK, I am assuming that a higher IQ would allow them to understand that the climate issue is not settled nor is it catastrophic…it might be they have to lower their genetically predisposed panic attack levels as well)
As others have pointed out, there is a REASON why organisms evolve into producing certain chemicals, proteins, or whatever. If it requires energy, then there is a benefit or it would have been removed. We need to understand that reason before releasing this genetically changed organism into the wild (I don’t know about you, but my back yard is pretty wild).
Robert – Not worry. The time and expense to take a transgenic variety to fully deregulated status (which would be required for you to even think about growing it in your backyard….) is frequently 10 years+ and 10’s of millions of dollars. Not for the faint of heart, or without a big checkbook.
Oh yeah, and then there is the public relations aspect. Big Ag has more or less gotten over this hump, but it seems those involved in forestry are in need of a spine transplant. That said, we are on the cusp of full deregulation for transgenic American chestnut, resistant to chestnut blight. This will be HUGE.