Genetically modified poplars do not release air polluting chemicals
Genetically modified poplars that do not release air polluting chemicals that help in the production of ozone can be the key to saving the planet, a study suggested.
Poplars are a fast-growing source of renewable wood fuel – and are often seen as a greener alternative to fossil fuels.
However, these trees also emit high levels of the chemical isoprene that forms toxic ozone when mixed with other air pollutants in sunlight.
The genetically processed trees grow as well as their natural counterparts, US researchers said.
The fear that genetically modified trees can damage nature, however, means that arrangements whereby such plants are planted face enormous opposition.
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Genetically modified poplars that do not release air polluting chemicals that help in the production of ozone can be the key to saving the planet, a study suggested
“Our findings suggest that isoprene emissions can be reduced without affecting biomass production in temperate forest plantations,” said paper author and forest biotechnologist Steve Strauss of Oregon State University.
“That is what we wanted to investigate – can you reduce the production of isoprene, and is it important for the productivity of biomass and general plant health?”
‘It looks like it is not going backwards significantly. In Arizona, where it’s super hot, if isoprene mattered for productivity, it would appear in a striking way, but it didn’t. “
“Plants are smart – they compensate and do something else if needed.”
In three-year trials on plantations in Oregon and Arizona, the researchers demonstrated that trees can be genetically modified to reduce negative effects on air quality, while their growth potential remains virtually unchanged.
Poplar plantations cover 9.4 million hectares worldwide – more than double the land used 15 years ago – with paper, pallets, plywood and furniture frames, all made from the wood they produce.
Poplars and other trees, including oak, eucalyptus and conifers, produce isoprene in their leaves in response to high temperatures.
However, increases in isoprene – the most important component of natural rubber – are damaging regional air quality.
This also causes imbalances in the global energy budget by leading to higher levels of atmospheric aerosol production and the greenhouse gases ozone and methane.
Poplars are a fast-growing source of renewable wood fuel – and are often seen as a greener alternative to fossil fuels
The team of genetically modified poplars not to produce isoprene. Trees whose production was suppressed were not adversely affected.
Their photosynthesis or “biomass production” was the same as unaltered varieties – and they were able to make fuel and also grow.
Without the ability to produce isoprene, the modified poplars seem to make “compensatory protective compounds,” Professor Strauss explained.
Most trees also grow during cooler periods of the year, so heat stress – which triggers the production of isoprene – is likely to have little effect on photosynthesis.
The researchers used a genetic engineering tool known as RNA interference to disrupt protein coding instructions from the DNA of each cell.
“RNA interference is like a vaccination – it causes a natural and very specific mechanism that suppresses specific targets, whether it is RNA from viruses or endogenous genes,” Professor Strauss explained.
“You can also do this with DNA-level CRISPR (a tool for editing genes) – and it usually works even better.”
CRISPR – abbreviation for ‘Clustered Regularly Interspaced Short Palindromic Repeats’ – focuses on specific pieces of genetic code for DNA processing at exact locations.
However, these trees also emit high levels of the chemical isoprene that forms toxic ozone when mixed with other air pollutants in sunlight
“You could also do the same through conventional breeding,” said Professor Strauss.
“It would be a lot less efficient and accurate and it could be a nightmare for breeders who may have to reassess all their germplasm and possibly exclude their most productive cultivars as a result, but it could be.”
The researcher’s work paves the way for future isoprene research – also in various growing environgene.
“The fact that poplar cultivars can be produced in a way that improves atmospheric effects without significantly reducing biomass production gives us a lot of optimism,” said paper author and Arizona University ecologist Russell Monson.
“We strive for greater ecological sustainability, while we develop biomass sources on a plantation scale that can serve as alternatives to fossil fuels.”
“We must also continue to work on solutions to current legal and market barriers that make large-scale research and commercial use for genetically modified trees difficult.”
WHAT IS CRISPR-CAS9?
CRISPR-Cas9 is a tool for the accurate processing of DNA discovered in bacteria.
The acronym stands for ‘Clustered Regularly Inter-Spaced Palindromic Repeats’.
The technique includes a DNA cutting enzyme and a small tag that tells the enzyme where to cut.
The CRISPR / Cas9 technique uses tags that identify the location of the mutation, and an enzyme that acts as a small pair of scissors to cut DNA in a precise location, allowing small parts of a gene to be removed
By editing this tag, scientists can target the enzyme to specific DNA regions and cut exactly where they want.
It has been used to ‘silence’ genes – effectively eliminating them.
When cellular machines repair the DNA break, it removes a small piece of DNA.
In this way researchers can precisely switch off specific genes in the genome.
The approach has previously been used to process the HBB gene responsible for a condition called β-thalassemia.
According to Professor Strauss, sustainable forest management systems and their certification bodies assume that ‘genetically modified’ is dangerous.
“If something is a genetically modified organism, it’s guilty until it’s safe in the minds of many and in our prescriptions today,” he added.
“These technologies are new tools that require scientific research to evaluate and refine them case by case.”
“We have an enormous need for extensive production of sustainable and renewable forest products and ecological services and biotechnologies can help meet that need.”
The full findings of the study were published in the Proceedings of the National Academy of Sciences.