Critics warn of unpredictable effects
In spite of the opening of the article below, which posits a situation where GM ash trees could replace those that are expected to die from a fungal disease, it’s useful to remember that:
- No GMO solution exists to ash die-back disease and one may never be found.
- In any tree disease epidemic, some trees are unaffected and can be used in a conventional breeding programme to develop a new resistant population. Despite claims by GMO proponents that GM could save the elm tree, which had been devastated by Dutch elm disease, the GM variety was not tested for disease-resistance over the long term. The approach that was finally adopted is based on natural breeding of resistant elm cultivars.
- The researchers are rightly considering different options, including natural breeding programmes.
- Contrary to a claim made in the article below, GM is no quicker than conventional breeding, and the latter can be sped up further by marker assisted selection.
In the article, unnamed scientists claim that ash trees genetically engineered through cisgenesis “would contain only ash genes”.
A public survey set up to evaluate people’s response to the options regarding the ash crisis is cited as evidence that cisgenesis enjoys greater public acceptance than old-fashioned transgenesis, where the genes of interest come from a different species from the one that is being genetically engineered.
But the claim that led the public survey participants to that conclusion is likely false.
This is because cisgenesis normally involves the introduction of foreign genes, albeit the gene of interest may come from an organism that is the same as, or is closely related to, the one that is being genetically engineered.
Cisgenesis, just like transgenesis, involves the highly mutagenic processes of gene insertion and tissue culture.
So regarding cisgenesis, the unnamed “scientists” have misled the public who took part in the survey.
With 90% of the UK’s ash trees about to be wiped out, could GM be the answer?
The Guardian, 31 Oct 2015
* Scientists have proposed a radical solution to help trees develop resistance to ash dieback. But critics fear there could be unpredictable effects
Genetically modified ash trees could replace the 80 million expected to die in the next 20 years from a deadly fungus, scientists have proposed.
The radical solution to the greatest woodland disaster of the last 50 years is being explored by research teams at London and Oxford universities with backing from the Department for Environment, Food and Rural Affairs, science bodies and the Forestry Commission.
With no hope of saving existing native ash trees from the “dieback” disease now spreading across the country, a GM solution could develop resistance faster than traditional breeding and start to repopulate woodlands within a few years, say scientists at Queen Mary, University of London.
The fungus, Hymenoscyphus fraxineus (previously called Chalara fraxinea – the disease is also known as chalara), causes leaf loss and crown dieback and has already wiped out 90% of ash trees in Denmark. It was first confirmed in the UK in 2012 and is expected to wipe out 90% of the ash population, which accounts for 20% of all UK trees.
Following a £7m government grant to study ash dieback, six breeding techniques to replace the trees have been put forward by Queen Mary biologists. These have been presented by Oxford scientists to groups of landowners, ecologists, tree specialists and others to gauge public opinion.
“It’s early days,” said Richard Buggs, lecturer in biological sciences at Queen Mary, who is sequencing the ash tree genome. “We don’t want to invest a lot of effort in developing GM ash trees no one wants. There are different options. We could use GM, or hybridise them, or back-cross them. We are looking at all 35 ash species in the world. Some which are resistant to ash dieback come from China.
“I see GM as one of several possibilities to explore both scientifically and with regard to public acceptability but I have not formed conclusions on whether it is a good choice or not. My current research is not developing a GM ash; it is simply trying to find genes within the ash genus for resistance to ash dieback,” said Buggs.
“If we discovered that people did not want GM [ash] and rather had no ash there would be no point developing a GM ash, and we would pursue a breeding approach. Potentially it could be quicker to develop GM trees resistant to ash dieback. Conventional breeding would take many decades,” he said.
A survey of 1,400 people revealed a mixed reaction to the prospect of GM ash trees, said Oxford University researcher Irina Arakelyan. “The three options with the highest acceptability were breeding native tolerant ash, using accelerated breeding to breed native tolerant ash, and cross-breeding of native ash with non-native ash.
“The two least preferred options, which were almost equally unpopular, were a ‘no-action’ option to let nature take its course with the disease, and trans-genetics which would introduce a gene from another plant or animal into native ash trees,” she said.
But one of the most popular options was a GM method called “cis-genetics”, which transfers genes between different species of the same plant. Because ash trees genetically engineered in this way would contain only ash genes, scientists believe public objections would be less strong. The method was used in the US to develop poplars and GM chestnut trees which were decimated by a deadly fungus accidentally imported from Asia 100 years ago. By the 1950s the American chestnut had been almost wiped out. However, opposition to it and other GM trees in the US has led to the project being shelved.
GM trees are seen by some as a potentially lucrative development, able to speed growth and increase volume in plantations. But only three types of GM trees have so far been authorised for commercial use anywhere in the world, and little is known about how they might react in mixed forests. China has planted some GM trees, Brazil is close to planting eucalyptus and the US authorities are considering a request to plant a poplar.
Some ecologists and geneticists argue that the unregulated release of any GM trees in a forest or woodland could do massive damage. “A forest ecosystem is wildly complex and biodiverse, with little known about the natural interactions between soils, fungi, insects, understory plants, wildlife and trees. Any attempt to engineer genomes by invasive methods can cause unexpected effects. Cis-genesis is still genetic engineering and subject to unpredictable effects,” said Anne Petermann, director of the Global Justice Ecology Project.
“It would open the door to GM trees in Europe if Britain decided to go ahead,” she said. But others say that British trees like the ash face such a variety of pests that it is essential that every method be tried to save them for posterity.
The director of conservation at the Woodland Trust, Austin Brady, urged caution: “The test tube should be the last resort, only used when we have exhausted all the other options. We would steer away from any direct insertion or manipulation of genes until we have harnessed all the natural processes.”
The trust is working with Defra and the Forestry Commission to try to identify native ash trees that are resistant to dieback. It has planted 24,000 ash trees, gathered from all over the UK, to expose them to the disease to see which, if any, are suitable to be bred from.
Friends of the Earth chief executive Craig Bennett said: “This is not solving the original problem which was caused by the international horticulture trade. The science of the lab is very different from the science of the landscape. You have to be hugely cautious and be aware of unintended consequences. This could fundamentally change what we think of as nature.”
Paul Jepson of the University of Oxford school of geography and the environment said: “Tree diseases threaten the look and economy of the countryside. This situation needs a ‘talk it through’ approach to science: where scientists present the range of possible tree planting solutions and ask citizens what they think. It is about giving science and policy a steer.”
A Defra spokesperson said: “We want to ensure that the graceful ash tree continues to have a place in our environment. That’s why we’re protecting non-infected areas, managing affected plants and have invested over £21m into tree health research – including developing disease-tolerant ash trees though selective breeding.
“Defra is not developing GM trees.”