One of the first GM 'decontaminations' by activists in the UK was carried out in 1999 when two field trials of 115 GM poplar trees were trashed.
The reasons given for this action were blunt:
"those who are manipulating the DNA of trees using a very powerful but dimly understood technology, show contempt for our planet and the life it supports, including human life".
Media warnings were succinct: GM trees could lead to "a
silent spring in the forests of the future".
Until the activists struck, Britain was intent on becoming a
world leader in GM trees.
Since then, GM trees for commercial cropping, for example
'arctic' non-browning apples and superfast growing eucalyptus for paper,
plastics and biofuel production, have been under development in the UK and
around the world [1]. These are intended
for confined sites.
The latest GM tree venture to surface was also a British
idea and is much more ominous, more contemptuous of Nature and more than ever
likely to lead to a "silent spring": a GM forest tree intended
specifically to spread freely through the wild.
During the first half of the 20th Century, the American
chestnut tree, once a dominant species in North American forests, was decimated
by a fungal blight and by logging.
Genetic engineers have created GM American chestnut trees
which can limit the spread of the fungus within them and so make the infection
less lethal. The theory is simple: the
blight produces an acid which breaks down the tree tissue preparatory to
invasion; the GM trees have an artificial gene copied from wheat for an enzyme
which denatures the fungal acid and prevents the invasion. This tactic isn't new, the research goes back
twenty years. It's been tried and found
effective in peanuts, soyabeans, canola and poplar trees, but none, it seems,
have been found effective enough to be worth commercialising (yet).
If approved for release, GM American chestnut trees are
intended to become a dominant species in North American forests, where they
pose layer upon layer of concerns.
Trees are very big (they take up lots of space), they grow
very slowly and have a very long life-span (they're around a long time); their
interactions with the surrounding dynamic ecosystems (climate, air, weather,
soil, plants, animals and microbes) are far-reaching, time-dependent and
immensely complex. A technique, like
genetic modification, which relies on mass transformations followed by elimination
of the vast numbers of failures is not practical in the case of trees.
Little information about the inserted DNA constructs is
available, but we do know that the plant pathogen, Agrobacterium, was used as
the vector: this technique is known to cause unintended disruption in the structure
and function of the genome. Repeated
back-crossing with non-GM strains for several generations to dilute out the
unwanted changes, as can be carried out with GM crop plants, is not possible
with trees.
GM trees in confined orchards or stands for fast-cropping
don't have to be like their natural ancestors, but the trees proposed for
re-population of, and interaction with, the North American forests are going to
be very different from the old chestnut trees.
Genetic modification for pathogen resistance in crop plants
is proving to have a short shelf-life: successful pathogens have a great
capacity to evolve, especially when their hosts' defence mechanisms are
simplistic. Genetic engineers try to get
round this using fresh waves of GM traits and stacking the old traits together
in one plant. Given the disparity in
generation time of the American chestnut trees (hundreds of years) and blight
(weeks), there's no doubt the pathogen will outsmart the genetic engineers and
make a come-back in a new form.
Moreover, since the GM trait doesn't kill the fungus but simply limits
its spread, it would seem to provide a perfect scenario for evolution.
**Note. Genetic engineers already know that a single artificial gene won't, on its own, be effective in conferring durable blight resistance. They anticipate the need for a suite of genes. One of the American chestnut researchers spells out their plans: "Eventually we hope to fortify American chestnuts with many different genes that confer resistance in distinct ways. Then, even if the fungus evolves new weapons against one of the engineered defences, the trees will not be helpless".
Given a pathogen with a potential to evolve every few weeks, how realistic is this?
The current optimism that the GM technology will work is
based on an extrapolation from very young (15-year old) American chestnut trees
(which are naturally more resistant to blight because they're young) to older
trees with a different (older) physiology, different environmental conditions and,
inevitably, an evolved blight to deal with.
No one seems to be considering the health effects of GM
chestnuts on potential consumers or of GM pollen on potential
air-breathers. The artificial enzyme
breaks the fungal acid down to hydrogen peroxide, an unstable but highly
reactive substance damaging to microbes: knock-on effects on gut and surface
microflora, both essential to the health of organisms, are not being assessed.
The biggest alarm bell ringing here is that the GM American
chestnut tree is clearly being promoted as a test case to sway public opinion
towards supporting the use of biotechnology for nature conservation, and
pave the way for the introduction of more GMOs.
This was the same PR angle dreamed up by UK genetic engineers to solve
what they claimed were 'knee-jerk responses' of conservation groups to the very
mention of GM trees.
Regulatory agencies are ill-equipped to evaluate the risks
of a GM tree intended for deliberate spread through wild areas. We have minimal
knowledge of highly complex and dynamic forest ecosystems, monitoring the GM
trees' effects will be impossible, and they will cross national and political
boundaries.
And another thing ...
The profound importance of specific areas and particular
trees in many indigenous cultures isn't compatible with biotech forests. With a fungus to blame, no one's talking about the role of
excessive logging in removing all the healthiest American chestnut trees in the
first place.
OUR COMMENT
It seems the once-mighty American chestnut tree is set to be the golden rice of the forest. Take action to make sure the PR stunt falls flat. Join 'Stop GE Trees' in opposing the approval of the GM American chestnut. Check out https://stopgetrees.org/chestnut/
The Campaign to STOP GE Trees is an international alliance of organisations that united in 2004 to stop the release of genetically engineered trees in order to prevent the anticipated ecologically and socially devastating impacts
Background
[1] GM TREES ON THE MARCH - July 2017
- Biotechnology for Forest Health: The Test Case of the Genetically Engineered American Chestnut, https://stopgetrees.org, 23.04.19
- Jasper Copping, Bid to plant genetically-modified trees in UK, Telegraph, 9.08.08
No comments:
Post a Comment
Thanks for your comment. All comments are moderated before they are published.