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| Sharon Regan is using the wonder weed
Arabidopsis to unwind the genetic secrets of the
poplar. | Pulling one of the weeds from the soil,
Regan points to a pale-coloured portion of the plant located
just above its root and explains that's where its
xylem is located — a woody tissue similar to
that found in trees such as poplar.
That tissue was
first discovered in the weed in 1996 by one of her former
co-workers. Bolstered by that knowledge, other plant
biotechnologists such as Regan are now able to watch
wood formation on this smaller scale.
However the plant biotechnologist
with a tree fetish does face some other battles.
Deep-rooted plant
problems
"There's
been a focus away from tree breeding projects in this
country," says Linda DeVerno, a biological sciences
analyst with the Canadian Forest Service. "There
are fewer of them in Canada."
She says government cutbacks are
partly to blame, but also notes that universities are no
longer hiring people intimate with the genetic and
biological makeup of trees.
DeVerno says another
problem is that industry fears being associated with research
directed at developing genetically-modified trees because of
the potential public backlash—even though there aren't any GM
trees yet available
for cultivation.
John MacKay, a professor at
l'Université Laval, is also studying the question of wood
formation. In particular, he's examined questions related to
wood texture and density.
"There's not a lot of
this type of research being done right now. It's
not desirable," he explains, adding that he too believes
the big reason is the public distaste for any type of research
associated with genetic engineering.
As a result, he says his research
is geared toward selecting superior trees from the wild
rather than genetic modification.
Regan is also quick to point out
that her work has nothing to do with genetic modification. She
explains that mutants occur naturally, and she simply wants to
use them to select for better wood-producing
trees.
In short, she says she has no desire to
put genetically-modified trees into the ground because she
feels existing trees are already up to the
task.
The chore is to find the trees
that are best-suited to cultivation.
Finding forest
researchers
Regan's quest for the ideal tree
has taken her to a few stops before Carleton. She had
worked at the Petawawa National Forestry Institute until it
closed its doors in 1996 because of a lack of federal
funding.
She then moved on to the Swedish
University of Agricultural Sciences to concentrate on
questions of wood formation.
"When Petawawa closed, I
wanted to work in the best forestry group in the
world, and that was this group in Sweden," explains
Regan.
She adds that in Sweden, 94
per cent of forestry occurs on controlled plantation-type
plots. The remaining six per cent is comprised of a few
protected areas and trees that occur within city
limits.
"There's no old-growth forest," says
Regan, suggesting that's one reason why forestry-related
biotechnology has taken off in the country.
In
1999, Regan returned to her native New Brunswick to become
research director for Solanum Genomics International Inc,
a company specializing in potato genomics research and
development.
She explains that while we've
been selecting plants for generations and cultivating
them, we're still trailing behind in areas such as
forestry.
Again, Sweden is the
exception.
"They were forced to manage a long time
ago," says Regan. "I think we have twenty-five times more
land than they do. So we haven't managed to ruin our land
as much as they initially did. But they've taken a huge
initiative to reforest it.
"As far as management
practices, I would say they're further ahead
because they're forced to manage."
Regan reaches
across her desk for a photo featuring row after row of tall,
robust spruce trees grown on a managed
plantation.
"There's so much wood per tree," she
notes, "and it's not a monoculture."
Regan adds that
much of harvesting is in turn done in small cubes as opposed
to traditional methods of large-scale
clear-cutting.
"They spend a lot of time
researching how much they can clear-cut and still
maintain the wildlife."
She adds that one of the
plantations even extended into her very own
backyard. "It's been like this for a hundred years, so no
one remembers it being any different."
As opposed
to the Swedish case, Regan says she hopes forest management
will eventually offer some level of protection to
natural, old-growth forests.
But she's not holding her
breath just yet. "Here we still have so much land that it's a
little bit hard to convince forest companies to go for
plantations rather natural forests which are so rich with all
these different kinds of trees," says Regan.
"Ultimately, we're going to
have to do that. If we can restrict our forestry to
plantations, then maybe in the long run we can preserve
our natural forests. I think it's the only way to
go."
She says that's the basic motivation for
much of the work she's currently doing with
Arabidopsis.
"You can mutate almost any gene in the
plant that is turn it on or turn it off, whatever we
want," Regan points out.
"We can insert nonsense DNA right
in the middle of the gene. The idea is not to make
transgenic trees, but to understand how a gene works and
what its role is. If you can turn it off and on under your own
control, you can get a good idea of what it's
doing."
But there's still the problem of initiating the
transfer of genetic information. Regan figures the best
way to go about it is to hitch a ride.
"You can use a
number of mechanisms. The main one is using a bacterium
called agrobacterium. It's an interesting system where
bacteria will transfer its DNA to a plant.
So
we've exploited that system and we can get this bacteria to
put any gene we want into a plant."
Agrobacterium
often live in symbiosis with plants like Arabidopsis,
occurring in crown galls or bumps near the root of the
plant.
The bacterium uses a method of
DNA transfer to stimulate cell growth and division in an
effort to make itself at
home.
Regan explains that, operating on an
educated hunch, she simply replaces the gene to be transferred
with the gene she suspects to have a role in wood
formation.
In Arabidopsis, the results of the
mutation appear in about eight weeks. It would take two
years to obtain similar results in poplar. So far her approach
seems to be working.
"I found a gene that when we
turned it off, it increased wood production
in Arabidopsis by 50 per cent," says Regan, adding
that she thinks she's already found a similar gene or
homologue for poplar thanks to sequencing work taking place in
Sweden and at the University of British
Colombia.
In the long run, she hopes discoveries like
this one will begin to get industry attention and funding
for research like hers.
"This research is just going to
tackle the basic questions and try and find out how wood
is formed," says Regan. "Let's say there are twenty key genes
that are important. You can use this information to go out in
natural populations and select for trees that have those
twenty genes. Then you can use those as breeding parents. Down
the road this could lead to plantation forestry for sure.
It's a way of thinking of trees as a crop rather than a
forest."
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