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Regan's wonder weed
 By Stefan Norman
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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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