by Marcia Goodrich
It was not what postdoctoral researcher Chung-Jui Tsai and her colleagues expected when they peeled away the bark on their aspen saplings. What they expected was nothing much. When it's your job to alter tree genetics, trying to make them easier to pulp, you have to analyze a lot of wood. Peeling bark gets about as routine as inhaling.
Yet this time, Tsai could scarcely catch her breath. The wood she exposed was not like any aspen she had seen. All other aspens had been white. These were red.
Well, more of a salmon color, really. Pinkish gold. Rosier than cedar, less red than redwood, a color Professor Vincent Chiang, who leads the research group, calls "very distinguished." And it varies from tree to tree, in hue, intensity, and design. Some of the saplings, not much bigger around than a finger, are mottled, spotted "like a dalmatian," red and white.
And the new color won't sink back into the gene pool, never to be seen again. It has remained true in the saplings Tsai and forestry master's student Melissa Mielke have grown from cuttings taken from the original fifteen.
Aspen, traditionally harvested for pulp, has never been a popular wood for lumber. "It's a kind of boring, white color," explains Chiang, a world leader in the genetic engineering of trees. Now it will have other, non-paper uses. He counts the ways. "Furniture, exposed beams, paneling . . . I'm looking forward to the day that I don't have to paint the house." He has talked with four wood products corporations about growing the red aspens. "They've all responded vigorously."
The trees are, so far as anyone knows, unlike any aspen, anywhere. They are an amazing accident of genetic engineering, a serendipitous side effect of Chiang's ambitious efforts to design better trees for making pulp and paper.
Chiang, director of Michigan Tech's School of Forestry and Wood Product's Plant Biotechnology Center, has garnered millions in research grants to genetically alter lignin, the portion of wood that makes it stiff. His goal has been to make lignin easier to break down in the manufacturing of pulp. Such a move could not only save industry billions of dollars, it could also help protect the environment by reducing the need for some toxic chemicals in the pulp- and paper-making process.
His lignin work could provide tremendous breakthroughs for the forest-products industry worldwide. But, the researchers note, it lacks the charisma of colored aspen.
"You don't need to analyze [the red aspen]," Chiang said. "You just look at it, and there it is."
"Usually you have to wait years for results," said Tsai. "We just pulled back the bark, and wow!
"Even a kid can tell."
Chiang credits Tsai for developing the genetic engineering procedures for aspen, a project that took her only eight months. And, in experiments with Associate Professor Gopi Podilla, of Michigan Tech's biological sciences department, she introduced two different genes designed to alter the cloned aspens' lignin.
They'd like to gain a fundamental understanding as to how this color change happens. And they also want to try out their red-wood gene on other species-it affects a genetic pathway that's common to many hardwoods.
The researchers have applied for a license from the U.S. Department of Agriculture to plant the red aspen outside, so the trees can be studied as they grow to maturity in a natural environment. They also are filing for immediate patent protection of their process through MTU's Intellectual Properties Office.
And, they are dreaming very seriously of another, related project.
"The next target will be bird's-eye maple," Chiang asserts. "I'm not kidding. If we could engineer bird's-eye . . . "
Their lignin research has produced another surprise: a tiny aspen Tsai has named "Baby Tree."
Baby Tree was born as the result of a genetic engineering experiment designed to change the proportion of two components of lignin, syringyl and guaiacyl. Theory has had it that the more syringyl in the syringyl/guaiacyl mix, the easier it is to remove the lignin. Normally, the ratio of syringyl to guaiacyl in aspen is 2.2:1.
To test the theory, they engineered aspen trees in an effort to cut down syringyl production.
"In one case, we reduced syringyl by 50 percent," Chiang said. "In Baby Tree, the ratio is only .88:1. And 60 percent of the lignin can be removed from a normal tree, but in Baby Tree, you can only remove 11 percent. It proves our hypothesis."
Unlike the red aspen, Baby Tree seems to be an anomaly. "So far, we have produced hundreds of transgenic aspen, eucalyptus, and sweet-gum trees containing a variety of introduced genes (lignin-related genes mostly), and Baby Tree is the only one that shows marked defect in a normal growth pattern," Chiang said.
Now, they're planning to reverse the experiment and engineer pulp-friendly trees with lots more syringyl. And, like the red aspen, Baby Tree has opened up a whole new world of inquiry.
"Tree growth is another area we want to get into," Tsai said. "It could be that Baby Tree's growth function was retarded by blocking a growth-related gene."
If they can tag that gene and replace it with a growth-promoting gene, Chiang and Tsai could add Papa Tree to their collection. "We could make it grow like crazy," Chiang said.
ELF waves: fertilizer of the future?
The weather in Chandrashekhar Joshi's small acacia nursery in MTU's Plant Biotechnology Center is as close to the tropics as you can get without actually being there. Its light, temperature, and humidity mimic South Sea island climate, and on a bad-weather day at Michigan Tech, the temptation is to fling all the young trees out onto the cold ground and crawl in yourself.
But you probably shouldn't. The only non-tropical variable in this enclosed, tanning-booth-size incubator is ELF waves, and some studies show they could cause cancer.
Inside, the Extremely Low Frequency radio waves form magnetic fields of varying intensity (0 mG, 5 mG, 15 mG, and 30 mG) around each of four rows of acacias. And the most casual inspection shows that something major is going on: the trees in the center look like showpieces for a fertilizer commercial.
ELF waves on a grander scale have been an object of interest and protest in Michigan's Upper Peninsula since the late 1970s, when the U.S. Navy decided to build a miles-long ELF transmitter to communicate with undersea nuclear submarines. Opponents feared unknown environmental consequences to the forest and its wildlife.
Nevertheless, the transmitter was built, and a subsequent ten-year field study of the effects of ELF on the environment revealed no harmful effects. But research by forestry professors Glenn Mroz and David Reed yielded an eye-opening conclusion: ELF can make trees grow bigger. Lots bigger. Aspen grew 48 percent faster in an electromagnetic field, while red maple shot up an astonishing 72 percent faster.
Joshi, a research assistant professor at the Plant Biotechnology Center, is testing their findings in his little tree incubator, seeing if ELF affects lab-grown tropical acacias in the same way as it does the cold-loving trees in northern Michigan forests. Other members of the research team are center director Chiang, Podilla, electrical engineering professor Warren Perger, and undergraduate Igor Kostic, also in the electrical engineering department.
Their work is showing that the field study conclusions are, if anything, conservative.
"We are observing tremendously fast growth," Joshi said. "It's extremely amazing."
The control acacias, grown in the 0 mG environment, are about 6 centimeters high. The trees grown in the 15 mG field are twice that big, between 12 and 13 centimeters tall.
And these are no wan, spindly, starved saplings. "They are extremely healthy-looking plants," Joshi said.
Ironically, the ELF-related tree growth may be obliquely related to the increase in cancer linked to prolonged ELF exposure. Joshi speculates that a parallel process may underlay both phenomena.
Most organisms contain a gene that regulates cell division. "In animals, when it's turned off, the cells divide like crazy to form a cancerous tumor," he said. "Plants in electromagnetic fields grow extremely fast but they don't get cancer."
Somehow, plants, unlike people, seem to turn that gene back on and take the ELF-induced growth in stride.
Joshi is hard-pressed to mask his excitement when he talks about his work, both the answers it yields and the questions it raises.
"It's mind-boggling," he said, shaking his head in wonderment. "We are fortunate to have landed on the right problem at the right time. You never know until you do the experiment."
Photo above: Vincent Chiang, director of the Plant Biotechnology Center, examines one of his genetically altered aspens. Trees he'd engineered as part of a completely different experiment surprised researchers by turning red instead.