November 13, 2009 – As hordes of mountain pine beetles continue to devastate wide swathes of Canadian forests, scientists are intensifying research efforts that may help find ways to better manage these and other hungry forest insect pests, as well as their associated fungal pathogens.
The results could help preserve some of the estimated 15 million hectares currently affected by the mountain pine beetle–territory with immense value as timber resources, recreational areas and wildlife habitat.
University of British Columbia (UBC) biologist Joerg Bohlmann and his team are at the forefront of developing new knowledge about mountain pine beetles and the trees they inhabit at the genomic and molecular biochemical levels. The NSERC-funded researcher has also unearthed valuable clues about the role played by the blue stain fungus – a pathogen that invariably hitches a ride with the mountain pine beetle, and in fact helps the beetle set up residence in a host tree.
In close collaboration with researchers Colette Breuil of UBC’s Department of Wood Science, Richard Hamelin of Natural Resources Canada and Steven Jones of Canada’s Michael Smith Genome Sciences Centre, Dr. Bohlmann’s most recent success involved sequencing the genome of the blue stain fungus.
“Every time you have a genetic blueprint of an organism, you can interpret this information, and you can look for biological processes and mechanisms in these organisms that are highly target specific for possible intervention,” he notes. Among other things, he wants to find the genetic basis for the techniques used by the beetle and the fungus to bypass and disarm the natural defences mounted by conifer trees.
Conifers normally protect themselves from such attacks through complex chemical defences that include producing more resin; an antibiotic, antimicrobial and insecticidal soup that few insects can survive. Mountain pine beetles, however, can actually penetrate the sticky barrier in order to invade the tree.
Dr. Bohlmann believes that the blue stain fungus paves the way by reducing the toxicity of the resin, then makes the interior of the tree more hospitable by choking off its ability to produce more resin and unlocking nutrients from the tree for the beetle to use. That symbiotic, combined attack, rather than just the damage done by the bark beetle, seems to be what actually kills trees.
He is confident that his team’s research can help find new ways to boost a tree’s natural resistance or interrupt the collaboration between beetle and fungus.
The goal, he says, is to restore balance to the ecosystem, with the mountain pine beetle sticking to its natural role of helping rejuvenate Canada’s forest resources by attacking only weaker and older trees.
Dr. Bohlmann says this kind of knowledge can help forest managers make better decisions about planting, harvesting and other management practices, ensuring a more sustainable future for all forest users.