The genome of the fungus1 that helps mountain pine beetles3 infect and kill lodgepole pines(美国黑松) has been decoded4 in a University of British Columbia study. Also known as blue stain fungus for the stain it leaves in the wood of infected trees, Grosmannia clavigera is carried to the host trees by pine beetles and weakens the trees' natural defense5 system, allowing pine beetles to feed and reproduce in the tree bark(树皮绉) . A successful beetle2-fungus attack ultimately causes tree death.
Now, researchers from UBC and the BC Cancer Agency's Genome Sciences Centre have conducted a detailed6 genome analysis and identified genes7 in Grosmannia clavigera that are responsible for the fungus's ability to bypass the lodgepole pine's natural fungicide – and use it as a carbon source for fungal growth.
The study is published this week in the Proceedings8 of the National Academy of Sciences.
"We found that the fungus cannot only survive, but thrive when exposed to the normally fungicidal resin9(树脂,松香) chemicals of pines," says co-author Joerg Bohlmann, a Distinguished10 University Scholar and professor in the Michael Smith Laboratories at UBC. "In a way, it's like these genes give the fungus the ability to turn poison into nectar(花蜜,甘露) ."
"Our study helps to clarify how the fungus has evolved to successfully infect lodgepole pine and gives us a better understanding of the intricate(复杂的,错综的) chemical interaction between the tree, beetle and fungus," says Bohlmann. "This new knowledge could inform strategies to prevent future outbreaks, such as selecting trees with improved resistance to pine beetles and their associated pathogens."
The current outbreak of mountain pine beetle has destroyed more than 16 million hectares of forest in B.C. – roughly twice the size of New Brunswick or more than 32 million football fields. It has crossed the Rocky Mountains, and is now in the boreal(北方的) pine forests, moving east. The devastation11 of large areas of pine forest is anticipated to have major consequences for global carbon balance and sequestration(隔离,扣押) .