White spruces in
Eastern North America have been devastated by spruce budworms. These are moths whose
caterpillars are dangerous to spruce populations due to their consumption of
white spruce needles and balsam fir. The most recent paramount invasion by this
species occurred between 1970 and 1990, resulting in the loss of half a million
cubic meters of wood in just Quebec alone. Conifer trees continue to be
negatively affected by the existence of spruce budworms, although scientists have
come much closer to solving this problem with a recent discovery.
Researchers from
the University of Oxford, the University of British Columbia, and Université
Laval have uncovered a gene in white spruces that provides natural resistance
to the spruce budworm. This was done through analysis in which the researchers
compared the genomes of the more resilient trees to those that were more
negatively impacted by the feeding activity of the spruce budworms. They found
that the betaglucosidase-1 gene had much higher levels, about 1,000 times
higher, of gene expression in the resistant conifers than the non-resistant ones. The
protein encoded by this gene was isolated, and found to contribute to chemical
reactions that ultimately produce two compounds that have shown to be toxic to
the spruce budworm. Thus, those trees with increased levels of expression of
the gene that encodes this protein are more resistant to the budworm due to
high production of what is essentially a natural insecticide.
The
betaglucosidase-1 gene is present in all individuals of the white spruce
population; however, only certain trees have a high enough level of expression
to provide for sufficient resistance to the harmful spruce budworm. Scientists
believe that they can utilize this information to create white spruces that
experience increased expression of this gene, so that they remain resistant to
this insect invader. This would prevent the further destruction of these large
forests of white spruce conifers.
I find this
article to be very interesting. Normally when looking into genetic studies, I
have seen many examples of different alleles for genes or mutations to genes
that result in differences among various organisms in a population. For this
scientific discovery, the various individuals of the white spruce population
all have the gene interest (the betaglucosidase-1 gene); however, the differing
level of expression of the gene to encode the protein makes the difference. I
find it fascinating that there is 1,000 times greater expression of the gene,
and that this provides for production of enough of the protein to give the
conifers resistance through production of a natural insecticide. Hopefully this
information will allow researchers to be successful in protecting white spruce
populations from the spruce budworms.
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