`Super pest' Colorado potato beetle has the genetic resources to
sidestep our attacks
Date:
February 23, 2022
Source:
University of Wisconsin-Madison
Summary:
The Colorado potato beetle has evolved resistance to more than
50 different kinds of insecticides, making the insect a 'super
pest' that wreaks havoc on potatoes around the world. New research
finds that the beetle achieved this feat largely by turning to a
deep pool of diversity within its genome, which allowed different
populations across the U.S. to quickly evolve resistance to nearly
anything humans have thrown at it.
FULL STORY ==========================================================================
The Colorado potato beetle has evolved resistance to more than 50
different kinds of insecticides, making the insect a "super pest" that
wreaks havoc on potatoes around the world.
==========================================================================
New research finds that the beetle achieved this feat largely by turning
to a deep pool of diversity within its genome, which allowed different populations across the U.S. to quickly evolve resistance to nearly
anything humans have thrown at it.
The pest's wealth of diversity and arsenal of existing resistance genes
will likely make it hard to control in the future, regardless of what
new insecticides researchers develop. But the new understanding of the
pest's genomic resources could help scientists design management systems
that keep it in check.
"This beetle was one of the first to be attacked with chemicals in the
modern era, and it's been very successful at evolving past those attacks,"
says Sean Schoville, a University of Wisconsin-Madison professor of
entomology who led the new analysis. "For other insects we're hoping to control, there's lessons to be learned from studying this pest. What
mechanisms does this insect use to get past these insecticides?"
Along with his collaborators at UW-Madison and other institutions,
Schoville published his findings Jan. 19 in the journal Molecular Biology
and Evolution.
Schoville's team first sequenced the Colorado potato beetle's genome
in 2018.
Since then, they've probed the genome to understand how the insect can
overcome new insecticides as quickly as it does. To do so, they sequenced several dozen beetles from across the U.S. These regional populations
vary in what pesticides they are resistant to and where they came from,
which can give clues to the evolutionary history of the pest.
==========================================================================
The scientists discovered that these different regional groups evolved
so quickly because their parent populations already had the genetic
resources necessary to overcome insecticides.
"The genes that evolve are well known to be involved in insect
resistance. But what's interesting is that different populations are
altering different parts of genes or different genes in the same pathway,"
says Schoville. This similar, but not identical, pathway to resistance
across different populations is known as repeated evolution.
This rapid evolution based on a wealth of existing genetic diversity is
at odds with an older model of evolution that assumed rare mutations have
to slowly arise in a population. While new mutations do develop and can contribute to insecticide resistance, the potato beetle's rapid response
to new chemicals in different parts of the country can be explained only
by its existing diversity.
The findings are unwelcome news for farmers and scientists hoping to turn
the tide on the potato beetle's attacks. It seems unlikely, Schoville
says, that even a brand-new insecticide would keep the pest in check
for long.
But armed with the knowledge of how the Colorado potato beetle has
sidestepped our attacks, future research might help produce creative
strategies to keep pace with this nemesis.
"More sophisticated models might help us learn how different management techniques affect the beetle's evolution. That might allow us to change
our management style to slow it down," says Schoville.
This work was supported in part by the U.S. Department of Agriculture
(grants 2015-67030- 23495 and 58-5090-7-073) and two Hatch Awards
(grants WIS02004 and VT-H02010).
========================================================================== Story Source: Materials provided
by University_of_Wisconsin-Madison. Original written by Eric
Hamilton. Note: Content may be edited for style and length.
========================================================================== Journal Reference:
1. Benjamin Pe'lissie', Yolanda H Chen, Zachary P Cohen, Michael
S Crossley,
David J Hawthorne, Victor Izzo, Sean D Schoville. Genome
Resequencing Reveals Rapid, Repeated Evolution in the Colorado
Potato Beetle.
Molecular Biology and Evolution, 2022; 39 (2) DOI:
10.1093/molbev/msac016 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/02/220223104922.htm
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