May/June 2021 - 26

The Potato Association of America mission statement: The PAA and
its allied associations must strongly support the private sector through
Extension, research and commercialization efforts aimed at enhancing
the role of the potato as the premier food source for the 21st century.
New tools, approaches may yield
potato beetle-resistant varieties
By Natalie Kaiser and
Dave Douches
Potato Association of America
T
he Colorado potato beetle is a
major pest in North America
that can reduce potato yields
by 30-50% if unchecked. Control has
historically relied heavily upon the use
of pesticides, but failure of chemical
control against Colorado potato beetle
has been reported for most major
classes of synthetic insecticides.
Since the 1980s, we have known that
Solanum chacoense, a wild species
from Argentina, was highly resistant
to Colorado potato beetle. U.S. and
Canadian breeders have attempted to
breed beetle resistant varieties, but it
has been difficult to transfer the strong
resistance we see in wild relatives into
commercial varieties.
Michigan State University has
followed in the footsteps of the
previous potato researchers and has
been working on this challenge using
research tools optimized in potato for
more than a decade, such as genomics
and gene editing. Combining these
tools with a new breeding strategy that
simplifies potato breeding has allowed
us to make advances that put beetle
resistant varieties within grasp.
Wild potato relatives
naturally make their own
insecticidal compounds
to keep pests like the
Colorado potato beetle
at bay.
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Spudman.com
Figure 1. Graduate student Natalie Kaiser next to the beetle resistant wild potato relative
80-1 that remains untouched in the field (left). Researchers Kate Shaw and Chen Zhang
(right) rate Colorado potato beetle defoliation in a field trial.
Wild potato relatives naturally make
their own insecticidal compounds to
keep pests like the Colorado potato beetle
at bay. Different wild species produce
unique versions of these compounds
known as glycoalkaloids. Some are
so effective they cause mortality in
Colorado potato beetle larvae and
dramatically reduce adult beetle feeding.
Glycoalkaloid production in potato
leaves is advantageous for warding off
hungry beetles, but consuming large
amounts of glycoalkaloids can cause
adverse health effects in humans.
For this reason, Professor David
Douches and graduate student Natalie
Kaiser at Michigan State University
are working to create potato
varieties that synthesize a powerful
glycoalkaloid called leptine only in the
leaves of the potato.
By comparing the chemical profile
of hundreds of individual potatoes
with their resistance to the Colorado
potato beetle in the field, Kaiser also
found chemical signatures that could
predict field performance. This means
that breeders can select resistant
potatoes with a simple chemical
measurement instead of having to
conduct a field trial.
Researchers have tried to introduce
of
production
potent
leptine
glycoalkaloids to potato cultivars before
and run into several obstacles. For
starters, there are a great number of
genes controlling the types and amounts
of glycoalkaloids that any given potato
variety will produce. Getting the exact
combination of genes is crucial. To better
track all the genetic players, the Douches
lab sequenced the whole genome of

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May/June 2021

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