NAU’S MGGen Lab Tracks Lethal Bat Fungus
In the eastern United States and Canada bats have been dying by
the hundreds of thousands—a result of a fungal disease called white-nose
syndrome (WNS) caused by the fungus Geomyces
destructans (Gd). At Northern Arizona University (NAU), Dr. Jeff Foster, Associate
Director of NAU’s Center for Microbial Genetics and Genomics (MGGen), and his
team of five undergraduate students and Postdoctoral Researcher Kevin Drees are
tracking the spread of Gd using genetics.
Although the disease was first discovered in a New York cave
during the winter of 2006, its exact origins are still a mystery. Since then,
the fungus has spread into 19 U.S. states and four Canadian provinces, killing
greater than 5.5 million bats. Because of the far-reaching importance of bats
for pollination and pest control in agriculture and forestry, NAU’s research
has both national and international significance. “Bats provide ... major ecosystem services.
We don’t pay the bats to do this, [but] they go out there and eat millions and
millions of tons of insects that have direct effects on things like agriculture
and mosquito populations. The likelihood is that without bats eating all these
insects, we’re going to be drastically affected,” notes Foster.
“Bats provide ... major ecosystem services. … They go out there
and eat millions and millions of tons of insects that have direct effects on
things like agriculture and mosquito populations.”
The white, cold-loving fungus, which most scientists suspect was
unintentionally transported from Europe, attacks bats when they are hibernating
in caves in the winter. The fungus grows on their faces and wings—giving the
appearance of a “white nose”—and causes them to awaken more often and sooner
than uninfected bats do. Infected bats tend to freeze or starve to death due to
a lack of fat reserves.
The Gd project, which began in 2010, has two key components.
1. Detecting Gd in various samples. Researchers
in the MGGen lab receive from numerous collaborators swabs of bat skin, walls
of caves, and dirt samples, as well as bat feces to “look for the presence of
the fungus down to forensic levels,” says Foster. Detection allows them to see
how Gd interacts with its environment and how it is spreading so that,
theoretically, one does not need a bat to know if Gd has spread to a given
cave. This method shows that Gd may have different effects on different bat
species. For example, the little brown bat (Myotis lucifugus) appears to
have both the highest amount of Gd on infected bats and the highest mortality
rate. By being able to detect exact amounts of the fungus on
samples, researchers can begin to understand whether or not there is a
relationship between the quantity of Gd and mortality.
Since 2010, researchers at NAU have tested more than 5,000 samples
at least two or three times. “Having
lots of collaborators who can assist with things like taking samples and
analyses is imperative,” says Foster.
2. Examining Gd genetics to determine the
fungus’s origin and likely routes of dispersal. By
sequencing genomes, the team can identify relationships between isolates (pure
strains) of the fungus, Foster says, “We will be very happy when and if we find
identical isolates from Europe.” He asserts the genetic similarities between
strains “strongly suggest a single, recent introduction of the fungus [to the
United States, from Europe].”
So how does one account for genetic differences between American
and European isolates of the fungus if they most likely come from the same
help solve the mystery
The Gd fungus has been in Europe for hundreds— if not thousands—of
years, and therefore had time to become genetically diverse there. This makes
finding a European match for the American Gd fungus a trickier task. “If we
find the origin, the genetics should be pretty conclusive,” he says. For this
sleuthing part of the research, Foster and his team have sequenced 30 genomes
in their entirety and sequenced portions of 70 Gd genomes.
Sabrina German, an NAU senior and biomedical science major, has
been working on this project since it began. She spends five days a week in the
lab doing genetic extractions, and often analyzes Gd assay results from home.
German views this research as an educational opportunity: “Working in the lab
and going to school at the same time definitely has its challenges, but things
I’ve learned in class I am now able to directly apply to what I’m doing here
and vice versa.” German added that she enjoys contributing new knowledge to a
subject that is still so vastly unknown.
As biologists across the globe seek to understand Gd and the sudden,
widespread mortality it is causing in North American bats, researchers from
NAU’s own MGGen lab are adding pieces to this consequential puzzle. They hope
to help prevent future devastation of North America’s bat populations.