52 THE SCIENTIST | the-scientist.com
FOUNDATIONSW.R. FISHER, CORNELL UNIVERSITYBY MAX KOZLOVViral Discoveries, 1929
I
n 1925, after years of study and research,
Helen Purdy Beale seemed to be on
track to become the first woman to
graduate with a doctorate from Cor-
nell University’s plant pathology depart-
ment. Her final hurdle was to obtain the
approval of her adviser, Herbert Whetzel,
who, unbeknownst to her, had dissuaded
previous female graduate students from
obtaining PhDs on the grounds that over-
qualified women could not get hired at
agricultural experimental stations. True
to form, Whetzel told Beale that her the-
sis could not be accepted and returned
it, heavily marked up with red ink. Beale
hurled the pages into his face, screaming,
“You have shown the claws of the devil!”
and stormed out, according to an account
by virologist Karl Maramorosch. Beale
would go on to earn her doctorate from
Columbia University in 1929 and change
the course of plant virology with her work
on tobacco mosaic virus (TMV).
TMV had been discovered only in the
late 19th century, when chemist Adolf
Mayer noticed that some tobacco plant
leaves developed multicolored splotches
and eventually shriveled up. Viruses were
little-understood at the time, in part
because, unlike bacteria, they couldn’t be
seen with a light microscope. Mayer and
other scientists ascribed the condition to
parasites, enzymes, or other substances
that they were unable to characterize in
the plants, and could only diagnose TMV
using the rudimentary technique of look-
ing at diseased plants’ symptoms. Beale set
out to change that.
After graduating from Columbia, Beale
returned to the Boyce Thompson Institute
(BTI) in Yonkers, New York, where she’d
previously worked as a plant pathologist
for a few years. She postulated that a
substance in animal serum—today known
as antibodies—could be used to study
plant viruses. Indeed, Beale found that the
serum of rabbits that were injected with
TMV-infected sap could then be mixedwith samples of sap from other plants to
test whether they were also infected: only
TMV-infected sap would form a heavy
precipitate (made of antibody-bound virus)
when mixed with the serum. Different plant
species infected by the virus yielded similar
precipitates, indicating that the disease
did not arise from a defect of the plants
themselves, but was caused by an infectious
agent. Beale subsequently found that the
precipitate formation was specific to TMV,
and she devised assays to determine viral
concentration—methods that were among
the first serological techniques in virology.
Yet Beale’s work went largely unnoticed
for at least 30 years. Texas A&M Univer-
sity virologist Karen-Beth Scholthof, who
has written about Beale’s contributions to
the field and describes her as the “mother
of plant virology and serology,” notes that
plant pathologists were still using the tools
and methods of the early 20th century as
late as the 1960s before they rediscovered
Beale’s experiments and began using herassays, the fundamentals of which are still
used today. Frederick Charles Bawden, a
plant pathologist, wrote in 1970: “I still
remain puzzled to understand how it was
that so many virus workers long remained
reluctant to use these invaluable tech-
niques. With hindsight, it is very evident
they were even more valuable than those
of us who used them appreciated.”
Scholthof says last year’s rapid
COVID-19 test development owes a debt
to Beale’s foundational ideas from a cen-
tury ago. “Then and now, serology is really
important for understanding more about
the biology of these viruses, where they
are localizing in cells, and having rapid
diagnostics,” she says.
Beale remained at BTI for several
decades and, after her retirement, com-
piled a 1,500-page bibliography with
more than 29,000 plant virology refer-
ences. She died in 1976. Her Ridgefield
Press obituary described her as “unflap-
pable, witty, and persevering.” JSAY CHEESE: Helen Purdy Beale (front row, in the fur coat) poses for a photo in 1919 with her
mycology class at Cornell University, where she began her graduate work in plant pathology.