If you're a regular reader
of this column, one fact you've probably figured out about
me: I love to bake. As a matter of fact, if you get up in
the wee hours before dawn and stare intently toward the
northeast, that dull glow you see on the horizon isn't some
astronomical phenomenon; it's just my oven blazing away
like a blast furnace! (That's only partially a joke.)
And if you, like me, like to bake, you've probably noticed
a jump in wheat prices — and I don't mean a little
jump, I mean a leaping-the-Grand-Canyon type of jump. Global
wheat prices are at an all-time high; in the past two weeks,
for example, the price per box for my favorite whole-wheat
pasta shot up 149 percent. Talk about "sticker shock"!
So obviously, it's important to protect our American wheat
crop and get the most from it. That's where the scientists
of the Agricultural Research Service (ARS) are looking out
for us — and turning to a surprising ally in the process.
The villain in this story is a fungus called Fusarium graminearum,
and it causes a disease with the hideous name of "scab"
(or, if you prefer to be more formal, Fusarium head blight)
in not only wheat, but also barley and other cereal crops.
It's a nasty disease that cripples the growth of the wheat
kernels and turns them a chalky white.
What could go up against such a formidable foe? The newest
secret weapon, the ARS scientists say, may be lurking in
flowers.
I 'm talking here about bacteria — specifically, bacteria
that hang around the flowers' anthers, the parts of the
flower that make pollen. It turns out that those anthers
also ooze a tantalizing smorgasbord of nutrients (that is
to say, "tantalizing" if you're a bacterium).
One of these nutrients is called choline, and the bacteria
need that one for growth.
In greenhouse studies and field tests in Illinois and Ohio
starting in 2002, the ARS scientists have shown that inoculating
the anthers of wheat plants with these bacteria (dubbed
"CMB," for "choline-metabolizing bacteria")
helps keep scab to a minimum on the plants.
How does it work? The scientists aren't 100 percent sure,
but they have a pretty good theory. The idea is that the
scab fungus relies on choline — remember, choline
is also produced by the wheat plant's anthers — to
tip it off that it's time to form a specialized tube that
pokes into the wheat anther tissues.
But if the flower-dwelling bacteria have already made themselves
at home on the wheat plant, they may start gobbling up the
wheat-anther choline as soon as it appears. That means there's
less choline lying around to cue the scab fungus that it's
time to attack the wheat anthers.
To test this theory, the scientists isolated 123 CMB from
wheat field soils and put them through their paces in the
greenhouse. From those 123, they chose 10 strains that looked
promising for suppressing scab under field conditions.
Next, they sprayed formulations of the flower bacteria onto
plots of two commercial wheat cultivars just as the wheat
plants were flowering. While the flower bacteria didn't
completely stop the scab in its tracks, they did reduce
the severity of the scab by as much as 63 percent. That's
not far behind the level of control provided by the one-and-only
fungicide that can currently be considered for use against
scab in wheat.
The scientists aren't saying these flower bacteria can beat
back scab all by themselves. Instead, they're envisioning
teaming them with other scab-fighting microbes, including
yeasts and other bacteria that the scientists previously
identified and patented.
Still, the choline-eaters could play a special role because
they have a different way of stymying the scab fungus, compared
with the other microbial weapons. Meanwhile, the scientists
are collaborating with a company that's hoping to develop
one of those yeasts as a biopesticide.
This "bug versus bug" action could add up to a
little more protection for wheat growers against scab outbreaks,
which have already caused billions of dollars in losses
in U.S. wheat and barley. And that extra protection could
translate to more affordable groceries for all of us!
|
Select a Florist
