The Return of Flower Power
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!
"Everybody's
Science" is written by Sandy Miller Hays, Director of Information for
the Agricultural Research Service, the chief scientific research agency
of the U.S. Department of Agriculture. Hays is a native of Fort Smith,
Ark. From the late 1970s until early 1988, Hays was a reporter, editor
and columnist at the Arkansas Democrat (now the Arkansas Democrat-Gazette),
a Little Rock-based daily newspaper. She joined the ARS Information
Staff in 1988, and became Director of Information in April 1998.
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.)
Typical premature whitening of a wheat head infected with the fungus that causes Fusarium head blight. (Photo by Crop Bioprotection Research)
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!
The Agricultural Research Service is the chief in-house scientific
research agency of the U.S. Department of Agriculture. You can read
more about ARS discoveries at http://www.ars.usda.gov/news/.
About the author
"Everybody's
Science" is written by Sandy Miller Hays, Director of Information for
the Agricultural Research Service, the chief scientific research agency
of the U.S. Department of Agriculture. Hays is a native of Fort Smith,
Ark. From the late 1970s until early 1988, Hays was a reporter, editor
and columnist at the Arkansas Democrat (now the Arkansas Democrat-Gazette),
a Little Rock-based daily newspaper. She joined the ARS Information
Staff in 1988, and became Director of Information in April 1998.