Nav: Home

New Microbial Insecticide As Potent As Bt

June 25, 1998

MADISON - By isolating and characterizing the biochemical properties of a new-found natural insecticide, scientists have taken an important step toward augmenting the sparse armamentarium of biological pest control.

Writing today (Friday, June 26) in the journal Science, a team of scientists from the University of Wisconsin-Madison describe the properties of a family of insecticidal toxins produced by Photorhabdus luminescens, a bacterium that, in nature, infects and kills insects with the help of a tiny worm or nematode.

The toxins produced by Photorhabdus are active against a wide range of insects and are at least as potent as the insect-killing poisons produced by Bacillus thuringiensis or Bt, the reigning king of natural insecticides, according to Richard ffrench-Constant, a UW-Madison professor of toxicology in the department of entomology and the principal author of the new study.

"These new toxins are highly efficient killers of insects and they hold for the future the same promise first revealed in Bt more than 30 years ago," said ffrench-Constant.

Widely used for decades in the home, in forests and on farms, Bt is also a bacterium and is considered to be a safe, effective and environmentally benign weapon in the war on insect pests. Moreover, in the last few years the genes that govern the production of the Bt toxin have been moved from the bacterium into crop plants, which this year account for 20 percent of the U.S. cotton crop and nearly 10 million acres of transgenic corn, mostly in the Midwest.

As a form of biological pest control, Bt is the only bacterium from which widespread commercial insecticidal applications have been possible, giving it, in effect, a microbial monopoly on insect control worth hundreds of millions of dollars.

But the development of new, naturally occurring insecticides has taken on new urgency in recent years as resistance to Bt has been reported in some populations of insect pests.

"Potential resistance to Bt is now a big issue," said ffrench-Constant. "Developing new biological agents for the control of insect pests is therefore essential."

Photorhabdus, ffrench-Constant suggests, may become an important alternative to Bt, or could be deployed in concert with Bt to prolong the effective life of both biological insecticides by delaying the evolution of resistant strains of insect pests. He described the deployment of Bt transgenic crops as the biggest experiment in natural selection for insecticide resistance since the introduction of chemical pesticides 50 years ago.

"What we have with Photorhabdus and other bacteria is a natural source, almost an infinite variety" of toxic molecules, says ffrench-Constant. "We can't afford to hook ourselves to a single bacterium or a single toxin."

In nature, Photorhabdus bacteria live inside the guts of nematodes that invade insects. Once inside an insect host, the bacteria are released from the nematode, kill the insect, and set up rounds of bacterial and nematode reproduction that turns the insect into a "protein soup," food for large numbers of nematodes.

Moreover, the insect corpses left behind glow in the dark as the microbe produces luminescent proteins in addition to potent insecticides.

Previous studies have shown that, in concentrated doses, the toxin can be used as a spray or fed directly to insects. The greatest potential application, however, lies in transferring the toxin-producing genes from the bacteria to crop plants.

The incentive to confer crop plants with their own insecticides is huge. Farmers now spend more than $575 million annually on chemical pesticides to protect corn alone.

In addition to ffrench-Constant, co-authors of the Wisconsin study include David Bowen, Thomas A. Rocheleau, Michael Blackburn, Olga Andreev, Elena Golubeva and Rohit Bhartia.
-end-
Terry Devitt, (608) 262-8282, trdevitt@facstaff.wisc.edu
-end-


University of Wisconsin-Madison

Related Bacteria Articles:

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.
Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.
Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.
Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.
Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.
How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.
The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?
Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.
Bacteria uses viral weapon against other bacteria
Bacterial cells use both a virus -- traditionally thought to be an enemy -- and a prehistoric viral protein to kill other bacteria that competes with it for food according to an international team of researchers who believe this has potential implications for future infectious disease treatment.
Drug diversity in bacteria
Bacteria produce a cocktail of various bioactive natural products in order to survive in hostile environments with competing (micro)organisms.
More Bacteria News and Bacteria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at Radiolab.org/donate.