Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Making microscopic worms into a more deadly insecticide

15.01.2010
Microscopic nematode worms can be a potent organic insecticide, killing crop-raiding bugs without harming plants or beneficial insects and without the environmental side effects of chemicals. But when the worms are mass-bred for agricultural purposes, they tend to, as Byron Adams says, “wimp out,” and are not as deadly as their cousins that grow in the wild.

The Brigham Young University biology professor and his students analyzed the genetic changes in lab-raised worms that make them less deadly to bugs. These results will help preserve the talents of what Adams affectionately calls “natural-born killers.” The findings also help us understand how to defeat parasites that harm beneficial plants andanimals and those that cause human disease.

The team reports its results in the new issue of BMC Genomics. Graduate student Bishwo Adhikari is the lead author; two co-authors who were undergraduates at the time are now pursuing Ph.D.s at Caltech and the University of Wisconsin.

How the worms protect crops

When the worm, called H. bacteriophora finds an insect in the soil, it crawls inside and, Adams says, “barfs up” special bacteria that had hitched a ride with the worm. The bacteria quickly kill the insect and spread, and the worm gobbles up the bacteria and reproduces. The bacteria and baby worms eat what’s left of the bug, and then head off together in search of another insect host.

Plants and other insects, such as bees, are spared, and the worms are not toxic to humans. The bacteria are only deadly when introduced inside the insect, not when ingested, and can’t survive in soil or water. So they are only a threat to the insects targeted by the worm, which include the Japanese beetle, many species of weevils, the Colorado potato beetle, cucumber beetles and many others. These pests can wreak havoc on citrus trees, turfgrass, potatoes, and many other crops.

The worms occur naturally in concentrations too small to be effective at eradicating pests. So farmers can purchase bulk quantities of nematodes mass produced in huge fermentation tanks and spread them through irrigation. Producing deadly nematodes by the barrel is the problem.

Lab-grown worms wimp out

Previous research has shown that the worms are less deadly to insects when grown away from their natural habitat. After a few generations, they don’t reproduce or find hosts as well, they have a tougher time tolerating heat and they aren’t as toxic to the bugs they do find.

“We wanted to know the genetic mechanisms that were responsible for these changes, so we did a series of experiments to look at differences in gene expression between the killers and the wimps,” said Adams.

The team examined all of the expressed genes of an inbred line (wimps) of worms and their original parental line (killers). They found differences in the expression of 1,185 genes, including those involved with metabolism, virulence and longevity.

“We show that even very small changes in the relative expression of these genes can produce large changes in wimpiness,” Adams said.

Now scientists can take steps to improve the quality of worms shipped to farmers. But that’s not what has Adams most excited about this work.

Even broader application

“The research also shows that many of the genes involved in the killer/wimp traits in these worms are unique to worms that are nasty parasites of plants, humans and other animal friends,” Adams says.

Some of these genes they identified play fundamental roles in host-parasite interactions, such as virulence and the suppression of host defense systems. That means the products of these genes could be promising targets for pharmaceuticals.

Other interventions could prevent disease by disrupting and altering the functions of these genes – taking what was learned about how the bug-killing nematodes evolved to became less deadly and leading harmful parasites down the same road.

Student contributions serve as launching pad

Two undergrads generated the “wimpy” line of worms for the study, which required experiments to prove that the genetic deterioration came about because of inbreeding and not other potential genetic causes. They are the first authors on another paper about this that has been submitted for publication.

John Chaston, featured here for his work on nematodes in Antarctica, is now a National Science Foundation fellow pursing a Ph.D. at the University of Wisconsin.

Adler Dillman is now at Caltech, studying how genes influence behavior under world renowned worm geneticist Paul Sternberg, also a co-author on the paper. By the time he graduated from BYU, Dillman had presented research at nine scientific conferences.

“Dr. Adams' attitude is unique among undergraduate professors in that he encourages students to study the primary literature and then to approach him with particular studies or questions that they find interesting,” Dillman said. “He then helps you turn that interest into a research program. Working for him was the best thing that happened to me as an undergraduate.”

Other coauthors on the paper are: BYU’s Chin-Yo Lin, Ohio State’s Xiaodong Bai and Parwinder Grewal, Michigan State’s Todd Ciche, the USDA’s David Shapiro-Ilan; and Rutgers’ Anwar Bilgrami and Randy Gaugler.

Michael Smart | EurekAlert!
Further information:
http://www.byu.edu

More articles from Agricultural and Forestry Science:

nachricht New study shows producers where and how to grow cellulosic biofuel crops
17.01.2018 | University of Illinois College of Agricultural, Consumer and Environmental Sciences

nachricht Robotic weeders: to a farm near you?
10.01.2018 | American Society of Agronomy

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>