Navigation Links
New bacteria toxins against resistant insect pests
Date:10/19/2011

This release is available in German.

Toxins from Bacillus thuringiensis bacteria (Bt toxins) are used in organic and conventional farming to manage pest insects. Sprayed as pesticides or produced in genetically modified plants, Bt toxins, used in pest control since 1938, minimize herbivory in crops, such as vegetables, maize or cotton. Since 1996, Bt producing transgenic crops have been grown, which successfully control pests like the European corn borer, the tobacco budworm, the Western corn rootworm, and the cotton bollworm. Over the years, Bt resistant insects have emerged in organic and conventional farming. Scientists have therefore modified the molecular structure of two Bt toxins, Cry1Ab and Cry1Ac, in order to overcome resistance. The novel toxins, Cry1AbMod and Cry1AcMod, are effective against five resistant insect species, such as the diamondback moth, the cotton bollworm, and the European corn borer. Cry1AbMod and Cry1AcMod can be used alone or in combination with other Bt toxins for plant protection.

New insights into the mechanisms of action of Cry1Ab and Cry1Ac served as the basis for development of the modified Bt toxins. The primary question had been why the Cry proteins, which naturally occur in B. thuringiensis, have such a resoundingly toxic effect on many different herbivorous insects. Researchers had previously found a protein in the caterpillars' midgut that binds Bt toxins with fateful consequences for the insects, because binding the toxins causes the gut cells to die. This protein is one of the many types of cadherin proteins in the cell. Mutations of a specific cadherin can make the caterpillars resistant against the toxins.

"When we studied the new Bt toxins in twelve resistant and non-resistant strains of five major pest species, the results of our experiments were encouraging but surprising. The new toxins are also effective against strains whose Bt resistance is not based on cadherin mutations," says David G. Heckel, director of the Department of Entomology at the Max Planck Institute for Chemical Ecology in Jena, Germany, and co-author of the study. Especially interesting was the finding that the new toxins were specifically effective against a super-resistant strain of tobacco budworm carrying both the cadherin mutation and another mutation affecting an ABC transporter which was discovered by the Max Planck researchers last year.

Particularly striking was the effect of Cry1AbMod and Cry1AcMod on a Bt resistant corn borer and a resistant diamondback moth strain that was 350 times stronger compared to that of the natural toxins. On the other hand, the new toxins had only a weak effect on some strains whose Bt resistance is due to a mutated cadherin.

If both novel Bt toxins prove to be useful in agriculture, they can be used in combination with different Bt toxins to guarantee a reliable effect on herbivorous pests. Biologists also agree that measures to reduce the occurrence of resistant insect pests must be strictly adhered to and that farmers should be informed in detail. Such measures would mainly include the use of different pesticides, crop rotation, and simultaneous sowing of non-Bt plants in fields, where transgenic Bt varieties are grown.


'/>"/>

Contact: David G. Heckel
heckel@ice.mpg.de
49-364-157-1500
Max-Planck-Gesellschaft
Source:Eurekalert  

Related biology news :

1. Bacteria forge nitrogen from nitric oxide
2. University of California Santa Barbara study reveals how gas, temperature controlled bacterial response to Deepwater Horizon spill
3. Study: Residential washers may not kill hospital-acquired bacteria
4. Bionic bacteria may help fight disease and global warming
5. UTHealth student earns fellowships to research major source of bacterial infections
6. Unknown ocean bacteria create entirely new theories
7. Up from the depths: How bacteria capture carbon in the twilight zone
8. Scientists reengineer antibiotic to overcome dangerous antibiotic-resistant bacteria
9. New CU-Boulder study reveals bacteria from dog feces in outdoor air of urbanized air
10. U of Minnesota researchers discover a natural food preservative that kills food-borne bacteria
11. University of Houston professor co-authors PNAS paper on how bacteria move
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
New bacteria toxins against resistant insect pests
(Date:11/24/2016)... Calif. , Nov. 23, 2016 Cercacor ... endurance athletes and their trainers non-invasively measure ... Index, Pulse Rate, and Respiration Rate in approximately 30 ... enables users easy and immediate access to key data ... part of a training regimen. Hemoglobin ...
(Date:11/22/2016)... Nov. 22, 2016   MedNet Solutions , an ... spectrum of clinical research, is pleased to announce that ... Healthcare and Life Sciences Awards as "Most Outstanding ... an unprecedented year of recognition and growth for MedNet, ... 15 years. iMedNet ™ , ...
(Date:11/19/2016)... DALLAS , Nov. 18, 2016 Securus ... technology solutions for public safety, investigation, corrections and monitoring, ... a smaller competitor, ICSolutions, to have an independent technology ... set, the most modern high tech/sophisticated telephone calling platform, ... tell customers that they do most of what we ...
Breaking Biology News(10 mins):
(Date:12/7/2016)... 2016 /PRNewswire/ - Zenith Capital Corp. ("Zenith" or the "Company") announces ... at the Company,s Annual and Special Meeting. ... place on Thursday, December 15, 2016 at Mount ... EC1040), 4825 Mount Royal Gate SW, Calgary, Alberta ... meeting and management information circular, containing the matters to be ...
(Date:12/7/2016)... , Dec. 7, 2016  Biocom, the association for ... the statement below following passage of 21 st Century ... on November 30 by a 392-26 vote and in the ... may be attributed to Joe Panetta , president & ... that will give hope to millions of patients around the ...
(Date:12/7/2016)... 7, 2016  Vyriad Inc. announced today the appointment ... Board of Directors. "We are delighted to ... business and develop our oncolytic viruses as the next ... Stephen Russell , MD, PhD, CEO of Vyriad. "Al ... vision and passion for making a difference for cancer ...
(Date:12/7/2016)... -- Muse bio, a privately-held company leading the development of ... Kevin Ness has been appointed Chief Executive Officer ... Kevin succeeds Muse bio,s founding CEO Ryan ... as well as remains Slade Professor, Chemical and Biological ... the RAS Energy Institute at the University of Colorado, ...
Breaking Biology Technology: