Cry34Ab1 is one member of a binary ''

Bacillus thuringiensis ''Bacillus thuringiensis'' (or Bt) is a gram-positive, soil-dwelling bacterium, the most commonly used biological pesticide worldwide. ''B. thuringiensis'' also occurs naturally in the gut of caterpillars of various types of moths and butterflie ...

'' (Bt) crystal protein set isolated from Bt strain PS149B1. The protein exists as a 14 kDa aegerolysin that, in presence of Cry35Ab1, exhibits insecticidal activity towards

Western Corn Rootworm The Western corn rootworm, ''Diabrotica virgifera virgifera'', is one of the most devastating corn rootworm species in North America, especially in the midwestern corn-growing areas such as Iowa. A related species, the Northern corn rootworm, ...

. The protein has been transformed into

maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...

plants under the commercialized events 4114 (DP-ØØ4114-3) by

Pioneer Hi-Bred Pioneer Hi-Bred International, Inc. is a U.S.-based producer of seeds for agriculture. They are a major producer of genetically modified organisms (GMOs), including genetically modified crops with insect and herbicide resistance. As of 2019, Pi ...

and 59122 (DAS-59122-7) by

Dow AgroSciences Dow AgroSciences LLC was a wholly owned subsidiary of the Dow Chemical Company specializing in not only agricultural chemicals such as pesticides, but also seeds and biotechnology solutions. The company was based in Indianapolis, Indiana, in ...

. These events have, in turn, been bred into multiple trait stacks in additional products. Cry34/35Ab1 binary toxins bind to the insect's

brush border A brush border (striated border or brush border membrane) is the microvilli-covered surface of simple cuboidal and simple columnar epithelium found in different parts of the body. Microvilli are approximately 100 nanometers in diameter and the ...

membrane vesicles (BBMVs) of cells in the epithelial lining of midgut, where they form pores; this leads to

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...

and, eventually, the insect's death. The Cry35Ab1 (45 kDa) protein does not convey specificity in the absence of Cry34Ab1, indicating that the smaller 14 kDa Cry34Ab1 protein is critical for BBMV binding and recruitment of Cry35Ab1 to induce insecticidal effect. Cry34Ab1 is unrelated to Bt delta-endotoxins. It is an aegerolysin () composed of two beta sheets in a beta-sandwich structure; the total protein is composed of 117 amino acid residues and contains a hydrophobic core. Its family placement shows that interaction with cell membranes is consistent with its role in the binary Cry34Ab1/Cry35Ab1 toxin complex. The partner toxin, Cry35Ab1, is a prototypical member of its own group (). Its structure is similar to that of

aerolysin In molecular biology, aerolysin is a cytolytic pore-forming toxin exported by ''Aeromonas hydrophila'', a Gram-negative bacterium associated with diarrhoeal diseases and deep wound infections. The mature toxin binds to eukaryotic cells and aggrega ...

, Cry45Aa1, and Cry46Aa1.

References

Bacterial toxins {{toxins