Cry6Aa

Crystal structure of Cry6Aa toxin

Cry6Aa is a crystal protein produced by the bacterium Bacillus thuringiensis (Bt). This protein is part of a larger family of Cry proteins that are known for their insecticidal properties. Unlike many other Cry proteins that target Lepidoptera (moths and butterflies) or Coleoptera (beetles), Cry6Aa is unique in its ability to target nematodes.

Structure and Function

Cry6Aa is a delta endotoxin that forms crystalline inclusions during the sporulation phase of Bacillus thuringiensis. Upon ingestion by susceptible nematodes, the protein is solubilized and activated in the alkaline environment of the nematode gut. The activated toxin then binds to specific receptors on the gut cells, leading to cell lysis and death of the nematode.

Mode of Action

The mode of action of Cry6Aa involves several steps:

1. Ingestion by the nematode.
2. Solubilization in the gut.
3. Activation by gut proteases.
4. Binding to specific receptors on the gut epithelial cells.
5. Formation of pores in the gut cell membranes.
6. Cell lysis and death of the nematode.

Applications

Cry6Aa has potential applications in agriculture as a biological control agent against nematode pests. Nematodes are a significant problem in many crops, causing substantial yield losses. The use of Cry6Aa-expressing Bt strains or transgenic plants could provide an environmentally friendly alternative to chemical nematicides.

Research and Development

Ongoing research is focused on understanding the detailed mechanism of action of Cry6Aa, identifying the specific receptors in nematodes, and developing transgenic crops that express Cry6Aa for enhanced nematode resistance.

Related Pages

• Bacillus thuringiensis
• Cry proteins
• Nematode
• Biological pest control
• Transgenic plants