Double Trouble: How Corn Borers Dodge Bt Proteins

The Asian corn borer is a serious threat to corn crops in Asia. This pest has a knack for developing resistance to genetically modified crops. These crops produce insecticidal proteins from a bacterium called Bacillus thuringiensis, or Bt for short. To stay ahead of these pests, scientists need to understand how resistance works. This understanding can help in monitoring and managing the pests better. The Asian corn borer is closely related to the European corn borer. Both are major pests in their respective regions. Resistance to Bt proteins in various moth species, including these corn borers, is linked to mutations in specific larval midgut proteins. These proteins are cadherin and two ATP-binding cassette proteins, ABCC2 and ABCC3. Researchers used CRISPR/Cas9 to create mutations in these proteins. They studied how these mutations affect resistance to two Bt proteins, Cry1Ab and Cry1Fa. The findings were surprising. Cry1Ab can kill larvae through two different paths. One path involves ABCC2, and the other requires both cadherin and ABCC3. In contrast, Cry1Fa relies solely on the ABCC2 path. This discovery is crucial. It shows that Cry1Ab has a backup plan. If one path is blocked, it can still kill the larvae through another. This redundancy could help maintain the effectiveness of Cry1Ab against the Asian corn borer. It might also be a common strategy in nature to delay resistance. However, this is not the end of the story. The study also found that the responses to Cry1Ab and Cry1Fa varied when tested in modified cells and oocytes. This suggests that the story is more complex. Further research is needed to fully understand these interactions. Only then can scientists develop better strategies to combat pest resistance. The battle against pest resistance is ongoing. Every new finding brings hope and challenges. Understanding the genetic basis of resistance is key. It can help in developing more effective and sustainable pest management strategies. This way, crops can be protected, and food security can be ensured.