Resistance to insects in transgenic Solanum plants expressing a peroxidase gene from horseradish

To engineer insect-resistant Solanum plants, a peroxidase C2 gene (prxC2) from horseradish was introduced into Solanum integrifolium Poir. cv. Hiranasu. We produced 77 transgenic Hiranasu plants. Peroxidase expression was confirmed at the transcriptional and translational levels by northern blot analysis and by measuring peroxidase activity, respectively. Feeding test results show that transformant no. 180 is more resistant to corn earworm (Heliothis armigera) and common cutworm (Spodoptera litura) than the wild-type plants. We also found a correlation between insect resistance and lignin content in the transgenic plants. In particular, the lignin content of transformant no. 180 was 30% higher than that of wild-type plants. These results further confirm that peroxidase is functionally expressed in transgenic plants and suggest that the increased lignin content is a basis for the insect resistance in transgenic Hiranasu plants.