Submitted to: Transgenic Research
Publication Type: Book / Chapter
Publication Acceptance Date: 5/17/1996
Publication Date: N/A
Technical Abstract: Peroxidases are complex enzymes requiring metal ions and cofactors for activity. Although substrate range is wide, there does appear to be some specificity of different isozymes. Peroxidase functions include hydrogen peroxide catalysis, regulation of endogenous hormone levels, polymerization and crosslinking, and defense against insects and pathogens. Products generated by peroxidases may be cytotoxic, inhibit enzymes, tie up nutrients, and provide mechanical barriers. Whether introduction of peroxidase genes will promote resistance is difficult to predict due to the complexity of reactions involved. Transgenic tobacco overexpressing tobacco anionic peroxidase was more resistant to some insects, depending on the species and size of the insect, and the tissue and maturity of the plant. Similar effects were noted with tomato and tree species expressing the tobacco anionic peroxidase. Because it is a plant-derived resistance trait, and acts by multiple mechanisms, transgenic plants that have enhanced resistance conferred by expression of novel peroxidase genes may have some advantages compared to transgenic plants that have expression conferred by foreign proteins that act as direct toxins.