Submitted to: Transgenic Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2005
Publication Date: 4/10/2006
Citation: Dowd, P.F., Lagrimini, M. 2006. Examination of the biological effects of high anionic peroxidase production in tobacco plants grown under field conditions. I. Insect pest damage. Transgenic Research. 15(2):197-204. Interpretive Summary: Fungal toxins (mycotoxins) in corn cause hundreds of millions of dollars in losses each year. Insects can greatly increase the levels of mycotoxins that can occur in corn by carrying, damaging, and providing entry ways for the causative fungi. A new insect resistance gene has been evaluated in model plant systems in growth chamber and greenhouse studies, but not in field studies. Field tests now indicate this gene produces a protein that results in broad-spectrum resistance to many groups of insects, including both chewing and sucking insect pests. Incorporation of the gene that produces the resistance protein into corn may in the future result in a more resistant crop plant that accumulates lower levels of mycotoxins, thereby providing safer food for animals and people.
Technical Abstract: At least 25 wild-type and high-peroxidase tobacco Nicotiana tabacum L. plants were examined semiweekly over several weeks for pest insect distribution and damage in a two-year field study. Incidence and/or severity of naturally occurring caterpillar damage (dingy cutworm (Feltia ducens Walker), black cutworm (Agrotis ipsilon (Hufnagel), tobacco hornworm (Manduca sexta L.), and false tobacco budworm (= corn earworm Helicoverpa zea (Boddie)) was significantly reduced at several sample dates for high-peroxidase vs. wild-type plants. These results parallel those of prior laboratory studies with caterpillars. The number of adult whiteflies (Trialeurodes vaporariorum (Westwood) per plant was significantly reduced on high-peroxidase compared to wild-type plants on most sample dates in both years. The number of plants with leaves containing >100 aphids (primarily Myzus persicae Sulzer) per leaf on high-peroxidase plants was significantly lower than on wild-type plants after an equivalent invasion period in both years. A significantly higher proportion of aphids were found dead on leaf five of high-peroxidase compared to wild-type plants at most sample dates in both years. These results indicate that high peroxidase plants have resistance to a wide range of insects, implicating this enzyme as a broad-range resistance mechanism.