Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2003
Publication Date: 6/18/2003
Citation: Dowd, P.F., Zuo, W.N., Gillikin, J., Johnson, E.T., Boston, R.S. Enhanced resistance to Helicoverpa zea in tobacco expressing an activated form of maize ribosome-inactivating protein. Journal of Agricultural and Food Chemistry 51(12):3568-3574. Interpretive Summary: Insect damage to corn not only causes great direct economic losses but also results in indirect losses associated with the contamination of damaged tissues with ear mold toxins. A gene potentially involved in insect resistance to maize was introduced into tobbaco. The two transformed tobacco lines were significantly more resistant to corn ear worms and cigarette beetles than untransformed lines. This corn gene will be of value in breeding for insect resistance and in the introduction of resistance genes through biotechnology to potentially result in lower corn production costs and healthier corn with reduced ear mold contamination.
Technical Abstract: Progeny of two transgenic tobacco (Nicotiana tabacum L.) lines that expressed an activated form of maize (Zea mays L.) ribosome inactivating protein (RIP), had varying resistance to the insect species tested. R2 plants appeared to segregate for resistance to larvae of the cigarette beetle, Lasioderma serricorne (F.), and the tobacco hornworm, Manduca sexta (L.). Progeny (R3) of the more resistant R2 plants were tested more extensively for insect resistance. Resistance to the corn earworm, Helicoverpa zea (Boddie), was most consistent, with significantly decreased feeding often accompanied by increased mortality and reduced weights of survivors fed on leaf disks of the two transgenic lines compared to the wild type. The amount of damage by H. zea was significantly inversely correlated with levels of RIP. The R3 transgenic plant leaf disks were also often more resistant to feeding by larvae of L. serricorne compared to wild type plants. Although reduced feeding by M. sexta was noted when fed leaf disks from transgenic compared to wild-type plants the first day of exposure, differences were not significant. This information provides further support for maize RIP having a role in resistance to maize feeding insects.