Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 10, 2012
Publication Date: December 1, 2012
Citation: Dowd, P.F., Johnson, E.T., Price, N.P. 2012. Enhanced pest resistance of maize leaves expressing monocot crop plant derived ribosome inactivating protein and agglutinin. Journal of Agricultural and Food Chemistry. 60(1):10768-10775. Interpretive Summary: Insects cause billions of dollars of damage to corn and facilitate the entry of ear molds that produce toxins. The most effective plant gene combinations for promoting resistance to these insect pests is unknown. A corn and a wheat derived gene, representing two different classes of corn resistance genes, were introduced and expressed continually in corn leaves. Leaves that expressed the higher levels of these gene products had less damage by the insect and fungal corn pests examined that those that expressed lower levels. Activity of one resistance protein did not appear to interfere with the activity of the other. Development of corn hybrids that express sufficient levels of these gene classes should lead to enhanced economical production for growers, and better quality corn and corn products for processors, exporters and consumers.
Technical Abstract: Although many insect resistance genes have been identified, the number of studies examining their effects in combination using transgenic systems is limited. We introduced a construct into maize containing the coding sequence for maize ribosome inactivating protein (MRIP), wheat germ agglutinin (WGA), and tobacco hornworm chitinase (THWC). Although THWC could not be detected, many transformants produced both the MRIP and WGA in leaves. Mature leaves expressing higher levels of these two proteins were more resistant to feeding by first instar larvae of fall armyworms (Spodoptera frugiperda) and corn earworms (Helicoverpa zea), and the level of resistance was correlated with levels of maize RIP and WGA. There was also some indication that resistance to Fusarium verticillioides was increased in the transgenic plant leaves. As no antagonism was noted for the two proteins in combination, MRIP and WGA represent compatible class examples of food plant-derived proteins for multigene resistance to insects.