Although many insect resistance genes have been identified, the number of studies examining their effects in combination using transgenic systems is limited. This study introduced a construct into maize containing the coding sequence for maize ribosome-inactivating protein (MRIP) and wheat germ agglutinin (WGA). 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 MRIP and WGA. There was also some indication that resistance to
Fusarium verticillioides was increased in the transgenic plant leaves. No statistically significant synergism or antagonism occurred between the activities of the two proteins. MRIP and WGA represent compatible class examples of food plant-derived proteins for multigene resistance to insects.
Keywords:
ribosome-inactivating protein; insect resistance; agglutinin; Helicoverpa; Spodoptera