Transgenic plants expressing (at 0.05–0.1% w/w of the total soluble protein) an insecticidal toxin gene from Bacillus thuringiensis (Bt) have been shown to be protected selectively against herbivorous larvae of lepidopteran, coleopteran, or dipteran pests. The main crops transgenic with Bt are corn, cotton, canola, potato, and tomato. In many cases the cry1Ac gene from B. thuringiensis subsp. kurstaki affords resistance to attack by the European corn borer (ECB). Some 183 million acres of Bt transgenic corn and cotton have been planted between 1996 and 2004 in the United States, representing 27% of total GE crop acreage. In the European community, transgenic maize and cotton transformed with Bt genes are now approved for cultivation and use.

Mammalian Antibodies

In 1989 the first report of successful transformation of tobacco plants with complementary DNAs (cDNAs) to mouse immunoglobulin heavy (H) or light (L) chains appeared. More remarkable still was the demonstration that by cross-pollinating these transgenic plants, some of the progeny expressed both H and L chains, assembled functional mouse monoclonal antibody, and exported it from the plant cell in the same way that mouse immune system cells handle these proteins. Since then, it has become relatively straightforward to create transgenic plants that express a functional mouse monoclonal antibody to any specified epitope on a pathogen simply by taking H- and L-mRNAs from a particular hybridoma cell culture, using polymerase chain reaction primers to create cDNAs and transforming plants with these constructs.