Superior NewLeaf™ potato

The transgenic potatoes were genetically engineered to be resistant to attack by Colorado potato beetle  by producing their own insecticide. These lines were developed by introducing the cry3A gene.

PV-STBT02

The coding sequence of the Cry3A gene was modified to plant preferred codons. This resulted in changes to 399 of 1791 nucleotides but there were no changes to the resulting amino acid sequence.

Southern blot analysis indicated that they Cry3A and nptII genes and their respective regulatory elements were incorporated into the host genome. No segments from the vector backbone were detected.

The Cry3A protein expressed in these transgenic potato cultivars is identical to that found in nature and in commercial Bt spray formulations. Cry proteins, of which Cry3A is only one, act by selectively binding to specific sites localized on the lining of the midgut of susceptible insect species. Following binding, pores are formed that disrupt midgut ion flow causing gut paralysis and eventual death due to bacterial sepsis. Cry3A is insecticidal only when eaten by the larvae of coleopteran insects such as Colorado potato beetle and its specificity of action is directly attributable to the presence of specific binding sites in the target insects. There are no binding sites for delta-endotoxins of B. thuringiensis on the surface of mammalian intestinal cells, therefore, livestock animals and humans are not susceptible to these proteins.