<p style="text-align: justify;">The transgenic cultivars of &lsquo;Atlantic&rsquo; (ATBT04-6, ATBT04-27, ATBT04-30, ATBT04-31, ATBT04-36) and &lsquo;Superior&rsquo; (SPBT02-5, SPBT02-7) NewLeaf&reg; potatoes were genetically engineered to be resistant to attack by Colorado potato beetle (CPB). These lines were developed by introducing the <i>cry3A</i> gene, isolated from the common soil bacterium <i>Bacillus thuringiensis</i> subspecies <i>tenebrionis</i> (<i>Btt</i>), into the potato genome by <i>Agrobacterium</i>-mediated transformation.</p>

<p style="text-align: justify;">The Cry3A protein expressed in these transgenic potato cultivars is identical to that found in nature and in commercial <i>Bt</i> 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 CPB, elm leaf beetle and yellow mealworm, 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 <i>B. thuringiensis</i> on the surface of mammalian intestinal cells, therefore, livestock animals and humans are not susceptible to these proteins.</p>

<p style="text-align: justify;">An antibiotic resistance marker gene (<i>neo</i>) encoding the enzyme neomycin phosphotransferase II (NPTII), which inactivates aminoglycoside antibiotics such as kanamycin and neomycin, was also introduced into the genome of these plants. This gene was derived from a bacterial transposon (Tn5 transposable element from <i>Escherichia coli</i>) and was included as a selectable marker to identify transformed plants during tissue culture regeneration and multiplication. The expression of the <i>neo</i> gene in these plants has no agronomic significance and the safety of the NPTII enzyme as a food additive was evaluated by the United States Food and Drug Administration in 1994 (US FDA, 1994).</p>
