<p style="text-align: justify;">CPB-resistant potato lines BT6, BT10, BT12, BT16, BT17, BT18, and BT23 were produced by <i>Agrobacterium</i>-mediated transformation of potato cultivar &#39;Russet Burbank&#39;. The transfer-DNA (T-DNA) region of a &quot;disarmed&quot; form of the bacterial tumour inducing (Ti) plasmid was modified to contain genes encoding Cry3A delta-endotoxin and NPTII. As a matter of course, Ti plasmids used for plant transformation are &quot;disarmed&quot; such that they do not contain the virulence genes (<i>vir</i>A) that are normally associated with the pathogenicity and disease-causing properties of <i>A. tumefaciens</i>.</p>

<p style="text-align: justify;">A 5&#39;-truncated copy of the <i>cry3A</i> gene, obtained from <i>B. thuringiensis</i>, ssp. tenebrionis (Btt), was modified by site-directed mutagenesis to enhance expression by generating plant-preferred codons. These modifications in nucleotide sequence did not alter the expected amino acid sequence of the Cry3A protein. Expression of the <i>cry3A</i> gene was under the regulatory control of the 35S promoter from cauliflower mosaic virus (CaMV) with a duplicated enhancer region and the 3&#39; nontranslated termination region of a pea ribulose-1,5-bisphosphate carboxylase, small subunit (rbcS) gene. Expression of NPTII, encoded by the <i>neo</i> gene, was regulated by the CaMV 35S promoter and termination sequences from the nopaline synthase (<i>nos</i>) gene from <i>A. tumefaciens</i>.</p>
