<p>The NewLeaf-Plus&trade; potato (Solanum tuberosum) lines RBMT21-129, RBMT21-350 and RBMT-22-082 were developed through a specific genetic modification of cultivar Russet Burbank to be CPB (Leptinotarsa decemlineata Say.) resistant and to resist infection by PLRV. The novel lines produce a version of the insecticidal protein, CryIIIA, derived from Bacillus thuringiensis, and the DNA sequences corresponding to open reading frames 1 (ORF-1) and 2 (ORF-2) from PLRV. Delta-endotoxins, such as the CryIIIA protein expressed in Russet Burbank NewLeaf-Plus&trade; potatoes, act by selectively binding to specific receptors localized on the brush border midgut epithelium of susceptible insect species. Following binding, cation-specific pores are formed that disrupt midgut ion flow and thereby cause paralysis and death. CryIIIA and related endotoxins are insecticidal only to lepidopteran or coleopteran insects and their specificity of action is directly attributable to the presence of specific receptors in the target insects. There are no receptors for delta-endotoxins of B. thuringiensis on the surface of mammalian intestinal cells, therefore, livestock animals and humans are not susceptible to these proteins. PLRV is a spherical RNA virus belonging to the luteovirus group and is transmitted primarily by the green peach aphid (Myzus persicae). This virus has a worldwide distribution and commonly infects potato causing serious disease and economic loss. The introduced viral sequences do not result in the formation of any infectious particles, nor does their expression result in any disease pathology. The genetically modified potato cultivars exhibit the trait of resistance to infection and subsequent disease caused by PLRV through an incompletely understood process which may involve silencing of viral gene translation, which has been termed &ldquo;replicase-mediated resistance&rdquo;. The transgenic Russet Burbank potato lines RBMT21-129, RBMT21-350 and RBMT22-082 were created through two separate Agrobacterium-mediated transformation events in which the transfer DNA (T-DNA) contained the genes encoding the CryIIIA protein from B. thuringiensis subsp. tenebrionis and the ORF-1 and ORF-2 regions from PLRV. These two ORFs encode the putative viral helicase and replicase domains that are required for viral RNA synthesis. In addition, the T-DNA contained sequences encoding the enzymes neomycin phosphotransferase II (NPTII) or 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). The respective expression of either NPTII or EPSPS activity in RBMT21 and RBMT22 transformation events was used as a selectable trait for screening transformed plants for the presence of the cryIIIA and PLRV replicase genes. There was no incorporation of plant translatable plasmid DNA sequences outside of the T-DNA region and stable inheritance of the novel traits was demonstrated over multiple generations of vegetative propagation. The constitutive expression of CryIIIA protein was demonstrated in each of the transgenic NewLeaf-Plus&trade; Russet Burbank cultivars at levels comparable with previously approved NewLeaf&trade; potato cultivars. The production of viral replicase protein in RBMT21-129, RBMT21-350 and RBMT22-082 was undetectable in either leaf or tuber tissue, and is, therefore, likely to be less than for plants naturally infected with PLRV. The level of expression of NPTII or CP4 EPSPS in all plant tissues from RBMT21- 129 or 350 and RBMT22-082, respectively, was comparable to the amounts measured in previously approved novel plants expressing either of these proteins. The presence of NPTII protein has been judged to be insignificant with respect to any human health risk due to exposure. Solanine and chaconine are the principal glycoalkaloids commonly found in potato tubers. The concentration of total glycoalkaloids (TGA) in NewLeaf-Plus&trade; Russet Burbank tubers ranged between 4.3-17.1 mg/100g fresh weight tissue, with a mean value of 6.7 mg/100g fresh weight tissue. This is comparable to the TGA range of 2.5-16.1 mg/100g fresh weight tissue that was previously measured in tubers from commercial non-transgenic cultivars of Atlantic, Gemchip, Norchip and Russet Burbank. In each case, the TGA concentration in transgenic tubers was below the administrative guideline of 20 mg/100g fresh weight that has previously been established for TGA in potato. Other than resistance to CPB and infection by PLRV, the disease, pest and other agronomic characteristics of the NewLeaf-Plus&trade; Russet Burbank lines were comparable to the non-transgenic Russet Burbank cultivar.</p><br>