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The present study was performed to express stacked insecticidal genes in potato cv. Lady Olympia and Agria to encode resistance against Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say). Bacillus thuringiensis (Bt) gene (cry3A), synthetic hybrid (SN-19) and plant proteinase inhibitor Oryza cystatin II (OCII) cloned in pCAMBIA1301 binary vector in two different combinations as of DS-1 (cry3A + SN-19 genes) and DS-2 (OCII + SN-19 genes) constructs and further transformed to two potato cultivars using Agrobacterium-mediated transformation. All molecular analyses confirmed gene integration and expression in a total of 27 primary transformants in both Agria and Lady Olympia. Insecticidal effects of T0 progeny transgenic potato plants were tested against CPB under laboratory conditions. Transgenic plants of Agria and Lady Olympia transformed with DS-1 and DS-2 constructs caused 100% mortality to all larval stages and adults of CPB. However, 100% mortality of tested insects took a longer time in the adult stage (10–14 days) compared to larval stages (2–6 days). Foliage consumption by L2-L4 larval stages and adults of CPB was significantly reduced in Agria and Lady Olympia plants transformed with DS-1 and DS-2 constructs, as compared to their control plants. Lower foliage consumption of transgenic plants by L1 larval stages was also observed, but the reduction was only statistically significant for some of the tested plants. These promising results indicate that the transgenic potato plants exhibit a high potential in controlling CPB population and are a useful tool in the management of imidacloprid-resistant CPB. [ABSTRACT FROM AUTHOR]

We have tested the CinH- RS2 and ParA- MRS site-specific deletion systems in tomato ( Solanum lycopersicum L.). The ParA- MRS system is derived from the broad-host-range plasmid RK2, where the 222 aa ParA recombinase recognizes a 133 bp multimer resolution site ( MRS). The CinH- RS2 system is derived from Acinetobacter plasmids pKLH2 and pKLH204, where the 188 amino acid CinH recombinase recognizes a 113-bp recombination site known as RS2. In this study, target lines containing a DNA segment flanked by recombination sites were crossed to recombinase-expressing lines producing CinH or ParA recombinase. CinH-mediated recombination of RS2 substrates was detected in 2 of 3 F plants that harbor both the target and recombinase loci. On the other hand, recombination mediated by ParA was not detected among F plants, but was found among 13 of 47 F plants. These data show that both systems can mediate site-specific DNA deletion in the tomato genome, and, upon further refinement, can provide additional molecular tools for tomato improvement through precise genome manipulation. As the target construct also contains additional recombination sites for site-specific integration by other recombination systems, these tomato lines could be used for future testing of gene stacking through site-specific integration. [ABSTRACT FROM AUTHOR]