Potato transformation to combine natural and engineered resistance for controlling tuber moth

Potato tuber moth (Phthorimaea operculella Zeller) is a highly destructive pest of the cultivated potato (Solanum tuberosum L.) in the tropics and subtropics and causes significant damage to both leaves and tubers. Development of host plant resistance is a central component of an integrated pest management (IPM) program for potato tuber moth. The purpose of this research was to augment natural resistance by transforming potato with a codon-modified CryV-Bt gene using Agrobacterium-mediated techniques. 'Lemhi Russet' potato and two clones with different host plant resistance mechanisms, USDA8380-1 (leaf leptines) and L235-4 (glandular trichomes), were transformed with the CryV-Bt gene. Gene integration of regenerated plants was confirmed by polymerase chain reactions and Southern analyses; gene transcription was evaluated by northern analyses. Detached leaf bioassays showed that high levels of Bt expression occurred in the CryV-Bt transgenic lines ('Lemhi Russet' and L235-4), providing up to 96% control of potato tuber moth larvae, compared with 3% and 54% control in L235-4 and USDA8380-1, respectively. These transgenic lines can be used for breeding purposes to develop cultivars for (and eventual introduction into) IPM systems.