Development and Evaluation of Codon-modified cryV Constructs in Cultivated Potato(Solanum tuberosum L.) for Control of Potato Tuber Moth

A cryV gene,specifically toxic to Lepidoptera and Coleoptera,was incorporated into binary vectors with different promoters and the presence or absence of the β-glucuronidase(gus) reporter gene.These constructs were integrated into potato cv.Spunta by Agrobacterium tumefaciens-mediated transformation.Highest expression of cryV gene,determined by mRNA levels and insect mortality,was obtained using the CaMV 35S promoter without the gus gene configuration.Detached leaf and tuber bioassays showed a mortality rate of up to 83% and 100%,respectively,for potato tuber moth(Phthorimaea operculella Zeller) in the transgenic lines.Our results demonstrated that the presence of the gus gene negatively affects the expression level of the cryV gene.Bt expression was also facilitated by using the(ocs)3 mas super promoter,whereas the Bt expression regulated by the patatin promoter(tuber-specific) was too low to have any effect upon the mortality of potato tuber moth.These results represent significant improvement in the level of host plant resistance for the control of potato tuber moth via Bt transgenes.