Transgenic Potato Lines Expressing cry1Ba1 or cry1Ca5 Genes are Resistant to Potato Tuber Moth

摘要

Modified cry1Ca5 and cry1Ba1 genes, under the transcriptional control of a CaMV 35S promoter, were individually transferred into potato (Solanum tuberosum L.) cv. Iwa using Agrobacterium-mediated transformation. Thirty-six and thirty-eight independently derived cry1Ca5- and cry1Ba1-transgenic plants were regenerated respectively. Multiplex-PCR confirmed the presence of the nptII selectable marker gene and the specific cry gene in all regenerated lines. In greenhouse experiments, approximately 90% of each transgenic population produced phenotypically normal plants. More than 90% of the cry1Ca5-transgenic lines gave 100% larval mortality of potato tuber moth (PTM), Phthorimaea operculella (Zeller), on excised greenhouse-grown leaf and tuber bioassays. In contrast, only 40–50% of the cry1Ba1-transgenic lines gave 50 to 100% of larval mortality of PTM using the same bioassays, although all lines except one significantly inhibited larval growth. Southern blot analysis for eight selected cry1Ca5-transgenic lines revealed that they contained 1 to 6 copies of the cry gene. The amount of Cry1C protein, quantified by ELISA, ranged from 0.26 to 8.42 μg per g of leaf tissue and from 0.23 to 1.02 μg per g of tuber tissue. No relationship was apparent between cry1Ca5 gene copy number and amount of Cry protein expressed in leaves and tubers. Southern blot analysis for seven selected cry1Ba1-transgenic lines revealed that they contained 2 to 8 copies of the cry1Ba1 gene. Both the cry1Ca5 and cry1Ba1 genes offer additional sources of resistance that can be deployed with other effective cry genes to control tuber moth in potatoes.