engleski

Synthetic Mini-Inhibitors Sharing CMTI-I-CSTI-IIb Skeleton Confer Insect Resistance to Transgenic Tobacco and Potato Plants

With the purpose to obtain plants resistant to harmful insects, 12 different synthetic mini-inhibitors sharing CMTI-I-CSTI-IIb skeleton were expressed in tobacco and potato. Genes were designed according to amino acid sequences of Cucurbita maxima trypsin inhibitor I (CMTI-I) and Cucumis sativus trypsin inhibitor-IIb (CSTI-IIb). At the reactive site of mini-inhibitors (P1-P1') amino acid characteristic for different trypsin inhibitors were combined. Genes were synthesised using Klenow fragment of DNA polymerase I. Agrobacterium tumefaciens EHA 105 using recombinant pBI 121 vectors were used for transformation. Altogether more than 270 tobacco and more than 100 potato plants transformed with one or the other construct were regenerated. Stable integration of transgenes in putative transgenic plants was determined by PCR analysis using genomic DNA and primers that anneal to promoter and terminator region. The first step of mini-gene expression in transgenic plant was revealed by RT-PCR analysis. cDNA amplified from mRNA of synthetic genes showed the expected length of 105 bp. In entomological tests where larvae were fed with leaves, influence of transgenic T0 tobacco and potato, as well as non-transgenic control plants on retardation of larval growth of S. littoralis was examined. Results of entomological tests showed that it is possible to express mini-inhibitors in plants at level that significantly reduces S. littoralis larval growth.

transgenic plants; insect resistance; proteinase inhibitors

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