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We describe the establishment of an activation tagging system in poplar based upon the maize Ac/Ds transposable element system. Transgenic poplar plants were obtained carrying either one or two of the above mentioned constructs Following induction of the GIP promoter only a weak transposase signal could be detected in RT- PCR experiments. Mobility of the ATDs activation construct could not be confirmed in the GIP system. An Activation Tagging experiment was initiated using eight different double transgenic lines. A few putative variants could be obtained revealing deficiency in chlorophyll content. Single transgenic aspen lines carrying HSP- transposase have been produced. Following transformation with HSP-transposase a chimerical transgenic line was obtained revealing white and green plants. Following activation tagging experiment a HSP-transposase/ATDs-rolC double transgenic line, one somaclonal variation line was obtained revealing white plants.

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