Transgenic Populus hybrid expresses a wound-inducible potato proteinase inhibitor II - CAT gene fusion

A hybrid poplar clone has been transformed with a previously constructed wound-inducible potato proteinase inhibitor (pin2) – chloramphenicol acetyltransferase (CAT) chimeric gene linked to a nopaline synthase (nos) – neomycin phosphotransferase II (NPT II) selectable marker gene. The Populusalba × Populusgrandidentata Hansen clone was transformed by means of leaf cocultivation with Agrobacteriumtumefaciens strain A281 containing a binary vector. Shoots were regenerated and rooted on selective medium containing kanamycin sulfate. Subsequently, plants were established in soil for greenhouse and field growth. NPT II activity from the nos – NPT II selectable marker gene was observed in leaf extracts, thereby confirming expression of the transferred selectable marker gene in poplar. Southern hybridization confirmed the incorporation of a single copy of the pin2–CAT construction into the genome of the transformed hybrid poplars. Northern analysis of transgenic poplar leaves demonstrated that the potato pin2–CAT gene construction also was inducible in this woody dicotyledon. Thus, the wound-inducible promoter from an herbaceous dicot functions in a distinct family of woody dicots.