Wound expression of a potato proteinase inhibitor II gene in transgenic tobacco plants.

A potato proteinase inhibitor II gene was transferred into tobacco plants using Agrobacterium/Ti-plasmid-mediated gene transfer techniques. Whereas no or little expression of the proteinase inhibitor II gene could be detected in non-wounded leaves, high levels of proteinase inhibitor II mRNA were detected in leaves of several transgenic tobacco plants after mechanical wounding as well as after treatment of detached leaves with oligosaccharides. Wounding of a leaf also led to a systemic induction in non-wounded leaves as well as non-wounded stem, and roots. RNA-protection experiments showed that the transcription of the proteinase inhibitor gene in transgenic tobacco plants was initiated at the same nucleotide as that of the original gene. These observations demonstrate that although no proteinase inhibitor II homologous gene can be detected in tobacco, this plant nevertheless has the capacity to regulate the expression of the potato gene in the same complex manner as in the case of potato.