CLONING AND CHARACTERIZATION OF A CATHEPSIN-D INHIBITOR GENE FROM SOLANUM-TUBEROSUM L

A DNA clone encoding a cathepsin D inhibitor CathInh was isolated from a potato genomic library using a CathInh cDNA as hybridization probe. The amino acid sequence of the coding region is nearly identical with a CathInh cDNA and CathInh proteins previously isolated from a tuber- specific cDNA library and from tubers, respectively. Analysis of GUS a ctivity resulting from expression of chimeric CathInh promoter-GUS gen es in transgenic potato plants revealed expression exclusively confine d to potato tubers. No GUS activity could be detected in any other org an of the transgenic plants either constitutively or after wounding or treatment with abscisic and jasmonic acid (JA). Interestingly, part o f the promoter region of the CathInh gene, essential for GUS activity in tubers, shows striking similarity to promoter regions of tuber-spec ific class I patatin genes.