POTATO (SOLANUM-TUBEROSUM) INVERTASE-ENCODING CDNAS AND THEIR DIFFERENTIAL EXPRESSION

A full-length cDNA clone encoding a potato invertase (Inv) has been is olated. It is highly related (77% nucleotide identity) to a previously characterised potato cDNA clone encoding a putative extracellular Inv . These Inv genes encode a subfamily of apoplastic enzymes which are s hown to be distinct, on the basis of sequence similarity, from the rel ated subfamily of vacuolar enzymes. In order to differentiate between the expression of the two potato genes encoding apoplastic Inv, a sing le-stranded conformational polymorphism (SSCP) assay was developed for products generated by reverse transcription-polymerase chain reaction (RT-PCR) utilising primers designed to amplify both potato sequences. Using this approach, we have shown that these two identified Inv from potato are expressed in a tissue-specific and developmentally regulat ed manner.