Transgenic potatoes having reduced levels of alpha glucan l- or h-type tuber phosphorylase activity with reduced cold-sweetening

摘要

Potato plants which exhibit reduced levels of alpha glucan L-type tuber phosphorylase (GLTP) or alpha glucan H-type tuber phosphorylase (GHTP) enzyme activity within the potato tuber are provided. The conversion of starches to sugars in potato tubers, particularly when stored at temperatures below 7 DEG C, is reduced in tubers exhibiting reduced GLTP or GHTP enzyme activity. Reducing cold-sweetening in potatoes allows for potato storage at cooler temperatures, resulting in prolonged dormancy, reduced incidence of disease, and increased storage life. Methods for producing potato plants which produce tubers exhibiting reduced GLTP or GHTP enzyme activity are also provided. Reduction of GLTP or GHTP activity within the potato tuber may be accomplished by such techniques as suppression of gene expression using homologous antisense RNA, the use of co-suppression, regulatory silencing sequences, chemical and protein inhibitors, or the use of site-directed mutagenesis or the isolation of alternative alleles to obtain GLTP or GHTP variants with reduced starch affinity or activity.