Abstract
Transgenic potato microtubers were created in which the expression of sucrose synthase (Susy) was altered by introducing a chimeric gene containing the coding region of Susy that is linked to the patatin promoter in sense (S) or antisense (AS) orientation. The analysis of transgenic microtubers showed that Susy activity and starch content increased in S plants 8, 22, and 30 transformed with the chimeric sense gene ; they decreased in AS plants 3 and 10 transformed with the antisense gene. RT-PCR analysis revealed that the level of mRNA for Susy increased in S plants, and decreased in AS plants. There was a little change in the expression of genes for ADP-glucose pyrophosphorylase (AGPase), one of key enzymes in starch biosynthesis. The level of mRNA for AGPase and the activity of the enzyme increased in S 8 plant, but decreased in AS 3 plant.
