Plant Genome III Conference Plant Genome III Conference
Metabolism of sucrose is an essential element of plant vital activity. The protein level of regulation of the pathway is well investigated while the genetic component remains almost unknown. To fill this gap in our knowledge of the pathway, promoter regions of the genes of two key enzymes of the pathway, UDP glucose pyrophosphorylase and sucrose synthase, have been isolated. A series of stepwise deletions of the promoters fused with - glucoronidase coding sequences were constructed and used for a particle bombardment. The results of the analysis showed the presence of a non-coding 5'proximal end and two transcriptional starts in both potato genes. A model of dual regulation of expression of these two genes was proposed. This dual regulation is realized through the presence of two independent promoters in structure of the genes driving different transcripts from different start points in different tissues or/and under different physiological conditions. The physiological role of such organization is discussed.