ISSN:
1573-5028
Keywords:
glucuronidase
;
post-transcriptional regulation
;
transgenic plants
;
tuber
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Analysis of the levels of starch phosphorylase mRNA and its product in the various organs of the potato plant indicates that the gene is differentially regulated, leading to a high accumulation of the gene product in tubers. The amount of phosphorylase transcripts synthesized in nuclei isolated from tubers and leaves indicates that the difference in the steady-state levels of phosphorylase mRNA in these organs can be explained by different rates of initiation of transcription. However, while rates of initiation of transcription are similar in tubers and stems, the steady-state level of phosphorylase mRNA is much lower in the stem. Transgenic potato plants expressing the β-glucuronidase (GUS) gene under the control of 5′-flanking sequences of the phosphorylase gene exhibited high levels of GUS activity in petioles, stems, stolons, tubers and roots, but low levels in leaves. This confirms the results of transcription assays observed for leaves, stems and tubers, and indicates that accumulation of phosphorylase mRNA in stems and tubers is not controlled solely by transcription initiation. Finally, histochemical analysis for GUS activity in transgenic potato plants suggests that transcription of the phosphorylase gene predominantly occurs in starch-containing cells associated to vascular tissues, and suggests a role for starch phosphorylase in the mobilization of starch stored along the translocation pathway.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00019544
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