|
|
||||||||
|
Plant Physiology Preview Published on June 28, 2002; 10.1104/pp.010966
Received October 22, 2001 Expression of a Heterologous S-Adenosylmethionine Decarboxylase cDNA in Plants Demonstrates That Changes in S-Adenosyl-L-Methionine Decarboxylase Activity Determine Levels of the Higher Polyamines Spermidine and Spermine
John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom * Corresponding author; email: teresa.capell{at}ime.fraunhofer.de.
We posed the question of whether steady-state levels of the higher polyamines spermidine and spermine in plants can be influenced by overexpression of a heterologous cDNA involved in the later steps of the pathway, in the absence of any further manipulation of the two synthases that are also involved in their biosynthesis. Transgenic rice (Oryza sativa) plants engineered with the heterologous Datura stramonium S-adenosyl-methionine decarboxylase (samdc) cDNA exhibited accumulation of the transgene steady-state mRNA. Transgene expression did not affect expression of the orthologous samdc gene. Significant increases in SAMDC activity translated to a direct increase in the level of spermidine, but not spermine, in leaves. Seeds recovered from a number of plants exhibited significant increases in spermidine and spermine levels. We demonstrate that overexpression of the D. stramonium samdc cDNA in transgenic rice is sufficient for accumulation of spermidine in leaves and spermidine and spermine in seeds. These findings suggest that increases in enzyme activity in one of the two components of the later parts of the pathway leading to the higher polyamines is sufficient to alter their levels mostly in seeds and, to some extent, in vegetative tissue such as leaves. Implications of our results on the design of rational approaches for the modulation of the polyamine pathway in plants are discussed in the general framework of metabolic pathway engineering.
This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| ASPB Publications | PLANT PHYSIOLOGY® | THE PLANT CELL | |
|---|---|---|---|