Page, Andrew , Minocha, Rakesh , Minocha, Subhash .
Global impact of genetic manipulation of polyamines.
Plant biotechnological endeavors often entail a deliberate modification of metabolism. In most cases the intention is to target only a specific step with minimal impact on other parts of metabolism. We studied the impact of genetic manipulation of the cellular content of a polyamine (PA), putrescine, on the entire transcriptome of poplar (Populus nigra x maximowiczii) cells using microarrays. The two cell lines used here included one (HP) that accumulates 4-5-fold higher amounts of putrescine (due to overexpression of an ornithine decarboxylase gene) and a control cell line (expressing a GUS gene). The underlying hypothesis was that genetic manipulation of PA biosynthesis may result not only in changes in expression of genes involved in PA metabolism, but may also have far more distal effects on the expression of genes which would be difficult to predict based only on traditional biochemical and molecular analyses. We indeed found that the cellular effects of genetic manipulation of putrescine go beyond the network of PA and related metabolic pathways. On day three of culture, 913 ESTs showed significantly different expression between control and HP cells; 448 were upregulated and 465 were downregulated in the latter. On day five, the expression of 1538 ESTs was different between the two cell lines; 862 were upregulated in HP cells and 672 were downregulated. There were 416 ESTs whose expression was significantly different between control and HP cells on both days. Among them are the genes involved in various enzymatic functions as well as those affecting transcription and translation, membrane transport and osmoregulation, biosynthesis of cell wall, heat-shock, stress and wound response, and a myriad of others whose function has not been characterized.
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1 - University of New Hampshire, Plant Biology
2 - NE Research Station, USDA Forest Service, 271 Mast Road, P.O. Box 640, Durham, New Hampshire, 03824, USA
3 - University of New Hampshire, Plant Biology, Rudman Hall, Durham, NH, 03824, USA
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM