Polyamines (PA) are naturally occurring low molecular weight aliphatic amines found in all living organisms and essential for their growth and development. The present study uses the tool of transgenic manipulation to elucidate the regulation of PA pathway in poplar cells. This study was divided into two segments; the first segment provides insight into biochemistry of a putrescine overproducing cell line (HP) that overexpresses a mouse ornithine decarboxylase (mODC) under 35S-CaMV promoter, with respect to different treatments. The second segment focused on creation and biochemical characterization of a cell line (SOS1) that overexpresses ODC/SAMDC from Plasmodium falciparum controlled by the same 35S-CaMV promoter producing a bifunctional protein.

From the results it is concluded that: (i) nutrient stress in the form of Ca deficiency in the growth medium is more detrimental to HP cells than control cells, (ii) the tested PA analogues and inhibitors at the tested concentrations have no major observable effect on either HP or the control cells, (iii) Cysteine and methionine although consumed faster in HP cells, are not limiting either for protein synthesis or for growth, (iv) uptake of sucrose is higher in the control cells but its incorporation into PAs is higher in HP cells, (v) SOS1 cells after stable integration of PfODC/SAMDC produce significantly increased amounts of Spd and Spm than control cells, and (vi) the simultaneous expression of both SAMDC and ODC from Plasmodium has greater impact on production of Spd/Spm than on Put in SOS1 cells.