Polyamine content and somatic embryogenesis in Papaver somniferum cells transformed with sam-1 gene

Papaver somniferum calluses transformed with the sam-1 gene from Arabidopsi s thaliana, which encodes a SAM-synthetase, were subcultured over a 4-year period. The stability of the expression as well as the level of SAM synthet ase activity were evaluated in 5 transgenic cell lines (STSI, STSII, STSIII , STSIV, STSV) and in the control. All transgenic cell lines exhibited a le vel of SAM-synthetase activity higher than that of the control. The enhance ment of the enzyme activity has been confirmed by Northern blot analyses. T he level of polyamines (putrescine, spermidine, spermine and 1,3-diaminopro pane) was also evaluated in cell lines cultured either in Linsmaier and Sko og medium containing growth regulators (LS) or on a hormone free medium (LS HF). Cell lines cultured in LS medium showed a variable yield of the polyam ine content. Putrescine was the major polyamine. After transfer to a hormon e free medium, all of the cell lines, except STSIV, were able to form embry o-like structures. In this condition, the polyamine level decreases about 4 -fold, spermidine being the most abundant.