Cadaverine turnover in soybean seedlings using 15N-labelled lysine and cadaverine

The synthesis and translocation of the diamine cadaverine during soybean (Glycine max L Meer cv. Sakai) germination were studied using N-15-labelled lysine (the cadaverine precursor) and N-15-labelled cadaverine, both under light/dark (12 h/12 h) and total dark germinating conditions. N-15-cadaverine and non-labelled polyamines were simultaneously detected using ionspray ionization mass spectrometry. Both N-15-cadaverine and N-15-lysine were taken up by soybean. N-15-lysine was transported to the shoot and root and converted into N-15-cadaverine, whereas relatively little N-15-cadaverine was formed from N-15-lysine in the cotyledon. The acropetal translocation of N-15-cadaverine from the cotyledon to the shoot seemed to predominate over basipetal transport to the root. Although no other N-15-derivatised polyamines were found, supplying exogenous N-15-lysine seemed to indirectly affect the metabolism of N-14 putrescine, spermidine and spermine, while no significant effect was detected after supplying N-15-cadaverine. (C) 2010 Elsevier Masson SAS. All rights reserved.