Modulation of spermidine and spermine levels in maize seedlings subjected to long term saline stress

FRANCISCO JIMENEZ BREMONT, OSCAR A RUIZ & MARGARITA RODRIGUEZ-KESSLER

PLANT PHYSIOLOGY AND BIOCHEMISTRY

Año: 2007 vol. 45 p. 812 - 821

0981-9428

Salinity is one of the major abiotic stresses affecting plant agriculture worldwide. Polyamines, a group of aliphatic amines, are known to accumulate under salt stress conditions in different plant systems, resulting in presumed protective effects, acting as free radical scavengers, stabilizing cellular membranes and maintaining cellular ionic balance under these conditions. In the present study, we measured the polyamine content of maize seedlings subjected 1 and 7 days of salt stress. We observed that under stress maize plants tend to maintain or accumulate the levels of spermidine and spermine, while putrescine levels fluctuate depending on the NaCl concentration. In addition, we analyzed the expression of the adc, samdc, Zmspds1 and Zmspds2 polyamine biosynthetic genes under these conditions. Our data show a time and NaCl dependent regulation of the Zmspds2 and Zmspds1 genes, suggesting that the former might be hyperosmotic responsive while the later NaCl responsive. Interestingly, the maize adc, Zmspds1 and Zmspds2 genes are regulated at the transcriptional level by the plant hormone abscisic acid. A connection between polyamine metabolism, abiotic stress and abscisic acid is discussed.