POLYAMINE CATABOLISM IN THE ELONGATION ZONE CONTRIBUTS TO SUSTAIN SOYBEAN HYPOCOTYLES GROWTH UNDER SALT STRESS

MARIA PAULA CAMPESTRE; SANTIAGO JAVIER MAIALE; CESAR DANIEL BORDENAVE; ANDREA CECILIA ORIGONE; OSCAR ADOLFO RUIZ; ANDRÉS ALBERTO RODRÍGUEZ

La Plata

Congreso; XXVIII Reunión Argentina de Fisiología Vegetal; 2010

Objetive: The possible relationship between polyamine catabolism by copper-containing amine oxidase and hypocotyl growth of salinized soybean has been studied. Results: Salt treatment increased spermine and mainly, cadaverine level in hypocotyls. Copper-containing amine oxidase activity level was up to 77-fold higher that of the polyamine oxidase. Copper-containing amine oxidase was active even in salinity and showed highest affinity to cadaverine than putrescine. In vivo determination of copper-containing amine oxidase activity in presence of cadaverine, showed an increase with saline treatment modulated negatively in treatment added with diaminoguanidine, a competitive inhibitor. The same effects of cadaverine and diaminoguanidine were observed in hypocotyl growth assays of under optimal or unfavourable conditions. Additionally, plants treated with diaminoguanidine showed a significative reduction of reactive oxygen species in the elongation zone of hypocotyl detected by DCF fluorescence. Conclusions: These results demostrated that copper-containing amine oxidase activity produced hydrogen peroxide by polyamine catabolism in salinity and this hydrogen peroxide production may be contributing to hypocotyl growth partially under saline stress.