Cadmium affects wheat plants growth through oxidative damage of celular cycle proteins.

AZPILLICUETA CE; PENA LB; PASQUINI LA; TOMARO ML; GALLEGO SM

Mar del Plata, Buenos Aires, Argentina

Congreso; XLIII Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2007

SAIB

In this work we analyze if oxidative stress produced by Cd alters the Ub-proteasome system, causing modifications in the cellular cycle, and thus influencing plant growth. Triticum aestivum L. seeds were floated for 48 h on distillated water or exposed to 1, 10 and 100 µM Cd or 0.5 and 1 µM paraquat or 100 and 1000 µM H2O2, under dark conditions. The highest Cd concentration inhibited seed germination. All treatments caused inhibition of primary root length. Root membrane permeability increased 41, 99 and 66% only with 1, 10 µM Cd and 1000 µM H2O2, respectively. Total soluble protein level was unaffected by Cd, but it diminished the Ub-conjugated protein level and increased oxidized proteins. Proteasoma activities varied with the metal addition. Under these treatments, abundance of 20S proteasoma protein remained constant and no protein fragmentation was observed. The abundance of cyclin D protein was unaffected by Cd, but the level of Ub-cyclin D decreased and increased oxidized cyclin level. Analysis CDKD2 showed that this protein abundance, degree of Ub-conjugation and oxidation were not affected significantly with 1 µM Cd, whereas 10 µM Cd increased only protein oxidation. These results suggest that Cd and other prooxidants affects plant growth by oxidation of cell cycle proteins that regulate proliferation and protein recycling.