Oxidative post translational modifications of proteins related to cell cycle are involved in cadmium toxicity in wheat seedlings.

LB PENA; RA BARCIA; CE AZPILICUETA; AA MENDEZ; SM GALLEGO

Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2012

SAIB

Abioticstressisgreatlyassociatedwithplantgrowthinhibitionand redox cell imbalance. In the present work, we have investigated in which way oxidative posttranslational modifications (PTM) of proteinsrelatedtocellcyclemaybeimplicatedinpost-germinative root growth reduction caused by cadmium, by methyl viologen (MV) and by hydrogen peroxide (H O ) in wheat seedlings. Although cadmium is considered a redox inactive metal, reactive oxygen species were detected in the apex root of metal-treated seedlings. Oxidative stress hastened cells displacement from the cell division zone to elongation/differentiation zone, resulting in a shortened meristem. The number of cells in the proliferation zone was lower after MV, H O and 10 M Cd treatments compared to control. All treatments increased protein carbonylation. Although no modification in total Ub-conjugated proteins was detected, oxidative treatments reduced cyclin D and CDKA protein ubiquitination, concomitantly with a decrease in expression of cyclin D/CDKA/Rb/E2F-regulated genes. We postulate that ROS and oxidative PTM could be part of a general mechanism, specifically affecting G1/S transition and progression through S phase. This would rapidly block cell cycle progression and would allowthecellulardefencesystemtobeactivated.