GROWTH MODIFICATIONS AND OXIDATIVE STRESS IN SEEDLINGS OF DIFFERENT MAIZE HYBRIDS SUBJECTED TO CADMIUM AND COPPER STRESS

MATAYOSHI C; HERNANDEZ E; LOIS M; BENAVIDES MP; GALLEGO S

Congreso; Reunión Conjunta de Sociedades de Biociencias.; 2017

Maize is one of the most important agronomical crops. It is usedin the human diet and it is considered an interesting source for theproduction of biofuels. Since early seedling growth is critical in plantlife cycle, the effect of Cd (a redox inactive metal) and Cu (a redoxactive metal) on growth parameters of 10 commercial Zea maysL. hybrids (labelled H1 to H10) was analyzed at this stage. Maizeseeds were germinated on filter paper in plastic dishes containingdistilled water. Seedlings of a comparable size with roots of 1-2 cmlength were selected and transferred to hydroponic culture without(control, C) or containing an aqueous solution of 100 μM CdCl2 orCuCl2. They were grown in a controlled climate room at 24±2°C indarkness during 72 h. For statistical analysis of growth parameters,a hierarchical model factorial design was applied, taking ?H? as factorA, and ?treatments (C, Cd, Cu)? as factor B nested in A. Despitemetals significantly decreased root and coleoptile length, fresh anddry weight, no statistically significant interaction was detected betweengenotypes and metals treatment. Metals increased oxidativeprotein damage in roots and decreased transcript accumulation ofthe gene family from the enzyme methionine sulfoxide reductase(MSR): ZmMSRA4, ZmMSRA5.1, ZmMSRB1, ZmMSRB5.1 in theroot apex. Further analysis in root apex of H10 showed that proteinconjugation pattern with SUMO and ubiquitin were modified duringmetal treatment. In addition to previous data obtained in our laboratory,the present results indicate that the oxidative posttranslationalmodifications (PTM) produced during abiotic stress could be a nexusbetween stress recognition and growth reprogramming. Despitefurther studies are needed, we propose that this could be an interestingmechanism where oxidative PTM regulates another PTMslike sumoylation and ubiquitination as part of the signalling processduring abiotic stress.Keywords: Maize, Abiotic Stress, Metals, Oxidative posttranslationalmodification