Resumo

PEREZ, Sandra; AHMED, Ahmed I S  e  CABEZAS, Daniel. Molecular and biochemical characterization of tomato (Solanum lycopersicum L.) plants cv. Micro-Tom under lead (Pb)-induced stress. Biotecnol Apl [online]. 2013, vol.30, n.3, pp.194-198. ISSN 1027-2852.

Two different Pb concentrations (5 and 10 mg/kg of PbAc2) were used to study the response of Solanum lycopersicum L. cv. Micro-Tom (MT) plants in two vegetative growth phases. Two genes that have been previously reported to be heavy metal inducible genes (superoxide dismutase, SOD, EC 1.15.1.1; and isoflavone reductase, IFR; EC 1.6.4.2) and another one putatively interesting in this field (transcriptionally controlled tumor protein, TCTP) were selected for an expression study using a real time PCR technique. In the first growth phase (germination to flowering) TCTP was repressed at 10 mg/kg and in the control, SOD expression was low at both concentrations (5 and 10 mg/kg of PbAc2) and IFR was higher at 10 mg/kg PbAc2. In the second phase (flowering to fructification) three genes were expressed in both concentrations but in the case of TCTP and SOD the expression was higher at 5 mg/kg of PbAc2. SOD and Glutathione reductase (GR; EC 1.6.4.2) were selected for a biochemical study together with the determination of protein concentration using spectrophotometer. SOD was higher at 10 mg/kg PbAc2 showing significant difference with control, and GR had the same behavior but had significant differences with the other two treatments while total proteins were higher for the control showing significant differences at 10 mg/kg of PbAc2. This research suggests that Pb toxicity leads to the induction of key enzymes of antioxidant defense system in tomato plants.

Palavras-chave : tomato; heavy metals; expression study; molecular mechanism; abiotic stress; lead.

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