CADMIUM TOXICITY IN TRANSGENIC TOBACCO CATALASE DEFICIENT PLANTS

IANNONE M.F.; BOCCARDO N.A.; DE GYLDENFELDT E.; GROPPA M.D.; BENAVIDES M.P.

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

CADMIUM TOXICITY IN TRANSGENIC TOBACCO CATALASE DEFICIENT PLANTS Iannone MF, Boccardo NA, de Gyldenfeldt E, Groppa MD, Benavides MP Dpto de Química Biológica, FFyB, UBA. Junín 956, CABA, Argentina. Email: mflorenciaiannone@gmail.com Cadmium is a toxic pollutant that produces oxidative stress in several plants species. The aim of this work was to evaluate Cd toxicity in transgenic tobacco catalase-deficient plants (CAT1AS) and wild type (SR1). Plants from 45-day-old were treated for 8, 13, 25 days with 100µM or 500µM CdCl2. At 25 d, CAT1AS plants accumulated more Cd than SR1 and this was reflected in lower growth. At 25 d, the iron and nitrate content decreased only in SR1 plants treated with 500μM Cd, while the chlorophyll content was reduced in both lines but more in SR1, which correlated with an increase in cp1 gene expression, a SAG gene associated with senescence. Ascorbate peroxidase (APOX), catalase (CAT) and guaiacol peroxidase (GPOX) activities increased significantly with 500μM Cd in both lines, except that CAT was undetectable in CAT1AS. At 25 d CAT1AS plants compensated their CAT deficiency increasing the basal GPOX and APOX activity. In SR1 plants, 100µM Cd augmented cell death, electrolyte leakage, but decreased polyamines content at 25 d. SR1 plants treated with 500μM Cd showed a recovery in cell viability and this could be due to the increase of the antioxidant enzymes activity, GSH and PAS content. Only CAT1AS plants increased proline content at all times tested. These results show that CAT1AS plants are able to activate different alternative defence mechanisms than SR1 in response to Cd.