Cadmium toxicity in transgenic tobacco catalase-deficient plants.

IANNONE MF; BOCCARDO NA; DE GYNDENFELDT E; GROPPA MD; BENAVIDES MP

Congreso; XLVIII Reunión Anual SAIB. 48th Annual Meeting.; 2012

SAIB

Cadmium is a toxic pollutant that produces oxidative stress in several plant species. The aim of this work was to evaluate Cd toxicity in transgenic tobacco catalase-deficient (CAT1AS) and wild type plants (SR1). Plants of 45 d were treated for 8, 13, 25 days with 100 μM or 500 μM CdCl2. At day 25, CAT1AS plants accumulated more Cd than SR1 and showed smaller growth. At 25 d, iron and nitrates content decreased only in SR1 plants treated with 500μMCd. Chlorophyll content was reduced in both lines but more markedly in SR1. This was correlated with an increased expression of , a senescence-associated gene. Ascorbate peroxidase (APOX), catalase (CAT) and guaiacol peroxidase (GPOX) activities significantly increased with 500 μM Cd in both lines, except for CAT activity, that was undetectable in CAT1AS. At 25 d, CAT1AS plants counterbalanced their CAT deficiency by increasing the basal GPOX and APOX activities. In SR1 plants, 100 μM Cd augmented cell death, electrolyte leakage, and decreased polyamines (PAS) content at 25 d. SR1 plants treated with 500μMCd recovered cell viability and this could be due to the increase of the antioxidant enzymes activities, GSH and PAS content. Only CAT1AS plants increased proline content at all evaluated times. These results show thatCAT1AS plants are able to activate different alternative defence mechanisms against Cd toxicity compared to SR1