title: Heme oxygenase and catalase gene expression in nodules and roots of soybean plants subjected to cadmium stress.
abstract: Heme oxygenase (HO, EC 1.14.99.3) catalyses the oxidative conversion of heme to biliverdin IX alpha (BV) with the concomitant released of carbon monoxide and iron. Recently, plant HOs have been involved in the defence mechanism against oxidative stress. The goal of this study was to evaluate the time-course of HO-1 and catalase (CAT, EC 1.11.1.6) gene expressions in nodules and roots of soybean plants subjected to Cd treatment. No significant changes were observed up to 24 h. After 48 h of 200 microM Cd exposure, an up-regulation of HO-1 mRNA (110%) occurred in nodules. On the other hand, a down-regulation was found in roots (39%). While there was an augmentation in CAT transcript levels (30%) in nodules, an important diminution (52%) was evidenced in roots. Changes observed in gene expression were also found in protein levels and activities. These data suggest that an induction of CAT and HO-1 occurred in nodules as a response of cell protection against oxidative damage. However, after 72 h treatment, a down-regulation of HO-1 mRNA was found either in nodules or in roots (78% and 94%, respectively), while a similar response was evidenced for CAT (40% and 83%, respectively). These results are consistent with our previous findings suggesting that oxidative stress produced by Cd were more pronounced in roots than in nodules of soybean plants. Moreover, this behaviour could explain the major viability observed in nodules respect to roots, and provide a new insight into the processes involved in the antioxidant defence system in plant tissues.
authors.affiliation: Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, Argentina.
authors.forename: Karina B
authors.initials: KB
authors.lastname: Balestrasse
authors.forename: Gustavo G
authors.initials: GG
authors.lastname: Yannarelli
authors.forename: Guillermo O
authors.initials: GO
authors.lastname: Noriega
authors.forename: Alcira
authors.initials: A
authors.lastname: Batlle
authors.forename: Maria L
authors.initials: ML
authors.lastname: Tomaro
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002104:Cadmium / Q000494:pharmacology*; D002374:Catalase / Q000235:genetics* / Q000378:metabolism; D004790:Enzyme Induction; D018506:Gene Expression Regulation, Plant; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology*; D013025:Glycine max / Q000033:anatomy & histology / Q000187:drug effects / Q000201:enzymology*
chemical_list: D000975:Antioxidants; D010940:Plant Proteins; D002104:Cadmium; D002374:Catalase; D006419:Heme Oxygenase (Decyclizing)