title: Oxidative injury and antioxidant genes regulation in cadmium-exposed radicles of six contrasted Medicago truncatula genotypes.
abstract: Oxidative disorders were triggered in the presence of Cd toxicity in early seedling growth of six Medicago truncatula genotypes. Interactions between root growth inhibition, cadmium uptake, as well as the occurrence of oxidative injury suggest differential responses of the genotypes, with susceptible or tolerant accessions. ROS enhancement was observed in situ and H₂O₂ content was measured, that did not seem related to tolerance or susceptibility. Oxidative burst impact on cell membrane integrity was analyzed in agreement with MDA content and glucose exudation, which suggest an active role of this burst in susceptible lines. Transcriptional changes in response to cadmium treatment were analyzed on target genes involved in (1) ROS-scavenging enzymes (superoxide dismutase (SOD; EC1.15.1.1) and peroxidase (PRX; EC 1.11.1.7)), (2) reduced glutathione (γ-Glu-Cys-Gly, GSH) metabolism (glutathione-S-transferase (GST; EC: 2.5.1.18) and glutathione reductase (GR; EC 1.8.1.7)), and (3) metal-chelating metabolism (PCS). The susceptible line shows no response or non-timely gene expression patterns. This research work gave an overview of the deleterious effects and oxidative injury of cadmium stress in Medicago truncatula. Oxidative defense efficiency and gene upregulation should explain relative tolerance in tested genotypes.
authors.affiliation: Toxicologie Végétale & Biologie Moléculaire des Microorganismes, Faculté des Sciences de Bizerte, 7021, Zarzouna, Bizerte, Tunisia, rahoui.sondes@yahoo.fr.
authors.forename: Sondès
authors.initials: S
authors.lastname: Rahoui
authors.forename: Cécile
authors.initials: C
authors.lastname: Ben
authors.forename: Abdelilah
authors.initials: A
authors.lastname: Chaoui
authors.forename: Yves
authors.initials: Y
authors.lastname: Martinez
authors.forename: Ahad
authors.initials: A
authors.lastname: Yamchi
authors.forename: Martina
authors.initials: M
authors.lastname: Rickauer
authors.forename: Laurent
authors.initials: L
authors.lastname: Gentzbittel
authors.forename: Ezzeddine
authors.initials: E
authors.lastname: El Ferjani
mesh_terms: D000704:Analysis of Variance; D002104:Cadmium / Q000633:toxicity*; D017931:DNA Primers / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D005838:Genotype; D005980:Glutathione Reductase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D046913:Medicago truncatula / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D018384:Oxidative Stress / Q000187:drug effects* / Q000235:genetics; D010544:Peroxidases / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development; D060888:Real-Time Polymerase Chain Reaction; D016897:Respiratory Burst / Q000187:drug effects / Q000502:physiology; D036226:Seedlings / Q000187:drug effects* / Q000254:growth & development; D013045:Species Specificity; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D017931:DNA Primers; D002104:Cadmium; D006861:Hydrogen Peroxide; D010544:Peroxidases; D013482:Superoxide Dismutase; D005980:Glutathione Reductase