Toxicologie Végétale & Biologie Moléculaire des Microorganismes, Faculté des Sciences de Bizerte, 7021, Zarzouna, Bizerte, Tunisia,
Environ Sci Pollut Res Int. 2014;21(13):8070-83. doi: 10.1007/s11356-014-2718-x. Epub 2014 Mar 26.
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.
在六种蒺藜苜蓿基因型的早期幼苗生长中，存在 Cd 毒性时会引发氧化损伤。根生长抑制、镉吸收以及氧化损伤的发生之间的相互作用表明，不同基因型存在不同的反应，包括敏感型和耐受型。观察到原位 ROS 增强，测量了 H₂O₂含量，但似乎与耐受性或敏感性无关。氧化爆发对细胞膜完整性的影响与 MDA 含量和葡萄糖分泌分析一致，这表明这种爆发在敏感系中具有积极作用。对镉处理的靶基因转录变化进行了分析，这些基因涉及 (1)ROS 清除酶（超氧化物歧化酶 (SOD; EC1.15.1.1) 和过氧化物酶 (PRX; EC 1.11.1.7)）、(2) 还原型谷胱甘肽 (γ-Glu-Cys-Gly，GSH) 代谢（谷胱甘肽-S-转移酶 (GST; EC: 2.5.1.18) 和谷胱甘肽还原酶 (GR; EC 1.8.1.7)）和 (3) 金属螯合代谢（PCS）。敏感型系没有表现出反应或非及时的基因表达模式。这项研究工作概述了 Cd 胁迫对蒺藜苜蓿的有害影响和氧化损伤。氧化防御效率和基因上调应该可以解释测试基因型的相对耐受性。
