Iron (Fe) deficiency leads to an overproduction of reactive oxygen species (ROS) in plants that activate their antioxidant systems to control oxidative burst. In this study, contrasting Medicago truncatula genotypes, A17 and TN8.20 (tolerant) and TN1.11 (sensitive), were grown under Fe deficiency. The superoxide dismutase (SOD: EC1.15.1.1) activity, their isoforms’ coding genes, the copper chaperone expression patterns, and leaf phenolic contents were analysed. Our results showed that Fe deficiency decreases the photosynthetic capacity and plant biomass production with a prominent effect on TN1.11 genotype. The tolerance of A17 and TN8.20 was correlated with a maintenance of Fe content and the photosynthetic apparatus and an increase of Cu concentration compared with the sensitive genotype. We revealed a significant increase of H₂O₂ in Fe-deficient plants, mainly in TN1.11 sensitive genotype. TN8.20 and A17 tolerance were concomitant with a significant increase of SOD activities (SOD, Cu/Zn-SOD, and Mn-SOD) under Fe deficiency. This increment was correlated to an induction of the copper chaperone gene expression level, as well as an accumulation of isoquercitin phenolic compound. Our study provides new insights into the orchestration of SOD’s isoforms activities, the expression of the copper chaperone, FeSOD, Cu/ZnSOD genes, and the leaf phenolic compounds accumulation that allows Medicago truncatula to overcome Fe deficiency.

铁 (Fe) 缺乏会导致植物中活性氧 (ROS) 过量产生，从而激活其抗氧化系统以控制氧化爆发。在本研究中，对比紫花苜蓿基因型 A17 和 TN8.20（耐受）和 TN1.11（敏感）在缺铁条件下生长。分析了超氧化物歧化酶（SOD：EC1.15.1.1）活性、它们的同种型编码基因、铜伴侣蛋白表达模式和叶酚含量。我们的结果表明，缺铁会降低光合能力和植物生物量产生，对 TN1.11 基因型有显着影响。与敏感基因型相比，A17 和 TN8.20 的耐受性与 Fe 含量和光合装置的维持以及 Cu 浓度的增加相关。我们发现 H ₂ O ₂显着增加在缺铁植物中，主要是在 TN1.11 敏感基因型中。TN8.20 和 A17 耐受性伴随着铁缺乏下 SOD 活性（SOD、Cu/Zn-SOD 和 Mn-SOD）的显着增加。这种增加与铜伴侣基因表达水平的诱导以及异槲皮素酚类化合物的积累有关。我们的研究为 SOD 异构体活动的编排、铜伴侣蛋白、FeSOD、Cu / ZnSOD基因的表达以及使苜蓿克服铁缺乏症的叶酚类化合物积累提供了新的见解。