The E3 ubiquitin ligases participate in the degradation of plant proteins and play a regulatory role in stress response. However, the role of tomato E3 ubiquitin ligase genes in plant response to heavy metal stress remains elusive. Here, we identified 17 tomato E3 ubiquitin ligase genes using blast analysis of highly expressed E3 ubiquitin ligase genes of Arabidopsis thaliana. Through organ expression analysis, three E3 ubiquitin ligase genes with higher expression levels in roots were further screened out, and they were named Sl1, SlRHE1, and SlRING1. Among these three genes, SlRING1 expression was the highest in response to cadmium (Cd) stress. Silencing SlRING1 significantly decreased chlorophyll content, Fv/Fm, photosynthetic rate, and biomass accumulation under Cd stress. The levels of H₂O₂, electrolyte leakage, and malondialdehyde significantly increased in SlRING1–silenced plants under Cd stress compared with that in non-silenced tomato plants. Cd stress-induced increases in the transcript levels of antioxidant and detoxification genes such as CAT, DHAR, MDHAR, GSH, and PCS were compromised by SlRING1 silencing. Moreover, Cd accumulation in shoots and roots significantly increased in SlRING1-silenced plants compared with non-silenced tomato plants. These findings suggest that SlRING1 plays a positive role in plant tolerance to Cd stress in tomato.

E3泛素连接酶参与植物蛋白的降解并在应激反应中发挥调节作用。然而，番茄 E3 泛素连接酶基因在植物对重金属胁迫的反应中的作用仍然难以捉摸。在这里，我们使用对拟南芥的高表达 E3 泛素连接酶基因的爆炸分析鉴定了 17 个番茄 E3 泛素连接酶基因。通过器官表达分析，进一步筛选出根中表达水平较高的3个E3泛素连接酶基因，分别命名为Sl1、SlRHE1和SlRING1。在这三个基因中，SlRING1表达对镉 (Cd) 胁迫的响应最高。沉默SlRING1显着降低了镉胁迫下的叶绿素含量、Fv/Fm、光合速率和生物量积累。与非沉默番茄植株相比，Cd 胁迫下SlRING1沉默植株的 H ₂ O ₂、电解质泄漏和丙二醛水平显着增加。Cd 应激诱导的抗氧化和解毒基因（如CAT、DHAR、MDHAR、GSH和PCS）转录水平的增加受到SlRING1沉默的影响。此外，与非沉默番茄植物相比，SlRING1沉默植物的芽和根中的 Cd 积累显着增加。这些发现表明SlRING1 在番茄对镉胁迫的耐受性中起积极作用。