Upregulation of LeNRAMP3 and LeFER Genes in Solanum lycopersicum Confers Its Cadmium Tolerance

Nanoparticles are used in all aspects of modern life, especially in agriculture. This research investigated the effect of foliar spray of silicon oxide nanoparticles (nano-SiO 2 ) at 0, 25, 50 and 50–100 mg/L concentrations on physiological and molecular characteristics of tomato ( Solanum lycopersicum L.) plant under 0, 100, and 200 µM CdCl 2 . Cadmium (Cd) had a negative effect on growth and decreased the uptake of most nutrients with a dual impact on iron. Mild stress increased the iron uptake but severe stress decreased it. Two key genes involved in iron homeostasis were examined, namely LeNRAMP3 (natural resistance-associated macrophage proteins) and LeFER (FER like iron deficiency-induced transcription factor). The qRTPCR results indicated that increasing expression of both genes was essential for maintaining Cd stress tolerance in tomato. As an intermediate, nano-SiO 2 had a constructive and effective role in alleviating the inhibitory effects of Cd on growth and uptake of nutrients. Upregulation of LeNRAMP3 and LeFER genes confirmed better nutritional status of tomato plant treated with 50 mg/L nano-SiO 2 than other treatments under Cd stress.