MiR5651, miR170-3p, and miR171a-3p Regulate Cadmium Tolerance by Targeting in .

The DNA mismatch repair (MMR) system plays a crucial role in repairing DNA damage and regulating cell cycle arrest induced by cadmium (Cd) stress. To elucidate the mechanism by which miRNAs target in regulating ' response to Cd stress, the wild-type , mutant, and three miRNA-overexpressing transgenic lines were grown hydroponically in half-strength MS solution containing cadmium (Cd) at concentrations of 0, 0.5, 1, 2, and 3 mg/L for 5 days. miRNA-seq analysis, bioinformatics prediction, dual-luciferase reporter assays, and qRT-PCR results demonstrated that miR5651, miR170-3p, and miR171a-3p specifically targeted and their expression levels showed a significant negative correlation. Compared to wild-type (WT) , Cd stress tolerance was significantly enhanced in miRNA-overexpressing transgenic lines. Moreover, exogenous application of these three miRNAs in half-strength MS liquid medium also markedly improved Cd stress tolerance in wild-type . Furthermore, the expression of these three miRNAs expression was further upregulated by Cd stress in a dose-dependent manner. Additionally, DNA damage response in miRNA-overexpressing transgenic lines was promoted based on the expression of DNA repair, DNA damage signaling, and cell cycle genes, which differed from both wild-type and plants. Taken together, miR5651, miR170-3p, and miR171a-3p participated in Cd stress response and improved plant Cd tolerance by mediating the expression of . Our study provides novel insights into the epigenetic mechanisms of Cd tolerance in plants, which sheds light on breeding for stress resilience in phytoremediation.