The mechanism of KpMIPS gene significantly improves resistance of Koelreuteria paniculata to heavy metal cadmium in soil.

Cadmium (Cd) pollution in soil is an important factor endangering plant growth and harming human health through food chains. Koelreuteria paniculata is an important woody plant for ecological restoration of Cd-contaminated soils. In this study, KpMIPS gene of K. paniculata was cloned, and the expressed protein (60 kDa) had 1-phosphate synthase activity. The results showed that KpMIPS significantly promoted root development of K. paniculata and Arabidopsis thaliana, reduced damage to the roots of Arabidopsis thaliana caused by Cd, and decreased transfer of Cd to the aboveground parts of K. paniculata and Arabidopsis thaliana . In the K. paniculata plants overexpressing KpMIPS integrity of the root cells was maintained and the content of pectin and phytic acid was significantly increased. Overexpression of KpMIPS increased the Cd accumulation in the roots and decreased the Cd content in the stems and leaves. Clearly, KpMIPS could regulate the contents of pectin and phytic acid in K. paniculata, thereby passivating Cd and enriching it in the root cell wall, reducing the transfer of free Cd to other parts of K. paniculata, and providing a positive regulatory effect on the Cd resistance of K. paniculata. The results of the study provide a technical introduction for the selection and genetic improvement of target genes regulating heavy metal resistance of plants in phytoremediation technology.