No abstract

Heavy metal contamination affects crop growth and development and can indirectly threaten human health. Therefore, improving the content of microelements and reducing the accumulation of toxic metals by genetic breeding in crops is an effective strategy to solve this environmental problem. Previous reports show plant cadmium resistance (PCR) protein can transport zinc (Zn) and cadmium (Cd). The cell number regulator (CNR) protein, which functions to regulate organ size, has high similarity to, and shares conserved motifs with, PCR. Therefore, CNR may be involved in regulating heavy metal translocation. We isolated TuCNR10 from diploid wheat, Triticum urartu. Realtime quantitative PCR showed TuCNR10 expression increased in the shoots and roots of seedlings under Cd, Zn, and manganese (Mn) stresses. Confocal imaging indicated TuCNR10 was localized at the plasma membrane. Overexpression of TuCNR10 in Arabidopsis and rice enhanced Cd, Zn, and Mn tolerance and improved Cd, Zn, and Mn translocation from roots to shoots. Compared with wild-type rice, rice overexpressing TuCNR10 had lower Cd and higher Zn and Mn contents in grains. These results indicated that TuCNR10 may be a transporter of Cd, Zn, and Mn. TuCNR10 may be a useful genetic resource for microelement fortification and reducing toxic metal accumulation in crops.

Soil microelement deficiency and heavy metal contamination affects plant growth and development, but improving trace element uptake and reducing heavy metal accumulation by genetic breeding can help alleviate this. Cell number regulator 2 (TaCNR2) from common wheat (Triticum aestivum) are similar to plant cadmium resistance proteins, involved with regulating heavy metal translocation. Our aim was to understand the effect of TaCNR2 on heavy metal tolerance and translocation. In this study, real-time quantitative PCR indicated TaCNR2 expression in the wheat seedlings increased under Cd, Zn and Mn treatment. Overexpression of TaCNR2 in Arabidopsis and rice enhanced its stress tolerance to Cd, Zn and Mn, and overexpression in rice improved Cd, Zn and Mn translocation from roots to shoots. The grain husks in overexpressed rice had higher Cd, Zn and Mn concentrations, but the brown rice accumulated less Cd but higher Mn than wild rice. The results showed that TaCNR2 can transport heavy metal ions. Thus, this study provides a novel gene resource for increasing nutrition uptake and reducing toxic metal accumulation in crops.