Wheat Cell Number Regulator CNR10 Enhances the Tolerance, Translocation, and Accumulation of Heavy Metals in Plants

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.

Mutation in OsFWL7 Affects Cadmium and Micronutrient Metal Accumulation in Rice

“…Cd is a major heavy metal contaminant that is highly toxic to both plants and humans. Previous studies have suggested that plant FWL genes play vital roles in the uptake and translocation of Cd [29,31,32,35,36,38]. In the present study, both the uptake and rootto-shoot translocation of Cd were reduced in the osfwl7 mutants compared with the WT plants under Cd exposure (Figure 3).…”

“…AtPCR2 forms homo-oligomers in the plasma membrane and mediates Zn transport in Arabidopsis [30]. Additionally, overexpression of the common wheat FWL gene TaCNR2 and the diploid wheat FWL gene TuCNR10 in Arabidopsis and rice improved the tolerance and translocation of Cd, Zn, and Mn [31,32].…”

Efficiency of Pb, Zn, Cd, and Mn Removal from Karst Water by Eichhornia crassipes

“…The removal of Pb, Zn, Cd, and Mn by Eichhornia crassipes was highest at the initial concentrations of 1 mg/L, 2 mg/L, 0.02 mg/L, and 0.2 mg/L, respectively. The plants exhibited a certain tolerance to heavy metals; however, they became withered, yellow, and necrotic when the concentrations of heavy metals in the water exceeded the plant’s maximum tolerated concentration to heavy metals [ 41 , 42 ]. Zhou et al [ 43 ] proved that the initial concentrations of heavy metals in an aqueous solution had a significant effect on the removal efficiency of Eichhornia crassipes ; i.e., high concentrations of heavy metals required more active absorption sites for removal.…”

Physiological and Gene Expression Responses of Six Annual Ryegrass Cultivars to Cobalt, Lead, and Nickel Stresses

“…The cell number regulator (CNR) proteins belong to the placenta-specific 8 family, and their role is to regulate cell number and fruit size. However, TaCNR2, TaCNR5, and TuCNR10 are involved in the accumulation and translocation of Cd 2+ , Zn 2+ , and Mn 2+ in the roots of wheat [42,43]. In this study, we detected higher transcript levels of LmCNR1, LmCNR2, and LmCNR13 in the roots of Lm1 treated with heavy metals, but they were down-regulated in shoots, implying that they do not participate in Co 2+ , Pb 2+ , and Ni 2+ translocation.…”