Guan MeiYan, Chen MingXue, Cao ZhenZhen
Rice Product Quality Supervision and Inspection Center, China National Rice Research Institute, Hangzhou 310006, China.
Rice Product Quality Supervision and Inspection Center, China National Rice Research Institute, Hangzhou 310006, China.
Ecotoxicol Environ Saf. 2021 Apr 28;218:112269. doi: 10.1016/j.ecoenv.2021.112269.
Management of nitrogen fertilizer is a good strategy for controlling cadmium (Cd) accumulation in plants. Some progress has already been made but much remains to be done. Here, we show that mutants with loss of function of nitrate transporter1.1 (NRT1.1) or nitrate transporter2.1 (NRT2.1) had lower Cd concentrations than wild-type plants under low-nitrate conditions. However, this was eliminated when plants were cultivated in nitrate-free medium or supplied with Cd and nitrate alternately. These findings indicate that inhibition of NRT1.1 or NRT2.1 activity reduces Cd accumulation in plants, and depends on the presence of nitrate. The results showing that nrt2.1-2 mutants had the lowest Cd concentrations compared with Col-0, nrt1.1 and nrt2.4 plants, proves that NRT2.1 is the major contributor to Cd uptake controlled by nitrate high-affinity transporters. NRT2.1 acts as the major contributor to nitrate uptake under Cd stress in low-nitrate conditions, and contributes about 50% to nitrate uptake, while NRT1.1 contributes only 10%, and little is known regarding the role of NRT2.2 and NRT2.4 on nitrate uptake in medium with 200 μM nitrate. Positive correlations between nitrate uptake and Cd concentration in plants were also observed. Collectively, NRT2.1 acts as the major contributor to Cd uptake by controlling nitrate uptake in nitrate high-affinity systems.
氮肥管理是控制植物中镉（Cd）积累的一种有效策略。目前已经取得了一些进展，但仍有许多工作要做。在此，我们表明，在低硝酸盐条件下，硝酸盐转运蛋白1.1（NRT1.1）或硝酸盐转运蛋白2.1（NRT2.1）功能丧失的突变体的镉浓度低于野生型植物。然而，当植物在无硝酸盐培养基中培养或交替供应镉和硝酸盐时，这种差异就消失了。这些发现表明，抑制NRT1.1或NRT2.1的活性可减少植物中的镉积累，且这取决于硝酸盐的存在。结果表明，与Col-0、nrt1.1和nrt2.4植物相比，nrt2.1-2突变体的镉浓度最低，这证明NRT2.1是硝酸盐高亲和力转运蛋白控制镉吸收的主要贡献者。在低硝酸盐条件下的镉胁迫下，NRT2.1是硝酸盐吸收的主要贡献者，约占硝酸盐吸收的50%，而NRT1.1仅占10%，关于NRT2.2和NRT2.4在200μM硝酸盐培养基中对硝酸盐吸收的作用知之甚少。还观察到植物中硝酸盐吸收与镉浓度之间呈正相关。总的来说，NRT2.1通过控制硝酸盐高亲和力系统中的硝酸盐吸收，成为镉吸收的主要贡献者。
