Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu, China.
PLoS One. 2018 Jul 23;13(7):e0199081. doi: 10.1371/journal.pone.0199081. eCollection 2018.
Copper (Cu) is an essential micronutrient for plant growth and development; Cu homeostasis in plant is maintained by the important functions of Ctr/COPT-type Cu transporters. Although the COPT genes have been identified in Arabidopsis thaliana and rice, little is known about Cu transporters in maize. In this study, three-members of putative maize Cu transporters (ZmCOPT 1, 2 and 3) are identified. ZmCOPT genes have expression in all of the tested tissues, including roots, stems, leaves and flowers (male and female), and their expression levels vary responding to stress due to Cu-deficiency and excess. Functional complementation and overexpression together with Cu uptake measurements in ZmCOPTs-transformed ctr1⊿ctr2⊿mutant strain or the wild type strain of Saccharomyces cerevisiae show that the three ZmCOPT members possess the ability to be Cu transporters. Among these, ZmCOPT1 and ZmCOPT2 have high-affinity while ZmCOPT3 has low-affinity. In addition, ZmCOPT2 tend to specifically transport Cu (I) but no other bivalent metal ions.
铜（Cu）是植物生长和发育所必需的微量元素；植物中的铜稳态是通过 Ctr/COPT 型铜转运蛋白的重要功能来维持的。虽然拟南芥和水稻中的 COPT 基因已经被鉴定出来，但关于玉米中的铜转运蛋白知之甚少。在这项研究中，鉴定了三个玉米铜转运蛋白（ZmCOPT1、2 和 3）的假定成员。ZmCOPT 基因在所有测试的组织中都有表达，包括根、茎、叶和花（雄性和雌性），并且它们的表达水平因 Cu 缺乏和过量引起的胁迫而变化。功能互补和过表达以及在 ZmCOPT 转化的 ctr1⊿ctr2⊿突变体或酿酒酵母野生型菌株中的 Cu 摄取测量表明，这三个 ZmCOPT 成员具有作为 Cu 转运蛋白的能力。其中，ZmCOPT1 和 ZmCOPT2 具有高亲和力，而 ZmCOPT3 具有低亲和力。此外，ZmCOPT2 倾向于特异性运输 Cu（I）而不是其他二价金属离子。
