Functional Identification Of Zinc Transporter ZIP11 In Arabidopsis Thaliana

The zinc(Zn)/iron(Fe)element is an essential trace element for the life activities of organisms,lack or excess will affect the growth and development of organisms,so the level of these elements must be maintained in a normal range.For this reason,organisms have evolved regulatory mechanisms that can maintain metal homeostasis,such as ZIP family,CDF family,PCR family,VIT family,YSL family,NRAMP family,etc,among which ZIP family is considered as the main Zn/Fe transportor.The 15 members of the ZIP family in Arabidopsis thaliana have been extensively studied,but the functions and mechanisms still unclear.In this study,the Zn/Fe transport capacity and its subcellular localization of AtZIP11 in Arabidopsis thaliana were studied,with a view to revealing the mechanism of AtZIP11 and laying a foundation for further study of AtZIP11 and cultivation of reasonable Zn/Fe content plants.The results are as follows:(1)AtZIP11 is a Zn²⁺transporter.Complementary yeast zinc or iron transport deficient mutant,the results showed that AtZIP11 could restore the growth of low zinc sensitive yeast mutant ZHY3 on low zinc medium.AtZIP11 Non-transmembrane polypeptide fragments were titrated with Zn²⁺,and 6 polypeptide fragments of AtZIP11 were found to bind to Zn²⁺,the binding site is histidine.(2)AtZIP11 can bind to Fe²⁺,but does not participate in Fe²⁺transport.Complementary yeast zinc or iron transport deficient mutant,the results showed that AtZIP11 could not restore the growth of low iron sensitive yeast mutant DEY1453 on low iron medium.The non-transmembrane domain peptides of AtZIP11 were titrated by Fe²⁺,and two peptides were found to bind to Fe²⁺,the binding site is lysine.(3)AtZIP11 is located in mitochondria.(4)AtZIP11 is a Zn²⁺absorption and transport protein.GUS staining experiment showed that AtZIP11 was expressed in the vascular bundle of Arabidopsis thaliana at seedling stage,but not in the vascular bundle at mature stage,suggesting that AtZIP11 is involved in the transport of Zn²⁺in Arabidopsis at seedling stage.The expression of AtZIP11 in root hair indicated that AtZIP11 was involved in the absorption of Zn²⁺in Arabidopsis roots.