Bioinformatics Analysis Of Apple ZIP Gene Family And Functional Analysis Of MdZIP10 Gene

Zinc is essential micronutrients for plants,which participates in some physiological and biochemical processes to promote plants growth and development.Zn deficiency can affect plant growth,but excess levels cause phytotoxicity.Therefore,it is crucial to strictly control the content and maintain the balance of metal ions in plants.Recently,the continuous discovery of metal ion transporters has laid the foundation for the study of metal ion absorption,intracellular transport,and intracellular localization.Zinc deficiency is common in apple production and affects fruit yield and quality.However,the absorption and transport mechanisms of zinc in apples are still unclear.In the present study,apple rootstock cultivar(Malus hupehensis Rehd.)were used as materials,and based on apple genome sequenced in2010,we performed bioinformatics analysis on the apple ZIP gene family,and the expression pattern of the apple ZIP gene under zinc-iron stress conditions was analyzed.Md ZIP10 were cloned from apple and its functions were analyzed in Arabidopsis.The main results were as follows:(1)BLAST and HMM were used to identify the ZIP genes family in apple,and 18 candidates were confirmed as MdZIP members in the apple genome.The 18 MdZIP proteins were named MdZIP1 to MdZIP18 based on their chromosomal locations.MdZIPs family was divided into four groups.MdZIP8,MdZIP7,MZIP12,MdZIP11,MdZIP3,MdZIP13,and MdZIP2 belonged to group I.MdZIP6,MdZIP18,MdZIP16,and MdZIP15 were in second II.MdZIP1,MdZIP14,MdZIP5,and MdZIP4 were in group III,and MdZIP9,MdZIP10,and MdZIP17 belonged to group IV.We also surveyed gene structures of the MdZIP genes.The result showed that among the exon-intron containing ZIP genes,the number of introns and exons in their open reading frame(ORF)ranged from 1 to 11.Furthermore,members of the MdZIP family in a same cluster also exhibit similar gene structures.The 18 MdZIP genes could be mapped to the eight apple chromosomes.The location of 18 genes on chromosomes are not the same,most MdZIP genes are mapped on chromosome 3,5,and 8.The rest aremapped on chromosomes 4,11,12,13,and 15.MdZIPs genes expression patterns in the roots and leaves of apple exposed to Zn and Fe deficiencies were analyzed using qRT-PCR.The results showed that although the MdZIP genes were express in different environments,they exhibited different expression patterns.(2)MdZIP10 was cloned,and the GFP coding sequence was in-frame fused to the predicted start codon of MdZIP10 for determining MdZIP10 subcellular localization,the result showed that it colocalized in the plasma membrane.(3)Overexpression of MdZIP10 increased the Zn content of Arabidopsis,and enhanced iron storage in roots and leaves,the fluorescence signals in seedlings and apical and lateral roots of transgenic plants were considerably stronger than in the wild-type.Under conditions of deficient Zn and Fe,the symptoms were relieved in MdZIP10 transgenic plants.The expression of genes related to Fe and Zn uptake and transport was induced in MdZIP10 transgenic plants,and the uptake and transport of endogenous Fe and Zn were stimulated.