Functional Identification And Subcellular Localization Of MxIrt Transporter Of Iron-efficient Genotype In The Genus Malus

The expression of IRT(iron-regulated transporter )was enchanced in the Malus xiaojinensis Cheng et Jiang under iron-deficient conditions. Based it .this paper discussed its function and subcellular localization.Firstly, an expression vector including the IRT gene was constructed, then transformed into the yeast mutant DDY4 defective for iron transporting gene fet3 and fet4on the selection medium without iron, the expression of IRT could complement the growth of the mutant, but the mutant not including the IRT gene could not grow well. This result implied that the IRT protein might be an iron transporter.According to above result, if the IRT gene was expressed, the iron content in the positive transformer with IRT should be higher than that in the mutant, so the iron content was measured in different yeast strains (including wild-typed, transformer with IRT and mutant). The data indicated that the iron content in the transformer was indeedly highest in all of strains.IRT protein was expective an integral membrane. In order to observe its subcellular localization , an expression vector including IRT gene and GFP (green fluorescent protein) was constructed and then transformed into the yeast strain by LiAc method. At last, green fluorescent could be emitted by fused protein with IRT::GFP under the fluoroscope and laser confocal microscope. It was deduced that MxIRT should be localized in the plasma membrane.