Abstract: Nine transgenic plants of Malus robusta were confirmed by Southern blot analysis. The results indicated that one to three copies of the transgene were integrated into the plant genomes respectively, were hydroponically The half fix quantify RT-PCR were carried out to identify transcription of LeIRT2 gene, six carrying one copy of the transgene were successful transcript. Planted to test their efficiency to iron-deficiency, and the tolerance was only found in the transgenic plant4 and 5 with single copy. The rate of root H+ excretion increased in transgenic lines and were substantially higher than those of control. The Fe、Mn、Zn content of leaves and roots of the transgenic lines and non-transgenic plants under the hydroponic experiment in iron-deficient full-strength solution medium with NaFeEDTA 1.00×10-6 mol/L was determined. The total Fe content of the transgenic ling roots and the activated Fe content of the transgenic leaves were notably increased. The Zn content of the transgenic line leaves and roots were notably increased too, but the Mn content was failed to increase. Using LeIRT2 gene from plasmid as the probe, the expression of LeIRT2 in the transgenic malus robusta during iron deficiency was investigated with tissue printing mRNA Northern hybridization. Strong hybridization signals were observed in the leaves and roots of the transgenic malus robusta which had been exposed to iron stress for 5 days.

Key words: Malus robusta, LeIRT2, Tolerance to iron-deficiency