Abstract：Malus xiaojinensis is an iron-efficient apple genotype. Through the analysis of apple’s EST, a 791 bp YSL (yellow stripe 1-like protein) gene fragments were obtained, and their specific primers were designed to obtainYSL gene fragment in Malus xiaojinensis . The complete 3' sequence of YSL gene was obtained by RACE method, which were composed of 1 114 nucleotides. The predicted amino-acid sequence included 7 putative membrane-spanning domains and its homology with AtYSL1 was up to 74%, and was named as MxYSL1. The results of semi-quantitative RT-PCR and Northern blotting analysis showed that MxYSL1 was expressed in all organs of M. xiaojinensis. The expressions were down-regulated in roots, stems and mature leaves with Fe deficiency treatments(EDTA-NaFe,4 μmol/L), but up-regulated with Fe excess treatments(EDTA-NaFe,320 μmol/L). The young leaves had opposite expression model.
