Abstract: A phytochrome-interacting factor（PIF）gene was isolate from the spur type apple（Malus domestica Borkh.）by using RT-PCR and RACE method，the gene was named MdPIF，containing an open reading frame（2 142 bp）and encoding a protein of 713 amino acid. Sequence analysis indicated that MdPIF shared highly homology with bHLH family protein and the APB domain of phytochrome- interacting. The real-time quantitative PCR analysis showed that MdPIF gene expressed in stem of spur type apple trees during the 20–110 days after flowering. In the same development stage，the MdPIF was lower expression in spur type apple stem than in non-spur type apple. The MdPIF gene was expressed in leaf，stem，flower，fruit and bud of the spur type apple. However，the expression of the gene was different. The relative expression level of MdPIF gene was up to the maximum value in the stem. The research results suggested that the MdPIF gene play an important role during the stem developing of apple.

Key words: apple, spur-type, phytochrome-interacting factor, gene, cloning, expression