Abstract: A bHLH transcription factor was found from apple（Malus × domestica Borkh.）induced by low temperature. To understand sequence characteristics of the gene，bioinformatics analysis was carried out. Furthermore，the gene expression patterns of the laminated apple seeds and lateral flower buds were analyzed during the period of dormancy and release by semi RT-PCR and real-time PCR. On the basis of secondary structure prediction，the results showed that MdCIbHIH protein was mainly α-helix and random coil，the contents of β-sheet and extended strand were less，including random coil 310（58.38%），α-helix 145（27.31%）and β-sheet 19（3.58%），respectively，extending chain 57（10.73%）. qRT-PCR analysis showed that the expression patterns of MdCIbHLH1 was similar in the laminated apple seeds and lateral flower buds during the period of dormancy-release. The MdCIbHLH1 expression levels highly accumulated in dormant buds or apple seeds and were gradually down-regulated during the period of the release of dormancy. These results indicated that MdCIbHLH1 might play an important role in the regulation of dormancy-release in apple seeds and buds.

Key words: apple, MdCIbHLH1, dormancy, expression analysis