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Open Access Research article

The cold-induced basic helix-loop-helix transcription factor gene MdCIbHLH1 encodes an ICE-like protein in apple

Xiao-Ming Feng1, Qiang Zhao1, Ling-Ling Zhao2, Yu Qiao1, Xing-Bin Xie1, Hui-Feng Li3, Yu-Xin Yao1, Chun-Xiang You1 and Yu-Jin Hao1*

Author Affiliations

1 The State Key Laboratory of Crop Biology; National Research Center for Apple Engineering and Technology; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China

2 Yantai Academy of Agricultural Science, Yantai, Shandong 265500, China

3 Shandong Institute of Pomology, Tai-An, Shandong 271000, China

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BMC Plant Biology 2012, 12:22  doi:10.1186/1471-2229-12-22

Published: 15 February 2012

Abstract

Background

Plant growth is greatly affected by low temperatures, and the expression of a number of genes is induced by cold stress. Although many genes in the cold signaling pathway have been identified in Arabidopsis, little is known about the transcription factors involved in the cold stress response in apple.

Results

Here, we show that the apple bHLH (basic helix-loop-helix) gene MdCIbHLH1 (Cold-Induced bHLH1), which encodes an ICE-like protein, was noticeably induced in response to cold stress. The MdCIbHLH1 protein specifically bound to the MYC recognition sequences in the AtCBF3 promoter, and MdCIbHLH1 overexpression enhanced cold tolerance in transgenic Arabidopsis. In addition, the MdCIbHLH1 protein bound to the promoters of MdCBF2 and favorably contributed to cold tolerance in transgenic apple plants by upregulating the expression of MdCBF2 through the CBF (C-repeat-binding factor) pathway. Our findings indicate that MdCIbHLH1 functions in stress tolerance in different species. For example, ectopic MdCIbHLH1 expression conferred enhanced chilling tolerance in transgenic tobacco. Finally, we observed that cold induces the degradation of the MdCIbHLH1 protein in apple and that this degradation was potentially mediated by ubiquitination and sumoylation.

Conclusions

Based on these findings, MdCIbHLH1 encodes a transcription factor that is important for the cold tolerance response in apple.