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

• Main Authors: Feng Xiao-Ming, Zhao Qiang, Zhao Ling-Ling, Qiao Yu, Xie Xing-Bin, Li Hui-Feng, Yao Yu-Xin, You Chun-Xiang, Hao Yu-Jin
• Format: Article
• Language: English
• Published: BMC 2012-02-01
• Series: BMC Plant Biology
• Online Access: http://www.biomedcentral.com/1471-2229/12/22

<p>Abstract</p> <p>Background</p> <p>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 <it>Arabidopsis</it>, little is known about the transcription factors involved in the cold stress response in apple.</p> <p>Results</p> <p>Here, we show that the apple bHLH (basic helix-loop-helix) gene <it>MdCIbHLH1 </it>(<it>Cold-Induced bHLH1</it>), 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 <it>AtCBF3 </it>promoter, and <it>MdCIbHLH1 </it>overexpression enhanced cold tolerance in transgenic <it>Arabidopsis</it>. In addition, the MdCIbHLH1 protein bound to the promoters of <it>MdCBF2 </it>and favorably contributed to cold tolerance in transgenic apple plants by upregulating the expression of <it>MdCBF2 </it>through the CBF (C-repeat-binding factor) pathway. Our findings indicate that MdCIbHLH1 functions in stress tolerance in different species. For example, ectopic <it>MdCIbHLH1 </it>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.</p> <p>Conclusions</p> <p>Based on these findings, <it>MdCIbHLH1 </it>encodes a transcription factor that is important for the cold tolerance response in apple.</p>