Functional profiling of EcaICE1 transcription factor gene from Eucalyptus camaldulensis involved in cold response in tobacco plants

A full-length cDNA designated as the EcaICE1 gene was isolated from Eucalyptus camaldulensis. The EcaICE1 gene was predicted to encode a MYC-like protein of 523 amino acids presenting a considerable degree of homology to currently identified plant inducer of CBF expression 1 (ICE1) proteins. RT-PCR assays indicated that EcaICE1 gene was expressed in a constitutive pattern in intact E. camaldulensis plants or the cold-treated (4 °C) plantlets. Strikingly, over-expression of the EcaICE1 gene in transgenic tobacco plants could enhance the tolerance to cold stress. While over-expression of the EcaICE1 gene resulted in a profound change of transcript level of C-repeat Binding Factor 1 (CBF1), CBF3 and group 2 LEA protein NtERD10C genes in transgenic tobacco plants. Further analysis revealed that EcaICE1 could function as a transcription activator in planta. Briefly, our results strongly suggest that the EcaICE1 gene is involved in the plant defense responses to low temperature.