Molecular Cloning and Expression Analysis of the Transcription Factor Gene JrCBF from Juglans regia L.

The CBF (C-repeat binding factor) genes are an important family of transcription factors in plants, encoding transcriptional regulators with a variety of functions involved in developmental and physiological processes. In this study, the conserved domain of the CBF gene in Juglans regia L. was cloned using two degenerate primers, and the 5' terminal and 3' terminal of the gene were amplified by using rapid amplification of cDNA ends (RACE) methods. The complete cDNA sequence termed as JrCBF was obtained and the sequence was submitted to GenBank (GenBank accession number JX875914). Sequence analysis showed that the nucleotide sequence of JrCBF was 879 bp, containing an open reading frame (ORF) of 645 bp and encoding a protein with 214 amino acids. The alignment analysis indicated that the predicted protein sequence contained a typical AP2/EREBP DNA-binding domain. Homology analysis showed that the JrCBF protein had 69 and 63% homology with CBF from Betula platyphylla and Malus x domestica, respectively. And its hydrophobicity/hydrophilic, physico-chemical properties, phylogenetic tree, and main functional domains were predicted. Real-time quantitative polymerase chain reaction (Real-Time PCR) analysis was performed for JrCBF treated with a low-temperature of 4 degrees C. The results showed that JrCBF gene expression was increased 2 h after being cold induced and reached a peak after 8 h, and then decreased. JrCBF might play a key role during the development of cold resistant molecular mechanisms in Juglans regia L.