Abstract：MYB transcription factor is one of the largest family of transcription factors in plants which play impotant roles in regulation of plant growth and development, and response to many environmental stimuli. In this study, a gene named CiMYBJ2 (GenBank accession No.KJ937783) was cloned by RACE technique from Caragana intermedia and its expression level along with the promoter was analysed. The full-length cDNA of CiMYBJ2 was 1 368 bp with the 3'UTR of 196 bp and the 5'UTR of 203 bp. The ORF of CiMYBJ2 was 969 bp, encoding a protein of 322 amino acids which was hydrophilia. The full-length gDNA was 1 285 bp, including two introns and three exons. The expression pattern of CiMYBJ2 analysed by qRT-PCR showed that it was altered by heat, dehydration, NaCl and drought treatments. After heat treatment, the expression of CiMYBJ2 decreased at 1 and 3 h, and then maintained a lower level expression. the change of gene expression at different time points was extremely significant compared with the 0 h (P＜0.01). After dehydration treatment for 1 h, the expression of CiMYBJ2 increased shortly, and then gradually decreased at 3 h, and the expression difference was not significant compared with the 0 h (P＞0.05). After 8 h , the expression of the gene showed extremely significant comapred with that of the 0 h (P＜0.01), and the expression level of the gene at 24 h reached only half of that at 0 h (P＜0.05). Under NaCl treatment, the transcript level of CiMYBJ2 began to increase after 1 h, and reached the maximum at 3 h. After that the overall trend kept downward, the expression dropped to the lowest level at 8 h, and expression of the gene was extremely significant at different time points except for 12 h (P＜0.01). After drought treatment of 6 d, the expression of CiMYBJ2 increased slightly, and dropped significanly after compared with 0 d (P＜0.01), reached the minimum expression at 15 d. The promoter sequence of CiMYBJ2 with 873 bp in length was obtained by genome walking technique and many abiotic stress-related cis-elements were found. These results indicated that CiMYBJ2 might be involved in response of C. intermedia to abiotic stresses. The research results provide a basis for the further study of gene function and expression regulation.
