In order to explore the expression of HY5 in Brassica napus L., firstly, HY5 and its homologous gene HYH (HY5-Homologous) were predicted by genomic data analysis, and the full-length cDNA sequences of four duplication genes of HY5 (named BnHY5) were cloned. As well as three duplication HYH (named BnHYH) were also cloned. Then, we predicted and analyzed the protein structure of BnHY5 and its chemical properties. The results showed that BnHY5 protein is an unstable and hydrophilic protein, and the main domain is leucine zipper. Finally, BnHY5 duplication gene expression pattern was analyzed by real-time PCR with normal growth conditions and abiotic stress. The results showed that among 4 BnHY5 genes, BnHY5-2 has the highest expression level. BnHY5-1 and BnHY5-2 have no tissue expression differences and the expression level is higher than BnHY5-3, BnHY5-4. BnHY5 gene not only responds to high temperature, low temperature, cadmium, high salt abiotic stress but also participates in ABA and GA3 hormone signal responses, indicating that BnHY5 plays an important role in abiotic stress. In addition, compared with the expression of BnHY5 duplications in normal growth rape, the expression level of BnHY5 duplications under different types of stress treatment changed. The expression ratio of the four genes of BnHY5 has a relationship to different types of stress treatment.
