To study the functions of bHLH TFs in Brassica napus, five full length cDNA sequences of BnbHLH92 genes are cloned from Brassica napus by the homologous cloning method and named as BnbHLH92-1, BnbHLH92-2, BnbHLH92-3, BnbHLH92-4, BnbHLH92-5, respectively. And the length of the coding region for each gene is 738, 657, 684, 741, 717 bp, respectively. The qRT PCR result shows that BnbHLH92-1 gene is expressed in the root of the bolting stage and flowering stage as well as the two leaves stage, but the other BnbHLH92 genes mainly expressed in the roots of the bolting stage and the flowering stage. The expression of BnbHLH92 genes is significantly affected by abiotic stress, which increases the amount of genes expression. The expression level of five BnbHLH92 genes reach its highest under a low temperature stress for 4, 6, 6, 6 and 6 h, under a high temperature stress for 2, 6, 6, 8 and 4 h, under a salt stress for 6, 6, 24, 24 and 24 h, respectively. The expression of each BnbHLH92 gene is also increased in different degrees under ABA induction. It is found that there is an ABA response element (ABRE) on the promoter sequence of each BnbHLH92 gene.
