About 230bp of DHAR partial DNA segments was obtained from Subtractive hybridization library, which is highly similar with the nucleotide sequence of DNA encoding DHAR gene, the Subtractive hybridization library was constructed by dwarf mutant and wild-type parent. A full-length cDNA sequence of the gene named BnDHAR was cloned by homologous cloning from Brassica napus. BnDHAR was fully consistent with nucleotide sequence of the gene in the published Brassica napus genome. There were no difference in the DHAR full-length cDNA sequence between dwarf mutant and its wild-type parent. We used qRT-PCR technology analysised the BnDHAR gene expression in different organizations at various periods of Brassica napus , the results showed that: BnDHAR gene expression in the wild-type Brassica napus leaves is the highest approximately 5 times in the dwarf mutant at the seeding stage, and extremely low expression in roots and stems, dwarf mutant and tall wild-type didn’t have any significant difference. Under the high temperature stress, the expression of the BnDHAR gene increased; under the salt stress, BnDHAR reached the highest expression after dealing with 9h, then showed a downward trend; under the drought stress, the expression reached the highest after 12 hours, also showed a downward trend after the first rise. In summary, the BnDHAR gene exhibited a tissue specific expression in Brassica napus and also related with growth and abiotic stress response.
