Abstract: 【Objective】This study was carried out in order to better understanding the mechanism of nuclear-cytoplasmic interactions in OguCMS Chinese cabbage pak-choi （Brassica campestris L. ssp. chinensis Makino var. communis Tsen et Lee cv. Aijiaohuang）.【Method】Expreesion profiling was performed using cDNA-AFLP technology on floral buds of OguCMS lines and maintainers in Chinese cabbage pak-choi. A differentially expressed cDNA fragment was obtained，which was unexpressed in early-stage buds of maintainers, but expressed steabilely in OguCMS floral buds. The full cDNA, designated as BcBHLogu（GenBank accession numbers:EF127860）, was obtained by RACE. 【Results】 BcBHLogu coded 122 amino acids , contained a bHLH domain, and shared high homology with AtBHLH060. The phyogenetic analysis indicted BcBHLogu and AtBHLHs060/048 were orthologs genes. Its function was similar to BEEs1/2/3，which were three redundant Brassinostreriod early response genes.【Conclusion】BcBHLHogu was predicted a novel bHLH transcription factor in Chinese cabbage, which gene appears to be involved in developmental signaling events for floral processes and had a function related to Brassinosteriods signaling response.

Key words: Chinese cabbage (Brassica campestris ssp. Chinensis), bHLH transcription factor, Cloning, Characterization