Function of chalcone reductase gene CHR1 in soybean.

To verify the function of chalcone reductase gene (CHR1) in soybean Daidzein synthesis, CHR1 gene in soybean was cloned, and an RNAi expression vector pCPB-CHR1-RNAi was constructed. Four transformed plants in T0 generation and thirteen transformed plants in T1 generation of soybean "Jinong28" were obtained by agrobacterium-mediated genetic transformation, in which transcriptions of CHR1 gene were depressed. Southern blotting showed the functional fragment of pCPB-CHR1-RNAi was integrated into the genome of recipient soybean in the form of a single copy. Detection of the transcription of CHR1 gene using quantitative real-time PCR (qRT-PCR) showed that the expression of CHR1 gene in transformed plants decreased 60%-99% compared to the recipient soybean, while the content of isoliquiritigenin, the precursors of daidzein, decreased 38.7%. These results indicate that RNA interference can suppress the transcription of CHR1 gene expression successfully.