Objective  To investigate the molecular mechanism of flavonol synthase (FLS) gene in peony flower (Paeonia lactiflora) color formation.

Method  We cloned PlFLS gene and carried out bioinformatics analysis. The over-expression vector of PlFLS gene was constructed and transformed as heterologous gene into Arabidopsis by floral-dip method with recombinant agrobacterium transformants.

Result  The bioinformatics analysis results suggested that the amino acid sequence of PlFLS gene was highly similar with Camellia sinensis, and there were two structure domains but no potential signal peptide. The tertiary structure prediction of PlFLS protein showed that there was a 2-oxoglutaric acid ligand connecting with several peptide chains. Transgenic Arabidopsis plants expressing homologous PlFLS gene were obtained successfully. GUS staining and PCR detection confirmed the integration of PlFLS gene into Arabidopsis genome, and qRT-PCR analysis showed PlFLS gene was expressed at significantly higher level in transgenic lines compared with wide type (P<0.05). Through HPLC detection, the anthoxanthin content in transgenic plants significantly increased compared with wide type (P<0.05).

Conclusion  PlFLS gene has been transformed into Arabidopsis successfully and it plays an important role in regulating the synthesis of flavonoids.