Abstract: The fate of the flowering signal integrators is determined by Flowering Locus C（FLC）and SHOTR VEGETATIVE PHASE（SVP），which probably directly interact with each other to regulate flowering. For further study on mechanism and reagent control of the interactions between the two transcription factors，the protein interactions in vitro were testified in Brassica juncea Coss.（mustard）variety‘QJ’. In the present study，the coding sequences of FLC and SVP were amplified，and then inserted into the expression vector pET43.1a to construct the recombinant plasmids pET43.1a-FLC and pET43.1a-SVP. After transformation to E. coli（BL21），the expression of recombinant proteins were detected via SDS-PAGE. With co-immunoprecipitation and characteristic of 6 × His tag in fusion protein of pET43.1a-FLC and pET43.1a-SVP which could combine with Ni+，a new method was put forward to detecting the interactions between FLC and SVP proteins. Using this method，the interactions were analyzed via SDS-PAGE. The results showed that FLC and SVP could act with each other to combine and form a complex. This research provides theoretical and technical bases for analyzing the mechanism of interactions between FLC and SVP，for further probing into interactions between FLC，SVP and downstream targets of flowering signal integrators.

Key words: Brassica juncea Coss., FLC, SVP, protein interaction