A yeast one-hybrid assay was optimized for screening plant cell factors which could be interacted to a virulence protein of  Agrobacterium tumefaciens (VirE2). In this assay,  a plant cDNA library was used for interaction trap of cDNA clones potentially interact to a fusion protein encoded by a special plasmid termed bait.  As a result, two Arabidopsis thaliana proteins which interacted to the fusion protein were identified in vivo. Screenings on selective media and b-galactosidase assays were confirmed the specific binding of proteins to VirE2 protein and their nuclear import. The cDNA isolated from one of the clones for further analysis.