In vivo BiFC analysis of BnaMPK1 interacting proteins BnaMKK9 and BnaWRKY53 in co-transformed in N. benthamiana leaf epidermal cells. BnaMPK1 was fused to N- terminal while (A) BnaMKK9 and (B) BnaWRKY53 were fused to C-terminal halves of YFP, individually. (C) A vector control with no protein fusion to the C-terminal YFP is also shown. The fluorescence of YFP was observed by confocal laser microscopy. Bar = 50 μm.