Figure 1 Plasmid maps (A) pCAMBIA1300-NLuc (pNL); (B) pCAMBIA1300-CLuc (pCL); (C) pCAMBIA1300-HA-NLuc (pHNL); (D) pCAMBIA1300-CCLuc (pCCL). All the vectors have a framework of pCAMBIA1300 and allow expression of the target genes with a C-terminal NLuc fusion and N-terminal or C-terminal CLuc fusion. Unique sites are shown in sequence. MCS: Multiple cloning sites; L: Linker sequence; RBS: Transcription terminator; ATG: Translation initiation codon; TGA: Translation stop codon; HA: Tag protein

Figure 2 Schematic diagram of the Luciferase Complementation Assay (A) Select fully expanded young leaves of Nicotiana benthamiana (four-week old) for Agrobacterium injection, observe after 24-48 h (Bar=2 cm); (B) Cut the infiltrated tobacco leaves and put them into the petri dish (Bar=1 cm); (C) Use CCD imaging system to detect the luminescence of the complete tobacco leaves and captured the pictures; (D) Select infiltrated leaves for punch (Bar=1 cm); (E) Punch tobacco leaf discs of 0.6 cm in diameter from infiltrated leaf areas by a cork borer and place leaf discs in a 96-well plate containing 200 μL sterile water in each well; (F) Use luminometer to scan the fluorescence intensity of the tobacco leaves. The circles show the injection sites of Agrobacterium.

Figure 3 An example of dynamic OsXLG2-OsBIK1 interactions Four-week old Nicotiana benthamiana leaves co-infiltrated with Agrobacterium expressing CLuc-OsXLG2 and OsBIK1-NLuc. CLuc-OsPPI and OsBIK1-NLuc are used as negative control (unpublished). (A) The luminescence images were captured using a CCD imaging system (Bar=2 cm); (B) The luciferase activity measurement using a luminometer, the error bars represent the standard deviation from the mean (n=8); (C) Western blot analysis of the expressed proteins of CLuc- and NLuc- fusions, the fusions are detected using anti-luciferase and anti-CLuc antibodies, respectively.