Yeast two-hybrid (Y2H) screening of BnaMPK interaction partners. The yeast strain AH109 harboring the indicated plasmid combinations was grown on either the nonselective (SD-LT) or selective (SD-LTHA) media, followed by X-Gal staining. Control tests were BnaMPK-pGBKT7 with empty pGADT7 vectors. Decreasing cell densities in the dilution series are illustrated by narrowing triangles. The protein interaction pairs are (A) BnaMPK1/2 with BnaWRKY53 and BnaMPK1/2 with BnaMKK9; (B) BnaMPK3/6 with BnaWRKY26 and BnaMKK4/5; (C) BnaWRKY20 with BnaMPK3/6/9; (D) BnaMPK3 with BnaMKK2, BnaMPK3/6 with BnaMKK1; (E) BnaMPK5/9/19/20 with BnaMKK9.