HPt2, HPt7 and HPt9 interact with a subset of B-type RRs in the yeast two-hybrid system. A) X-gal assays of HPt/B-type RR interactions. HPts (HPt2, 7, 9) interactions with B-type RRs (RR12, 13, 14, 15, 16, 19, 21 and 22) as indicated and the corresponding X-gal assay on leucine-tryptophan-histidine lacking medium (−LWH) supplemented with 60 (HPt2) or 20 (HPt7, 9) mM of 3AT. B) ß-Galactosidase activity measurements of HPt/B-type RR interactions. Means ± standard error of three independent replicates of ß-Galactosidase activity measurements are presented for each HPt/B-type RR interaction. The negative control (CT) of each HPt is the interaction background between HPt2, 7 or 9 and the empty vector pGAD. The mean values of HPt/RR interactions were compared to their respective negative control by a t-test and asterisks indicate significant differences: *P < 0.05, **P < 0.01, ***P < 0.001 and NS for not significant. The mean values of interaction between HPts and RR12, 13, 14, 15, 16, 21, and 22 are compared by ANOVA followed by Scheffe test; different letters indicate significant differences (P ≤ 0.05).