Figure 5. FhGL3L and FhTT8L Physically Interacted with Different Arabidopsis MYBs in Plant Cells.

(A) Schematic diagram of Arabidopsis protoplasts transfection assays. Relative GUS activities in Arabidopsis mesophyll protoplasts co-transfected with a GUS reporter gene and constructs expressing GAL4 DNA-binding domain (GD) fusion were shown in the top program. Expression of GUS gene occurred if the gene fused to GD had the activating ability. The bottom diagram were the constructs used in detecting the interaction between two proteins. A protein with no or low activation ability was fused to GD. Activation of report only occurred when another protein with activating ability interacted with the GD fusing protein. (B) Activation abilities of bHLHs. Only AtGL3 showed high activating ability while others not. (C) FhGL3L physically interact with AtPAP1, AtGL1 and AtTT2. (D–F) FhTT8L physically interacted with AtPAP1 and AtTT2 but not with AtGL1. Activation of GAL4 by the respective constructs was determined by measuring beta-glucuronidase activity. Reporter and effector gene plasmids were co-transfected into protoplasts isolated from Arabidopsis rosette leaves. Protoplasts were incubated in darkness for 20–22 h after transfection, and then GUS activity was measured. Data represented the mean ± SD of three replicates. T-test was used to analysis the significant defference (*P < 0.05; **p < 0.01). All tests were computed using SPSS(ver.17.0).