The identification of novel PMADS3 interacting proteins indicates a role in post-transcriptional control

• Subcellular localization and interaction assays of PMADS3 and other proteins were performed in living plant cells.
• Novel PMADS3-interacting proteins were explored by the screening of a yeast two-hybrid cDNA library.
• Two novel genes, PheIF3f and PhAGO10, were subcellular localized, and confirmed to interact with PMADS3.
• Potential function of PMADS3 in post-transcriptional control was implied.

PMADS3, a known MADS-box transcriptional factor and a C-class gene for floral development, plays dual roles in controlling the identity of inner floral organs and the termination of flower meristems in petunia. In this study, it was confirmed by bimolecular fluorescence complementation (BiFC) assays that the PMADS3 protein can interact individually with E-class proteins FBP2, FBP5, FBP9 and PMADS12. A yeast two-hybrid cDNA library was screened using the entire PMADS3 as bait, and this identified further potential interaction candidates. Two novel genes, PheIF3f and PhAGO10, were isolated, and suggested to regulate mRNA and translational processes according to the analysis of protein functional domains and subcellular localization predictions. Notably, the PhAGO10 protein belongs to the Argonaute family, members of which are major players in small-RNA-guided gene silencing processes via mRNA cleavage or translational inhibition. The results of yeast two-hybrid and BiFC assays indicated that PheIF3f and PhAGO10 could interact with PMADS3. Our findings indicate that the C-class gene PMADS3 potentially participates in post-transcriptional control, as well as transcriptional regulation.