14-3-3 Proteins Participate in Regulation of Natural Rubber Biosynthesis in Hevea brasiliensis

Abstract

Plant 14-3-3 proteins mediate a wide range of functionally diverse proteins through protein–protein interactions that are typically phosphorylation-dependent. However, the interactions between 14-3-3 proteins and the major regulators of nature rubber (NR) biosynthesis in H. brasiliensis have not been fully elucidated. In this study, we obtained 81 essential client proteins that interacted with H. brasiliensis 14-3-3 proteins (HbGF14s) through yeast two-hybrid (Y2H) screening. These interaction partners were involved in plant signal transduction, metabolism, development, and NR biosynthesis including small rubber particle protein (SRPP), rubber elongation factor (REF), and MYC2, etc. Furthermore, the interaction of HbGF14c and HbSRPP of H. brasiliensis was confirmed in plants through bimolecular fluorescence complementation (BiFC) assays and in vitro with Pull-down assays. Specifically, the RVSSYLP motif was found to mediate the interaction between HbSRPP and HbGF14c. The findings of this study provide a theoretical basis for the elucidation of the molecular regulation mechanism of the 14-3-3 proteins involved in NR biosynthesis, which could be used to enhance the production of rubber trees through genetic improvement.