In this study, the interaction between rice 14-3-3 protein and 1-aminocyclopropane carboxylic acid synthase (ACS) was observed in yeast cells using yeast two-hybrid assays. Given the fact that 14-3-3 proteins generally bind to their target proteins in a phosphorylation-dependent manner, a hypothesis regarding the regulatory role of 14-3-3 proteins in the activation of ACS is proposed in which 14-3-3 proteins may bind to the phosphorylated C-terminal tails of ACSs and help them to escape from their fated degradation when ethylene biosynthesis is needed. It is reasonable to believe that 14-3-3 protein may play an important role in regulating ACS activity.