Rose (Rosa spp.) is one of the most famous ornamental plants in the world, and its commodity value largely depends on its flower color. The color of roses mainly depends on the composition and state of anthocyanins, and the vacuolar pH value is an important factor affecting the stability and state of anthocyanins. The vacuolar sodium/proton antiporters (NHXs) play important roles in the maintenance of cellular ion homeostasis and petal vacuolar pH. However, the NHX functions related to rose flower coloration remain relatively uncharacterized. In this study, we cloned and characterized the vacuolar pH-related gene RcNHX2, which encoded a vesicular cation/H