Our crop yields are limited by osmotic stresses, which often occur as a result of drought and salinity. There is potential for us to be able to improve crop osmotic stress tolerance by manipulating the function of aquaporins. Aquaporins are membrane intrinsic proteins, which are renowned for functioning as water channels. Our team discovered that a subset of plant aquaporins can switch between functioning as water channels and functioning as channels that are permeable to salt ions. We have identified aquaporin post-translational modifications that function like “molecular switches”, regulating the ion and water channel activity of dual ion:water aquaporins. We are working on translating these discoveries into engineering strategies to increase crop tolerance to salinity and drought, and to advance water filtration technology.