Aquaporins facilitate the transport of water and small neutral solutes across cell membranes. This aquaporin may function in transporting small molecules across the peribacteroid membranes. During nodulation in legume roots after Rhizobium infection. Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro-Ala (NPA). Belongs to the MIP/aquaporin (TC 1.A.8) family. NIP (TC 1.A.8.12) subfamily.