Seed storage proteins are the main repository for nitrogen and thus provide nutrient source for embryo germination,humans and livestock feeding.Prolamins,the major cereal seed storage proteins,accumulate and sequester in ER lumen,and directly form protein bodies (PBs).The content and composition of prolamins are key determinants of grain protein quality and texture related traits.Meanwhile,the PB-inducing fusion system is an efficient approach to produce therapeutic and industrially important proteins in plants.However,the protein composition of the native PB and the detailed mechanism underlying its formation are still elusive.Here,we develop a novel method for the isolation of highly purified and intact PBs from maize (Zea mays) endosperm.