Mechanisms of transcytosis across the Spodoptera frugiperda midgut

It is well established that certain proteins are able to move from the insect gut into the hemocoel by unknown mechanisms. Recently, the ability of the plant lectin, Galanthus nivalis agglutinin (GNA) and the coat protein of an aphid-transmitted plant virus to carry a neurotoxin from the gut into the insect hemocoel, has been demonstrated providing a potential new strategy for production of insect resistant transgenic plants. To further investigate protein movement across the insect gut, we utilized an Ussing chamber to compare the efficiencies and mechanisms of transport across the gut of the fall armyworm, Spodoptera frugiperda. The transport efficiencies of selected proteins across the gut epithelium were assessed by protein conjugation with – and detection of - fluorescein isothiocyanate, or eGFP. The epithelial cell types involved were investigated by fluorescence microscopy of excised midgut tissue. The mechanisms involved with movement of proteins across the gut were investigated through the introduction of inhibitors into the Ussing chamber.  We aim to increase fundamental understanding of transcellular transport in the insect gut toward development of new strategies for insect pest management.