Immunofluorescence localisation of Banana bunchy top virus (family Nanoviridae) within the aphid vector, Pentalonia nigronervosa, suggests a virus tropism distinct from aphid-transmitted luteoviruses

We have applied immunocapture PCR and developed an immunofluorescence assay to specifically detect Banana bunchy top virus (BBTV; family Nanoviridae, genus Babuvirus) within its aphid vector, Pentalonia nigronervosa (Hemiptera, Aphididae). BBTV was localised using either monoclonal or polyclonal antibodies into the anterior midgut (stomach) and into specific cells forming the principal salivary glands. These results suggest a distinct path of virus translocation that likely differs from the one described for aphid-transmitted luteovirus, which enter hemocoels through the hindguts and posterior midguts and that penetrate the accessory salivary glands of their competent vectors. To our understanding, this is the first work analysing the localisation of a virus member of the family Nanoviridae within an aphid vector.