Immunolocalization of odorant-binding proteins on antennal chemosensilla of the peach aphid Myzus persicae (Sulzer).

The antennal sensilla of Myzus persicae were mapped using scanning and transmission electron microscopy. Placoid sensilla and coeloconic sensilla were found on the 6th segments, whereas 2 types of trichoid sensilla were present all through the length of the antenna. A single sensillum placoideum was located on the 5th segment, whereas alate aphids also presented placoid sensilla on the 3rd antennal segment. Immunocytochemical localization of odorant-binding proteins (OBPs) was performed on ultrathin sections of antennal chemosensilla. The antiserum against OBP7 intensively labeled all placoid sensilla from both primary and secondary rhinaria, with gold granules concentrated in the lymph surrounding the dendrite. OBP6 and OBP3 could also be detected in placoid sensilla, but less strongly than OBP7. Barely significant reaction or no reaction was observed with antibodies against OBP8.