INTERGENERIC DISTRIBUTION AND IMMUNOLOCALIZATION OF A PUTATIVE ODORANT-BINDING PROTEIN IN TRUE BUGS (HEMIPTERA, HETEROPTERA)

Lygus antennal protein (LAP) is an olfactory-related protein of the ta rnished plant bug Lygus lineolaris (Hemiptera, Heteroptera: Miridae), a hemimetabolous insect, In previous work, a polyclonal antiserum was generated against the N-terminal sequence of LAP; LAP immunoreactivity was strongest in antennae of adult males, but was also present in ant ennae of adult females and of nymphs, In the current study, LAP immuno reactivity was examined to determine the species specificity and the t issue and cellular localization of LAP expression, Western blot analys is indicated that LAP immunoreactivity was present in the antennae of the male congeners L, lineolaris and L, hesperous, but was not detecta ble in male antennae of the more distant relatives Podisus maculiventr is or Nezara viridula (Hemiptera, Heteroptera: Pentatomidae), Western blot analysis further confirmed that LAP expression was restricted to antennal tissue, Histological analyses showed that LAP expression with in the antennae was specifically associated with chemosensory sensilla on the antenna, Within the sensilla, LAP immunoreactivity was distrib uted throughout the extracellular lumen and was concentrated in dense granules within the cytoplasm of sensillar support cells. LAP immunore activity was restricted to a subset of antennal chemosensory sensilla, specifically the multiporous olfactory sensilla, These findings sugge st that LAP has an important olfactory function in Lygus sp., possibly related to that of odorant-binding proteins (OBP) found in other inse ct orders, If so, LAP would be the first OBP-like protein characterize d outside the Endopterygota.