|Murphy, Charles - Charlie|
Submitted to: Annals of the New York Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/1997
Publication Date: N/A
Interpretive Summary: The tarnished plant bug, Lygus lineolaris, is a pest of a number of economically important crops. To develop effective yet environmentally sound control measures we have researched basic mechanisms of chemical reception in the plant bug. Behavioral cues, such as sex pheromones and food/oviposition site odors, are not identified for this pest. We have now identified an antennal specific protein (LAP) most likely involved in chemical reception in the plant bug. LAP cellular localization and species specificity were characterized using an antibody which we previously developed for specific tagging of LAP. LAP was found only in antennae of Lygus species and was not detectable in other bugs. On the antennae, LAP was associated with specific sensilla, the chemical sensors of the insect. A nucleic acid probe corresponding to LAP was isolated and showed that LAP is synthesized beneath the antennal cuticle in a region near the sensilla but distinct from the lymph of the sensilla. Our results suggest that LAP is an odorant-binding protein. Entomologists, neurobiologists and molecular biologists will use our results to determine chemical signals used by the plant bug and to develop biorational pest control strategies.
Technical Abstract: Odorant-binding proteins (OBPs) in insects occur within olfactory sensilla and are thought to transport chemical stimuli to receptors on dendrites of sensory neurons. Until recently, knowledge of OBPs in insects was limited to moths and Drosophila. We discovered an antennal-specific protein (LAP) with a unique N-terminal sequence in the true bug, Lygus lineolaris. We localized LAP to antennae, determined its molecular weight (15 kDa), and showed that while it was expressed in nymphal antennae, its levels dramatically increased in adults concurrent with increases in numbers of olfactory sensilla and electrical responses to odors. We used immunological techniques to show that LAP occurs only in antennae. LAP was expressed more in male antennae than in antennae of females for two Lygus species. Immunocytological studies showed LAP within the sensillar lymph of types 4, 5, and 6, all olfactory sensilla. In situ hybridization localized the transcript for LAP beneath the antennal cuticle near sensilla but distinct from LAP. These observations strongly suggest LAP to be an OBP, and our discovery and characterization of OBPs in true bugs provides a third order for use in the study of evolution of OBPs in insects.