Identification and binding characterization of three odorant binding proteins and one chemosensory protein from Apolygus lucorum (Meyer-Dur).
For the sucking insect, Apolygus lucorum, taste is essential for finding host plants and oviposition sites. In A. lucorum, taste relies largely on the sensory system located within its proboscis. In this study, we constructed a cDNA library from A. lucorum proboscises and conducted preliminary analysis of 1554 ESTs. From this collection, we identified three putative odorant-binding proteins (AlucOBP3, AlucOBP4, AlucOBP6) and one chemosensory protein (AlucCSP1). Quantitative real-time polymerase chain reaction (qPCR) was used to study the expression pattern of these four genes. All four were expressed mainly in antennae, proboscises and legs, suggestive of roles in olfaction and gustation. We expressed and purified recombinant versions of AlucOBP3, AlucOBP4, AlucOBP6, and AlucCSP1 in a prokaryotic expression system. The ligand-binding specificities of the four proteins then were investigated in competition assays using 4,4'-dianilino-1,1'-binaphthyl-5, 5'-sulfonic acid (bis-ANS) as a probe. Of the 58 small organic compounds and five cotton secondary metabolites tested, plant volatiles cannot effectively displace bis-ANS from any of the four proteins. In contrast, most of the cotton secondary metabolites have high affinities for the three OBPs and AlucCSP1, indicating that these binding proteins more likely play a role in gustation than in olfaction.
State Key Laboratory of Cotton Biology, Cotton Research Institute Chinese Academy of Agricultural Sciences, Anyang, Henan 455000, China.
Jin-Feng
JF
Hua
Shuai
S
Zhang
Jin-Jie
JJ
Cui
Dao-Jie
DJ
Wang
Chun-Yi
CY
Wang
Jun-Yu
JY
Luo
Li-Min
LM
Lv
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D005260:Female; D005786:Gene Expression Regulation; D015723:Gene Library; D006430:Hemiptera / Q000235:genetics* / Q000378:metabolism*; D019476:Insect Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011485:Protein Binding; D018035:Receptors, Odorant / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D055549:Volatile Organic Compounds / Q000378:metabolism
D019476:Insect Proteins; D018035:Receptors, Odorant; D055549:Volatile Organic Compounds; C045648:odorant-binding protein