Analysis Of Tissue Specific Expression And Binding Characteristics Of General Odorant Binding Proteins (GOBPs) From The Meadow Moth

The meadow moth, Loxostege sticticalis L., is an important agricultural and husbandry pest in the north of China, which always break out periodically. It is a polyphagous insect, mainly and seriously feeding on soybean, beet, clover and sunflower etc. Because of its enormous damage, related researches have been paid more and more attention. The expression patterns were analysised by QPCR and the binding characteristics of the odorant-binding proteins using fluorescence binding assay. The main results as follows:1, Tissue specific expression of Lsti-GOBP has been tested using QPCR. Results showed:Lsti-GOBPs specifically expressed in antennae, and also Lsti-GOBP 1 expressed more in female than male and Lsti-GOBP2 vice versa. Both the expressions reach the maximum in 3rd instars with two peaks in their expression curves.2, Based on the known Lsti-GOBPs gene sequences, we successfully constructed the prokaryotic expression system and obtained the purified Lsti-GOBPs proteins by affinity chromatography.3, There is a reaction between Lsti-GOBPs and probe N-phenyl-1-naphthylamine (1-NPN). With the increase of the 1-NPN, the endogenous fluorescence of Lsti-GOBPs was down-regulated and the exogenous florescence up-regulated simultaneously. The binding constants of Lsti-GOBP1 and Lsti-GOBP2 are 2.842 and 1.436.4, The binding characteristics of Lsti-GOBPs to 50 kinds of chemical molecules were further studied using 1-NPN as fluorescent probes. The results showed that Lsti-GOBP1 had the capability of binding to only 1-hexanol,1-heptanol, cinnamaldehyde and camphene, which replaced 1-NPN from Lsti-GOBP1 by 50%, and the binding constants were 8.997,7.283,7.289 and 9.814μmol/L, respectively.5, The results also showed that Lsti-GOBP2 had the capability of binding to 1-hexanol, Cis-3-hexen-l-ol, Cis-3-exenal,1-Heptanol, Valeraldehyde, a-ionone,β-ionone, Benzaldehyde, Cinnamaldehyde, Phenyl acetaldehyde, 2,4-Di-tert-butylphenol and Camphor, which replaced 1-NPN from Lsti-GOBP1 by 50%, and the binding constants were 3.576,5.409,3.606,3.293,4.837,2.418 3.576,6.161,6.211.6.085,5.959,4.795μmol/L, respectively.