Cloning and expression analysis of seven odour binding protein genes from Leptocybe invasa

In order to understand the olfactory perception mechanism of Leptocybe invasa, seven odour binding protein genes, named LinvOBP2, LinvOBP5, LinvOBP7, LinvOBP9, LinvOBP11, LinvOBP18, LinvOBP23 were successfully cloned from L. invasa. The bioinformatics software was used to analyze the physical and chemical characteristics and structural characteristics of the proteins encoded by the seven genes, and the phylogenetic relationships of OBPs and other insect OBPs were analyzed. Real-time quantitative PCR was used to analyze the expression of OBPs gene under different volatiles treatment. The results showed that the 7 LinvOBPs genes were about 400 bp in length and contained 6 conserved L-Cysteine. The N-terminal of the 7 LinvOBPs contained signal peptide cleavage sites and a large number of α-helices in secondary structure prediction, it was beneficial to the formation of hydrophobic binding cavity, and can promote its binding with odor molecules. The LinvOBPs of L. invasa and the CcOBPs of Chouioia cunea were clustered in the same branch and had high affinity. There were significant differences in the response of different LinvOBPs to different volatiles. The regulation of certain volatiles on LinvOBPs expression, especially for para-cymene, eucalyptol and d-terpenediene, could up-regulate the expression of multiple LinvOBPs. All the seven LinvOBPs genes play an important role in the recognition of host eucalyptus. Among them, the recognition of para-cymene, eucalyptol and d-terpendiene by LinvOBPs is helpful to reveal the molecular mechanism of the specific recognition of host eucalyptus by L. invasa.