Evidence of the Involvement of a Plus-C Odorant-Binding Protein HparOBP14 in Host Plant Selection and Oviposition of the Scarab Beetle .

is one of the agriculturally important scarab beetle pests in China. In this study, was cloned, which is the most abundantly expressed among the OBP genes in the legs of female adults. Sequence comparison and phylogenetic analysis showed that HparOBP14 has a Plus-C structure motif. The expression profile analysis revealed that expression was the highest in the female antennae and then in the legs. The fluorescence competitive binding experiment of the recombinant HparOBP14 protein showed that HparOBP14 had an affinity with 6-methyl-5-heptene-2-one (plant volatile), 3-methylindole, -cymene, methanol, formaldehyde, α-pinene, and geraniol (organic fertilizer volatile). Knockdown expression decreased significantly the EAG response of the injected female adults to -cymene, methanol, formaldehyde, α-pinene, and geraniol. Similarly, the injected female adults were significantly less attracted to geraniol and methanol. Therefore, HparOBP14 might bind organic matter volatiles during oviposition. These results are not only helpful to analyze the olfactory recognition mechanism of female adult when choosing suitable oviposition sites, but also to provide target genes for green prevention and control of in the future.