Yu-Yue Lu,Shu-Lin Li,Fu-Peng Li,Zi-Hao Long,Ting-Ting Lu,Nai-Yong Liu
Three Tomicus bark beetles ( T. yunnanensis , T. brevipilosus and T. minor ) coexist in the trunks of Pinus yunnanensis but possess relatively independent spatio-temporal ecological niches. This makes them become a good case for addressing functional differentiation of chemosensory-related proteins among closely related species in odorant recognition and insecticide sequestering. In this study, we used odorant binding protein (OBP) orthologues highly expressed in antennae to illustrate this question. We first identified 33, 35 and 34 OBPs from T. yunnanensis , T. brevipilosus and T. minor , respectively, with 33 groups of OBP orthologues. Sequence and phylogenetic analyses revealed the conservation and differences of OBP orthologues across three Tomicus beetles. Expression profiles revealed that the majority of Tomicus OBPs were abundantly expressed in antennae where 11 groups of OBP orthologues shared a significantly antenna-enriched distribution. Four groups of antennal OBP orthologues (OBP2, OBP9, OBP10 and OBP16 totaling 12 genes) presented diverse ligand-binding properties, responding differently to five classes of ecologically relevant odorants as well as various insecticides. In particular, OBP orthologues were tuned differentially to host and non-host odorants, and chlorpyrifos was identified as the best ligand for 12 Tomicus OBPs. Our study thus sheds light on functional conservation and divergence of OBP orthologues among three sympatric Tomicus bark beetles, possibly as an implication for the early or late of host colonization, ecological niche differences and the strong habitat adaptation.
Aims This study aimed to design the Chinese Modified Olfactory Identification (CMOI) test based on the Sniffin' Sticks Olfactory Identification (SSOI) test by changing unfamiliar distractors and odors for more familiar ones for the Chinese population. Materials and methods We recruited 200 healthy volunteers (103 males and 97 females, aged 18–65 years, mean age 35.04 years, SD 10.96); in a survey, 100 volunteers rated their familiarity with 121 odors, including all the SSOI test odor descriptors and common odors in Chinese daily life. The SSOI test was modified according to the survey results. The other 100 volunteers were tested three times using the SSOI test, the Modified Distractors Olfactory Identification (MDOI) test established by modifying distractors in the SSOI test, and the CMOI test developed by using familiar unpleasant odors to displace the odors with low correct recognition rates in the MDOI test. We compared the test scores of the volunteers during the modification process. Results Volunteers were unfamiliar with 31 odor descriptors in the SSOI test; 23 distractors with low familiarity were displaced with more familiar distractors. The three odors with the lowest correct recognition rate in the MDOI test (apple, leather, and pineapple) were displaced with familiar unpleasant odors. The test scores were significantly higher in the CMOI test than in others ( p < 0.0001); the correct recognition rate in the CMOI test was significantly higher than in the SSOI test ( p < 0.01). Conclusion The test scores in the CMOI test were significantly improved; it prevented choosing wrongly due to unfamiliarity with an odor and its distractors.
Zhengyi Mao,Wen Zhao,Dongping Chen,Zhiyan Jiang,Qiang Liu,Jiayun Li,Yunxuan Wu,Nannan Lv,Jianting Fan
The pine-forest guardian Dastarcus helophoroides mainly rely on olfaction to locate its host accurately and interact socially. Odorant binding proteins of D. helophoroides play an important role in olfactory recognition and transporting odors to olfactory receptors to trigger signal transduction. However, some compounds affect olfactory recognition of D. helophoroides by binding to odorant binding proteins. In this study, DhelOBP4 and DhelOBP21, which are involved in the recognition of plant volatiles, were expressed to explore compounds that affect olfactory recognition. The affinity of 24 compounds with DhelOBP4 and DhelOBP21 was investigated by vitro fluorescence competitive binding assays. It was found that cyetpyrafen, chlorfenapyr and spirodiclofen had high affinity with DhelOBP4 and DhelOBP21. At the same time, we found that these three pesticides had a good evasive effect on the D. helophoroides and elicited EAG response in a dose-dependent manner. Besides, it was found that silencing DhelOBP4 and DhelOBP21 would affect D. helophoroides identifying these three pesticides. Through homology modeling and molecular docking, we identified key amino acid sites involved in the binding of DhelOBP4 and DhelOBP21 to these three pesticides, which might revealed their specific binding molecular interactions. This study is helpful to provide a valuable addition of OBP-pesticide interactions of D. helophoroides .
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