Molecular Mechanism Of Sex Pheromone Communication In Streltzoviella Insularis

Streltzoviella insularis is an important wood-boring pest in landscape greening in China.Due to the characteristics of wide distribution,large number of hosts,high population density and strong fertility of this species,once S.insularis occurred,they often seriously damaged the ecological environment and urban appearance,causing great economic losses.At present,the female sex pheromone components of S.insularis have been successfully identified,including?Z?-3-tetradecenyl acetate?Z3-14:Ac?,?E?-3-tetradecenyl acetate?E3-14:Ac?and?Z?-5-dodecenyl acetate?Z5-12:Ac?.The male moths can be effectively trapped in the forest by using a combination of these components in a special ratio.However,the molecular mechanism of sex pheromone communication in S.insularis is still unknown.In this study,the female sex pheromone gland and the female and male antennae transcriptome of S.insularis were sequenced using Illumina Hiseq ^TM 4000 platform respectively,genes related to sex pheromone biosynthesis and olfaction were identified through bioinformatics analysis,the tissue expression profiles of key genes were detected using quantitative real-time PCR.In addition,the binding properties of pheromone binding proteins and sex pheromone components were investigated by fluorescence competitive binding assay.The main results of this study were shown as follows:?1?50 genes that might be involved in sex pheromone biosynthesis were identified by the female sex pheromone gland transcriptome of S.insularis,including one pheromone biosynthesis-activating neuropeptide receptor?PBANR?,two acetyl-Co A carboxylases?ACCs?,five fatty acid synthetases?FASs?,17 desaturases?DESs?,13 fatty acyl-Co A reductases?FARs?,five alcohol dehydrogenases?ADs?,five aldehyde reductases?ARs?and two acetyltransferases?ATFs?genes.Among of them,Sins DES8,Sins DES17,Sins FAR6 and Sins AR5 were highly expressed in the sex pheromone gland transcriptome.Meanwhile the biosynthesis pathways of three sex pheromone components in S.insularis were defined.?2?210 olfactory protein genes were identified by the female and male antennae transcriptome of S.insularis,including 28 odorant binding proteins?OBPs?,12 chemosensory proteins?CSPs?,two sensory neuron membrane proteins?SNMPs?,11 ionotropic receptors?IRs?56 odorant receptors?ORs?and 101odorant degrading enzymes?ODEs?genes.Among of them,Sins OBP4,Sins OBP15,Sins PBP1-3,Sins GOBP1-2,Sins CSP2,Sins CSP6,Sins CSP8,Sins Orco,Sins SNMP1-2,Sins CEX3,Sins CYP20 and Sins CYP36 were highly expressed in the female and male antennae transcriptome.?3?The tissue expression profiles of two ACCs and ten DESs genes in the female S.insularis were determined.Among of them,Sins ACC2,Sins DES6 and Sins DES8 were significantly expressed in the sex pheromone glands,and Sins ACC1,Sins DES1,Sins DES3,Sins DES4 and Sins DES7 were highly expressed in the antennae.?4?The tissue expression profiles of 28 OBPs,12 CSPs and two SNMPs genes in the female and male S.insularis were determined.28 genes were significantly expressed in the antennae,among of them,15genes?Sins OBP2,Sins OBP4,Sins OBP6-7,Sins OBP9-10,Sins OBP12,Sins OBP14-15,Sins OBP22-23,Sins PBP1-2,Sins GOBP2 and Sins CSP10?were expressed at significantly higher levels in males than in females,two genes?Sins OBP13 and Sins OBP20?were expressed at significantly higher levels in the female antennae than in the male antennae,11 genes?Sins OBP5,Sins OBP18,Sins PBP3,Sins GOBP1,Sins CSP2-4,Sins CSP6,Sins CSP8 and Sins SNMP1-2?were not significantly different between the female and male antennae;Sins OBP17 was more highly expressed in the male legs than in other tissues;Sins OBP8,Sins OBP16 and Sins OBP19 were significantly expressed in the male genitalia.?5?Three pheromone binding proteins of S.insularis?Sins PBP1-3?and their binding properties with sex pheromone components were investigated.Among of them,Sins PBP1-3 had strong binding ability to Z3-14:Ac with binding constant 2.49?M,6.33?M and 3.12?M,respectively;Sins PBP2 and Sins PBP3had great binding ability to E3-14:Ac with binding constant 5.54?M and 4.10?M,respectively;Sins PBP1and Sins PBP3 had high binding ability to Z5-12:Ac with binding constant 3.03?M and 1.95?M,respectively.In conclusion,this study identified a series of genes that might be involved in sex pheromone biosynthesis and olfaction,and performed tissue expression patterns of key genes.The putative biosynthetic pathways for three sex pheromone components were revealed,and the function of Sins PBP1-3 in S.insularis were validated.These results are helpful in understanding the molecular mechanism of sex pheromone communication in S.insularis,and provide theoretical guidance for the development of new pest control methods.