灭字脊虎天牛触角转录组中气味结合蛋白基因的鉴定及表达谱分析

Identification and Expression Profile Analysis of Odorant Binding Protein Genes from Xylotrechus quadripes Chevrolat (Coleoptera:Cerambycidae)

【目的】发掘灭字脊虎天牛(Xylotrechus quadripes Chevrolat)成虫触角中的OBP基因,明确OBP基因在成虫不同组织的表达情况。【方法】采用Illumina HiSeq^(TM) 2000测序平台对灭字脊虎天牛的触角进行转录组测序,利用BLAST同源搜索的方法鉴定OBP基因,采用RT-PCR技术研究OBP基因的表达谱。【结果】从灭字脊虎天牛的触角转录组中共鉴定到24个OBP基因,所有OBP基因均具有全长开放阅读框(123~180个氨基酸)和信号肽序列(16~23个氨基酸)。多序列比对结果表明,不同OBP间一致性较低,其平均值为19.4%。序列比对和进化树分析结果表明,9个OBP具有6个保守的半胱氨酸,属于Classic OBPs家族;15个OBP具有4个保守的半胱氨酸,属于Minus-C OBPs家族。RT-PCR结果表明,Xqua OBP4、OBP8、OBP18和OBP21在触角特异表达;Xqua OBP2、OBP3、OBP7和OBP20在触角高表达,另外在其他组织中也有表达;其他OBPs基因在检测的两个或多个组织中均有不同程度的表达。【结论】从灭字脊虎天牛触角转录组中共鉴定得到24个OBP基因,其中部分基因在触角特异或高表达,很可能参与嗅觉功能;部分基因在非嗅觉组织中有表达,很可能具有非嗅觉功能。

【Objective】The objective of the study was to identity odorant binding protein （OBP） genes inadult antennae of Xylotrechus quadripes Chevrolat and to explore their expression patterns in differenttissues.【Method】The transcriptome of X. quadripes was sequenced using Illumina HiSeqTM 2000. Further,a homology-based method was employed to identify OBP genes from the transcriptome. The expressionpatterns of OBPs were determined by reverse transcription PCR （RT-PCR）.【Result】24 transcriptsencoding putative OBPs were identified from X. quadripes antennal transcriptome, all of which sharedfull-length open reading frames （120-180 amino acids） and signal peptides at N-terminal （16-23 aminoacids）. Multiple sequence alignment results showed that a low identity was observed among differentOBPs, with an average protein identity of 19.4%. Analyses of sequence alignment and phylogenetic treeshowed that 9 OBPs had six conserved cysteine （Cys） residues, and belonged to Classic OBPs family; 15OBPs had four conserved Cys residues and belonged to Minus-C OBPs family. The results of RT-PCRshowed that XquaOBP4, OBP8, OBP18 and OBP21 were specifically expressed in antennae; XquaOBP2,OBP3, OBP7 and OBP20 were highly expressed in the antennae, and slightly in other tissues; otherOBPs were expressed in at least two tissue types.【Conclusion】Based on the antennal transcriptome of X.quadripes, 24 OBP genes were identified. Expression pattern analysis revealed that some OBP genes werespecifically or highly expressed in antennae, possibly having olfactory functions; whereas some were exp-ressed in non-olfactory tissues, possibly guiding non-olfactory behaviors.