基于转录组学的管纹艳虎天牛表皮蛋白基因家族的鉴定及特征分析

Identification and characterization of cuticular protein gene families of Rhaphuma horsfieldi based on transcriptomics

表皮蛋白(cuticular protein,CP)在昆虫生长发育、抵御外界不良环境等方面具有重要作用,但在管纹艳虎天牛Rhaphuma horsfieldi中关于CP基因的研究尚属空白。本研究基于已测序的转录组,通过生物信息学技术从管纹艳虎天牛中一共鉴定到108个CP基因,包括41个CP-RR1、30个CP-RR2、8个CPAP1、7个CPAP3、3个CPCFC、14个CPU和5个TWDL基因,其中39个基因具有全长序列。结构域及保守基序分析表明,管纹艳虎天牛的CP-RR1和CP-RR2家族均具有1个保守的Chitin_bind_4结构域,其中CP-RR1家族完全符合昆虫经典的R&R基序(G-X(8)-G-X(6)-Y),而CP-RR2家族的保守基序(G-X-Y-X(5)-D-G-X(6)-Y)出现了变化。进化分析表明,管纹艳虎天牛RhorCPs可划分为7个家族:CP-RR1、CP-RR2、CPAP1、CPAP3、CPCFC、CPU和TWDL。表达谱结果表明,RhorCPs基因的表达谱具有多样性,部分基因在检测的组织中表达量均较低;部分基因在触角和跗节中特异或高表达,可能具有化学感受功能;部分基因在不含触角和跗节的身体中有表达,可能与成虫表皮的发育和形成有关。研究结果不仅可为后续管纹艳虎天牛RhorCPs基因的功能研究奠定基础,还可筛选到害虫防治的潜在分子靶标。

Cuticular proteins(CPs)in insects are of particular importance for the development and against adverse environmental conditions.However,no information for CP genes of Rhaphuma horsfieldi is available to date.Based on the transcriptome of R.horsfieldi,here totally 108 CP genes were identified using a bioinformatics approach including 41 CPs with a Rebers and Riddiford motifs(CP-RR1),30 CP-RR2,8 CPs analogous to peritrophins(CPAP1),7 CPAP3,3 CPs with two to three copies of a C-x(5)-C motifs(CPCFC),14 CP unclassified(CPU)and 5 tweedles(TWDL)genes.Of these,39 CP genes had full-length open reading frames.Structural domain and conserved motif analyses showed that both RhorCP-RR1 and RhorCP-RR2 families had a conserved Chitin_bind_4 domain,in which the CP-RR1 family completely matched insect classical R&R motif(G-X(8)-G-X(6)-Y),while that of the CP-RR2 family was changed into G-X-Y-X(5)-D-G-X(6)-Y.Phylogenetic analysis showed that RhorCPs were classified into 7 families:CP-RR1,CP-RR2,CPAP1,CPAP3,CPCFC,CPU and TWDL.Expression profiling analysis revealed that RhorCP genes were broadly expressed in various tissues.Some of RhorCPs were detected in all tested tissues at low levels.Parts of RhorCPs were highly expressed in antennae and tarsi,suggesting their chemosensory roles.Some were detected in the bodies without the antennae and tarsi,possibly associated with the formation and development of adult cuticle.Together,this study provides reference data for subsequent functional studies of R.horsfieldi CP genes,and meanwhile identifies candidate molecular targets for pest control of this beetle.