<i>De Novo</i> Transcriptome Analysis of Wing Development-Related Signaling Pathways in <i>Locusta migratoria</i> Manilensis and <i>Ostrinia furnacalis</i> (Guenée)

Background Orthopteran migratory locust, Locusta migratoria, and lepidopteran Asian corn borer, Ostrinia furnacalis, are two types of insects undergoing incomplete and complete metamorphosis, respectively. Identification of candidate genes regulating wing development in these two insects would provide insights into the further study about the molecular mechanisms controlling metamorphosis development. We have sequenced the transcriptome of O. furnacalis larvae previously. Here we sequenced and characterized the transcriptome of L. migratoria wing discs with special emphasis on wing development-related signaling pathways. Methodology/Principal Findings Illumina Hiseq2000 was used to sequence 8.38 Gb of the transcriptome from dissected nymphal wing discs. De novo assembly generated 91,907 unigenes with mean length of 610 nt. All unigenes were searched against five databases including Nt, Nr, Swiss-Prot, COG, and KEGG for annotations using blastn or blastx algorithm with an cut-off E-value of 10−5. A total of 23,359 (25.4%) unigenes have homologs within at least one database. Based on sequence similarity to homologs known to regulate Drosophila melanogaster wing development, we identified 50 and 46 potential wing development-related unigenes from L. migratoria and O. furnacalis transcriptome, respectively. The identified unigenes encode putative orthologs for nearly all components of the Hedgehog (Hh), Decapentaplegic (Dpp), Notch (N), and Wingless (Wg) signaling pathways, which are essential for growth and pattern formation during wing development. We investigated the expression profiles of the component genes involved in these signaling pathways in forewings and hind wings of L. migratoria and O. furnacalis. The results revealed the tested genes had different expression patterns in two insects. Conclusions/Significance This study provides the comprehensive sequence resource of the wing development-related signaling pathways of L. migratoria. The obtained data gives an insight into better understanding the molecular mechanisms involved in the wing development in L. migratoria and O. furnacalis, two insect species with different metamorphosis types.背景 直翅目昆虫东亚飞蝗（Locusta migratoria）与鳞翅目昆虫亚洲玉米螟（Ostrinia furnacalis）分别属于不完全变态发育与完全变态发育的昆虫类群。鉴定调控这两种昆虫翅发育的候选基因，可为深入解析变态发育的分子机制提供重要研究线索。本课题组此前已完成亚洲玉米螟幼虫的转录组（transcriptome）测序。本研究对东亚飞蝗若虫翅盘的转录组（transcriptome）进行测序与特征分析，重点聚焦于翅发育相关的信号通路。 方法与主要研究结果 采用Illumina Hiseq2000测序平台，对解剖获取的若虫翅盘进行转录组测序，获得8.38 Gb的测序数据。通过从头组装（de novo assembly）得到91907条单基因簇（unigene），平均长度为610 nt。利用blastn或blastx算法，以10^-5为E值（E-value）阈值，将所有单基因簇比对至Nt、Nr、Swiss-Prot、COG及KEGG共5个数据库进行功能注释。最终共有23359条（占比25.4%）单基因簇在至少一个数据库中获得同源序列。基于与已知调控黑腹果蝇（Drosophila melanogaster）翅发育的同源基因的序列相似性，我们分别从东亚飞蝗和亚洲玉米螟的转录组中鉴定出50条和46条潜在的翅发育相关单基因簇。上述鉴定得到的单基因簇可编码Hedgehog（Hh）、Decapentaplegic（Dpp）、Notch（N）以及Wingless（Wg）信号通路中几乎所有组分的推定直向同源蛋白，这些通路在翅发育的生长与模式形成过程中发挥关键调控作用。我们进一步检测了东亚飞蝗前后翅以及亚洲玉米螟前后翅中上述信号通路组分基因的表达谱，结果显示受试基因在两种昆虫中呈现出不同的表达模式。 结论与意义 本研究提供了东亚飞蝗翅发育相关信号通路的全面序列资源。所得数据可为深入理解两种具有不同变态发育类型的昆虫——东亚飞蝗与亚洲玉米螟的翅发育分子机制提供重要参考。