Huang Xin, Poelchau Monica F, Armbruster Peter A
Department of Biology, Georgetown University, Washington, D.C., United States of America.
PLoS Negl Trop Dis. 2015 Apr 21;9(4):e0003724. doi: 10.1371/journal.pntd.0003724. eCollection 2015 Apr.
Aedes albopictus is a vector of increasing public health concern due to its rapid global range expansion and ability to transmit Dengue virus, Chikungunya virus and a wide range of additional arboviruses. Traditional vector control strategies have been largely ineffective against Ae. albopictus and novel approaches are urgently needed. Photoperiodic diapause is a crucial ecological adaptation in a wide range of temperate insects. Therefore, targeting the molecular regulation of photoperiodic diapause or diapause-associated physiological processes could provide the basis of novel approaches to vector control.
METHODOLOGY/PRINCIPAL FINDINGS: We investigated the global transcriptional profiles of diapause induction in Ae. albopictus by performing paired-end RNA-Seq of biologically replicated libraries. We sequenced RNA from whole bodies of adult females reared under diapause-inducing and non-diapause-inducing photoperiods either with or without a blood meal. We constructed a comprehensive transcriptome assembly that incorporated previous assemblies and represents over 14,000 annotated dipteran gene models. Mapping of sequence reads to the transcriptome identified differential expression of 2,251 genes in response to diapause-inducing short-day photoperiods. In non-blood-fed females, potential regulatory elements of diapause induction were transcriptionally up-regulated, including two of the canonical circadian clock genes, timeless and cryptochrome 1. In blood-fed females, genes in metabolic pathways related to energy production and offspring provisioning were differentially expressed under diapause-inducing conditions, including the oxidative phosphorylation pathway and lipid metabolism genes.
CONCLUSIONS/SIGNIFICANCE: This study is the first to utilize powerful RNA-Seq technologies to elucidate the transcriptional basis of diapause induction in any insect. We identified candidate genes and pathways regulating diapause induction, including a conserved set of genes that are differentially expressed as part of the diapause program in a diverse group of insects. These genes provide candidates whose diapause-associated function can be further interrogated using functional genomics approaches in Ae. albopictus and other insects.
白纹伊蚊因其在全球范围内的迅速扩张以及传播登革热病毒、基孔肯雅病毒和多种其他虫媒病毒的能力，成为日益引起公共卫生关注的病媒。传统的病媒控制策略对白纹伊蚊大多无效，迫切需要新的方法。光周期滞育是多种温带昆虫的关键生态适应。因此，针对光周期滞育或滞育相关生理过程的分子调控，可为病媒控制新方法提供基础。
方法/主要发现：我们通过对生物学重复文库进行双末端RNA测序，研究了白纹伊蚊滞育诱导的全基因组转录谱。我们对在诱导滞育和非诱导滞育光周期下饲养的成年雌性白纹伊蚊的全身RNA进行了测序，这些蚊子有的有血餐，有的没有血餐。我们构建了一个综合转录组组装体，该组装体整合了先前的组装体，并代表了超过14,000个注释的双翅目基因模型。将序列读数映射到转录组，确定了2,251个基因因诱导滞育的短日照光周期而差异表达。在未吸血的雌性蚊子中，滞育诱导的潜在调控元件在转录水平上上调，包括两个典型的生物钟基因，即无时间蛋白和隐花色素1。在吸血的雌性蚊子中，与能量产生和后代供应相关的代谢途径中的基因在诱导滞育条件下差异表达，包括氧化磷酸化途径和脂质代谢基因。
结论/意义：本研究首次利用强大的RNA测序技术阐明了任何昆虫滞育诱导的转录基础。我们鉴定了调控滞育诱导的候选基因和途径，包括一组保守基因，这些基因在不同昆虫群体中作为滞育程序的一部分差异表达。这些基因提供了候选对象，其与滞育相关的功能可在白纹伊蚊和其他昆虫中使用功能基因组学方法进一步探究。
