Data from: Differential gene expression according to race and host plant in the pea aphid

Host-race formation in phytophagous insects is thought to provide the opportunity for local adaptation and subsequent ecological speciation. Studying gene expression differences amongst host races may help to identify phenotypes under (or resulting from) divergent selection and their genetic, molecular and physiological bases. The pea aphid (Acyrthosiphon pisum) comprises host races specializing on numerous plants in the Fabaceae and provides a unique system for examining the early stages of diversification along a gradient of genetic and associated adaptive divergence. In this study, we examine transcriptome-wide gene expression both in response to environment and across pea aphid races selected to cover the range of genetic divergence reported in this species complex. We identify changes in expression in response to host plant, indicating the importance of gene expression in aphid–plant interactions. Races can be distinguished on the basis of gene expression, and higher numbers of differentially expressed genes are apparent between more divergent races; these expression differences between host races may result from genetic drift and reproductive isolation and possibly divergent selection. Expression differences related to plant adaptation include a subset of chemosensory and salivary genes. Genes showing expression changes in response to host plant do not make up a large portion of between-race expression differences, providing confirmation of previous studies’ findings that genes involved in expression differences between diverging populations or species are not necessarily those showing initial plasticity in the face of environmental change.植食性昆虫的宿主宗形成被认为可为局域适应及后续的生态物种形成提供重要契机。探究不同宿主宗间的基因表达差异，或可帮助识别处于分歧选择作用下（或由分歧选择产生）的表型，及其遗传、分子与生理基础。豌豆蚜（Acyrthosiphon pisum）拥有多个特化于豆科（Fabaceae）多种植物的宿主宗，为探究沿遗传与适应性分化梯度的早期分化进程提供了独特的研究体系。本研究选取覆盖该物种复合群已报道的各类遗传分化范围的豌豆蚜宿主宗，分析其响应环境与跨宿主宗的全转录组（transcriptome-wide）基因表达模式。研究团队鉴定出响应宿主植物的基因表达变化，证实了基因表达在蚜虫-植物互作中的关键作用。不同宿主宗可通过基因表达谱加以区分，且分化程度越高的宿主宗之间，差异表达基因（differentially expressed genes）的数量也越多；宿主宗间的此类表达差异可能源于遗传漂变与生殖隔离，或还受到分歧选择的影响。与植物适应相关的表达差异包含一类化学感受基因（chemosensory genes）与唾液腺基因（salivary genes）。响应宿主植物的表达变化基因，在宿主宗间的差异表达基因中并未占据较大比例，这验证了此前研究的结论：分化种群或物种间的表达差异基因，未必是那些在环境变化下表现出初始可塑性的基因。