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 among 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 specialising 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 sub-set 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（host-race）形成被认为为局部适应及后续的生态物种形成提供了潜在契机。探究宿主宗间的基因表达差异，有助于识别处于歧化选择作用下或由歧化选择产生的表型，及其遗传、分子与生理基础。豌豆蚜（Acyrthosiphon pisum）包含多个特化于豆科（Fabaceae）多种植物的宿主宗，为探究沿遗传与关联适应分化梯度的早期物种分化进程提供了独特的研究体系。本研究针对该物种复合群已报道的遗传分化谱系，选取不同豌豆蚜宿主宗，对全转录组（transcriptome）水平的基因表达开展双维度分析：既探究环境响应介导的表达变化，也分析跨宿主宗的表达差异。本研究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-植物互作中的核心作用。不同宿主宗可通过基因表达特征加以区分，且宿主宗间的分化程度越高，差异表达基因的数量也越多；宿主宗间的这些表达差异可能源于遗传漂变、生殖隔离，亦或歧化选择作用。与植物适应相关的表达差异涵盖了化学感知与唾液基因的一个子集。响应宿主植物的表达变化基因并未在宿主宗间的表达差异中占据较大比例，这验证了既往研究的结论：分化种群或物种间的表达差异相关基因，未必是面对环境变化时表现出初始可塑性的基因。