RNA-Seq-based transcriptome and the reproduction-related genes for the aphid Schlechtendalia chinensis (Hemiptera, Aphididae).

Chinese galls form on sumac plants (Rhus chinensis) and are used for medicinal and chemical purposes, due to their richness in tannins. The galls are formed by aphids, the most prominent of which is Schlechtendalia chinensis, which forms horn-shaped galls on the winged rachis of R. chinensis. S. chinensis has a complex life cycle, including both R. chinensis and certain mosses as hosts, as well as the existence of both sexual and asexual reproduction (cyclical parthenogenesis). Previous studies have shown that the alternate occurrence of sexual and asexual reproduction relies on many environmental factors, such as temperature, photoperiod, and host-plant. However, the sexual and asexual modes of reproduction are poorly understood on the molecular level. We aimed to identify genes that respond to changes in temperature that may be related to the reproduction process. We compared the transcriptome of two samples of S. chinensis, which had been reared at different temperatures. Using gene ontology analysis, a total of 51 evolutionary conserved genes related to reproduction determination in insects were identified. Of these genes, S. chinensis harbors 42 genes. When we analyzed aphids that had asexually or sexually produced offspring, eight out of these 42 genes were identified and expressed differently in two temperature conditions. This is the first report on genes associated with reproduction determination in S. chinensis, which has a complex life cycle. Genes, expressed differently in response to different temperature conditions will be helpful to understand the mechanism of aphid reproductive determination.