De novoassembled transcriptome of horned gall aphid,Schlechtendalia chinensisBell, suggest changes in functional gene expression during host alternation

Abstract

The horned gall aphid, Schlechtendalia chinensis Bell, is the most economically valuable galling aphid. It accounts for approximately 75% of Chinese gallnut production, which is important for medical and chemical purposes. The horned gall aphid feeds on the Chinese sumac tree, Rhus chinensis, during the summer, induces galls, and overwinters on the moss Plagiomnium spp. However, the sequence information of S. chinensis is limited, and the functional gene expression changes during host alternation remain obscure. In this study, the transcriptome of the horned gall aphid was sequenced using high-throughput sequencing technology. Approximately 49 million reads were obtained and were assembled into 99 366 transcripts and 47 400 unigenes. Annotation was performed using a BLAST search against primary databases such as NCBI nr and Swiss-Prot, as well as enrichment analysis by GO, KOG and KEGG. Differentially expressed genes between spring and autumn migrant aphids were compared, and the expression levels of many genes related to detoxification, digestion and other functional genes were found to have changed, reflecting the adaptation ability of horned gall aphids in different seasons and hosts. Functional genes in wax biosynthesis were upregulated in spring migrant aphids. This study analyzed the expression profile difference between spring and autumn migrant aphids to approach the real functional genes change during host alternation. The transcriptome provides a basis to understanding the functional genes during gall aphid host alternation and the related physiological and molecular characteristics.