To investigate the expression profile of highly expressed genes (HEGs) and its potential role during Apis cerana cerana infected by Nosema ceranae, RNA-seq was used to sequence the midguts of A. c. cerana workers at 7 d and 10 d post infection by N. ceranae, followed by continuously mapping the genomes of Apis cerana and N. ceranae to filter out the data of A.c.cerana. In total, 180 237 114 and 36 054 033 clean reads were obtained from N. ceranae infecting A. c. cerana worker (Nc1 and Nc2), respectively. According to the criterion that the FPKM value >15, 1 482 and 901 HEGs in Nc1 and Nc2 were filtered out, respectively. Venn analysis showed that the total number of HEGs of the two groups was 890, and the number of specific HEGs was 592 and 11, respectively. Besides, GO classification and KEGG pathway enrichment analysis indicated the shared HEGs were distributed in 24 GO terms and enriched in 72 pathways. Further analysis demonstrated two HEGs were enriched in MAPK signaling pathway, which is closely associated with the stress response and virulence. Besides, some genes coding virulence factors such as spore wall protein, and several genes coding energy metabolism associated proteins, such as ATP/ADP translocase were highly expressed during N. ceranae infection of A. c. cerana worker. Finally, eight randomly selected HEGs were confirmed using RT-PCR. Together, these results reveal the expression profile and potential role of HEGs during N. ceranae infection of A. c. cerana worker.
