Abstract: 【Aim】 To screen the responsive genes of the silkworm (Bombyx mori) against infection by Beauveria bassiana in order to further elaborate its molecular mechanisms of defensing B. bassiana infection. 【Methods】 High throughput Solexa sequencing technology was employed in the transcriptome analysis of silkworm larvae of the infected and uninfected (control) groups. Differentially expressed genes (DEGs) and their functions, classifications and pathways were analyzed by bioinformatics methods. Ten DEGs were further identified by fluorescence quantitative PCR. 【Results】 With Solexa sequencing and bioinformatic analysis, 377 DEGs including 236 up-regulated genes and 141 down-regulated genes were identified. KEGG pathway analysis indicated that there were both up- and down-regulated DEGs in any pathway. Twelve up-regulated DEGs and 26 down-regulated ones were involved in three significantly enriched KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, i. e., ribosome, aminoacyl-tRNA biosynthesis and spliceosome pathways. Both the quantitative PCR and Solexa sequencing results indicated that the immune response-related genes including lysozyme, heat shock protein, glutathione S-transferase and peptidoglycan recognition protein genes were all up-regulated. 【Conclusion】 The differentially expressed genes identified in this study, especially those up-regulated ones, are possibly involved in the silkworm response against B. bassiana invasion. The genes related to immune response such as those encoding lysozyme, heat shock protein, glutathione S-transferase and peptidoglycan recognition protein may be directly involved in immune recognition and defense of the silkworm against the B. bassiana infection. The results provide a new basis and clues for clarifying the mechanisms of interaction between the silkworm and entomopathogenic fungi at the molecular level.

Key words:  Bombyx mori, Beauveria bassiana, immune response, transcriptome, differentially expressed gene