Abstract: Culture medium composition significantly affects carotenoid biosynthesis in Cordyceps militaris. In this study, high-throughput sequencing technology was used to investigate the transcriptomic differences of C. militaris mycelia (CM10_RL and CM10_WL) cultured with different media. The genes related to the biosynthesis of carotenoids in C. militaris were identified by bioinformatics analysis. The results showed that the carotenoid content of CM10_WL was significantly higher than that of CM10_RL. A total of 318 up-regulated genes and 618 down-regulated genes were found in CM10_WL compared with CM10_RL. Gene Ontology (GO) analysis indicated that the differentially expressed genes (DEGs) were mainly classified into the “metabolic process”, “membrane” or “catalytic activity” terms. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis suggested that these DEGs were mainly enriched in “metabolic pathways”. Therefore, all the transcripts derived from RNA-seq data were searched against the carotenoid biosynthetic pathway in the KEGG database, and the results showed that the CCM_06728 and CCM_09155 genes were involved in the biosynthesis of carotenoids. This study lay a foundation for further elucidating the biosynthetic pathway of carotenoids in C. militaris.

Key words: Cordyceps militaris; high-throughput sequencing; transcriptome; pigment; carotenoid; differentially expressed gene