De novo transcriptome sequencing of Paecilomyces tenuipes revealed genes involved in adenosine biosynthesis

The use of Paecilomyces tenuipes (P. tenuipes), a Chinese medicinal fungus in scientific research, is limited due to its low adenosine content. To improve adenosine production, the present study investigated the gene network of adenosine biosynthesis in P. tenuipes via transcriptome analysis. Mycelia of P. tenuipes cultured for 24 h (PT24), 102 h (PT102) and 196 h (PT192) were subjected to RNA sequencing. In total, 13,353 unigenes were obtained. Based on sequence similarity, 8,099 unigenes were annotated with known proteins. Of these 8,099 unigenes, 5,123 had functions assigned based on Gene Ontology terms while 4,158 were annotated based on the Eukaryotic Orthologous Groups database. Moreover, 1,272 unigenes were mapped to 281 Kyoto Encyclopedia of Genes and Genomes pathways. In addition, the differential gene expression of the three libraries was also performed. A total of 601, 1,658 and 628 differentially expressed genes (DEGs) were detected in PT24 vs. PT102, PT24 vs. PT192 and PT102 vs. PT192 groups, respectively. Reverse transcription-quantitative PCR was performed to analyze the expression levels of 14 DEGs putatively associated with adenosine biosynthesis in P. tenuipes. The results showed that two DEGs were closely associated with adenosine accumulation of P. tenuipes. The present study not only provides an improved understanding of the genetic information of P. tenuipes but also the findings can be used to aid research into P. tenuipes.