Identification of microRNA-like RNAs in Ophiocordyceps sinensis

Ophiocordyceps sinensis is well known as a traditional Chinese medicine and has widely been used for over 2,000 years to stimulate immune system, decrease blood pressure and to inhibit tumor growth. While miRNAs are increasingly recognized for their roles in post-transcriptional regulation of gene expression in animals and plants, miRNAs in fungi were less studied until the discovery of microRNA-like RNA (milRNA). High-throughput sequencing and bioinformatics approaches were used to identify conserved and novel milRNAs in O. sinensis. 40 conserved milRNAs were identified, while 23 pre-miRNA candidates encoding 31 novel milRNAs were predicted. Furthermore, the potential target genes of milRNAs in human were predicted and gene ontology analysis was applied to these genes. Enrichment analysis of GO-represented biological process showed that target genes of both conserved and novel milRNAs are involved in development, metabolic and immune processes, indicating the potential roles of milRNAs of O. sinensis in pharmacological effects as health food and traditional Chinese medicine. This study is the first report on genome-wide analysis of milRNAs in O. sinensis and it provides a useful resource to further study the potential roles of milRNAs as active components of O. sinensis in health food or traditional Chinese medicine.