Small RNA sequencing revealed microRNAs involved in growth and development of the oyster mushroom Pleurotus ostreatus.

Although microRNAs are essential regulators of development in complex eukaryotes, little is known about their functions in fungi. With its clear genetic system and ease of cultivation, Pleurotus ostreatus presents a model mushroom for this research. Nevertheless, the role of milRNAs in the growth and development of P. ostreatus is not yet critically understood. This study characterized milRNAs in three developmental stages of the P. ostreatus by combining small RNA sequencing, genomic alignment, and FungiSNC database. The differentially expressed milRNAs showed a dynamic expression pattern, suggesting that they may be involved in developmental regulation. The interaction diagram of milRNA-mRNA showed that there might be a synergistic relationship between milRNAs, and they may target the genes of same family related to growth and development. Four representative milRNAs were selected for qRT-PCR verification, and their expression trends were consistent with the sequencing results. In addition, the dual luciferase reporter assay showed that Po-milR-1 had targeting relationships with the hydrophobin and 3-ketoacyl-CoA thiolase. It is speculated that Po-milR-1 may participate in the growth and development of P. ostreatus by targeting these genes. This study provides new insights into the regulatory mechanism of milRNAs in P. ostreatus, and lays the foundation for further research on the molecular function of milRNAs in edible fungi.