RNA-seq, bioinformatic identification of potential MicroRNA-Like Small RNAs in the edible mushroom Agaricus bisporus and experimental approach for their validation

Although genomes from many edible mushrooms are sequenced, studies on fungal miRNAs are scarce. Most of the bioinformatic tools are designed for plants or animals but fungal miRNAs processing and expression share similarities and differences with both kingdoms. Moreover, since mushroom species such as Agaricus bisporus (white button mushroom) are frequently consumed as food, controversial discussions are still evaluating whether their miRNAs might or might not be assimilated, perhaps within extracellular vesicles (i.e exosomes). Therefore, the A. bisporus RNA-seq was studied in order to identify potential de novo miRNA-like small RNAs (milRNAs) that might allow their later detection in the diet. Results pointed to 1 already known and 37 de novo milRNAss. Three milRNAss were selected for RT-qPCR experiments. Precursors and mature milRNAs were found in the edible parts (caps and stipes) validating the predictions carried out in silico. When their potential gene targets were investigated, results pointed that mostly were involved in primary and secondary metabolic regulation. However, when human transcriptome is used as target, the results suggest that they might interfere with important biological processes related with cancer, infectious process and neurodegenerative diseases.