Genome-wide Identification and characterization of circular RNAs in the rice blast fungus Magnaporthe oryzae

Numerous circRNAs have been identified in different organisms, but little attention has been addressed on fungal circRNAs. Here, we identified a total of 8,848 circRNAs from the model plant pathogenic fungus M. oryzae. 5,840 circRNAs were identified from mycelium, 2,721 circRNAs from conidium, while only 287 circRNAs from both tissues. This indicated that most of the M. oryzae circRNAs were specifically expressed in mycelium or in conidium. Parental genes of circRNAs in mycelium were enriched in basic metabolisms required for normal growth, while in conidium, they were enriched in biogenesis of storages potentially used for infection. M. oryzae circRNAs could also bind to miRNAs, suggesting they may also function as sponges in fungi. This study suggested M. oryzae circRNAs could play important roles in regulation of growth and development.