Small RNA bidirectional crosstalk during the interaction between Zymoseptoria tritici and wheat

Eukaryotic sRNAs are short regulatory non-coding RNAs that induce silencing of target genes at the transcriptional or post-transcriptional level. This conserved eukaryotic mechanism is known as RNA interference (RNAi), and plays important roles in maintaining RNA stability, RNA processing, the response to biotic stresses and the regulation of morphological and developmental processes. The RNAi mechanism is present in all fungal families, although most of our knowledge about RNAi pathways in fungi comes from studies on model fungal species, in which sRNAs play important roles in the regulation of developmental processes. However, the effects of sRNAs are not limited to the organism where they are produced and they can sometimes extend to interacting species, including species that come from different kingdoms yet are able to alter each other`s gene expression, a phenomenon known as cross-kingdom RNAi. In this study we explored the small RNAs produced during the interaction between wheat and the important wheat pathogen Zymoseptoria tritici. We combined small RNA sequencing, degradome sequencing, and dual RNA sequencing of both pathogen and host at different stages of the infection cycle to identify small RNAs from both pathogen and host as well as their gene targets in both organisms. Our results suggest that a small RNA bidirectional crosstalk is taking place during the interaction between Z. tritici and wheat, therefore contributing to our understanding of this complex interaction.