sRNAseq-data

We have previously shown that the beneficial soilborne endophytic fungus Fusarium solani strain K (FsK) translocates small RNAs (sRNAs) to its host Nicotiana benthamiana leading to systemic silencing of a reporter gene. Here, we aimed to address the mechanistic details of this sRNA-based interaction. In the systemically silenced plants, we performed sRNA sequencing in root and leaf tissues. Our findings revealed that the translocated fungal sRNAs induced transitivity and secondary sRNA production already in the root tissues. The secondary sRNA pattern did not differ between the root and leaf tissues. Secondary sRNAs were mainly of 22-24 nt in size, with the conspicuous absence of 21-nt sRNAs. Importantly, systemic silencing and RNA-directed DNA methylation (RdDM) could be induced only in an intronless gene, but not in an intron-containing gene or in an intronless gene at RNA-DEPENDENT RNA POLYMERASE 6 (RDR6) knockout background. Overall, our data suggest that FsK-induced silencing in the host requires RDR6-mediated transitivity and amplification of silencing signals and, in this view, not all genes are equally efficient targets for FsK-induced silencing.