Cloned Phaeodactylum tricornutum DICER (DCR), ARGONAUTE (AGO), RNA-dependent RNA polymerase (RDR) genes and sequencing of P. tricornutum DICER-KnockOut (DCR-KO) sRNA and mRNA transcriptomes, as well as Histone modification landscape (ChIP-Seq).. Phaeodactylum tricornutum RNAi core genes and sequencing data of transcriptomes generated from DICER-KnockOut mutants

Diatoms are unicellular Stramenopile algae responsible for a quarter of the global primary productivity. RNA interference (RNAi) is a mechanism mediated by small RNAs (sRNAs) that regulates gene expression. Previous studies in the model diatom species Phaeodactylum tricornutum reported the presence of small RNAs mapped to epigenetically repressed transposable elements (TE) and genes suggesting the presence of RNA-directed DNA methylation pathway. However, the enzyme responsible for sRNA biogenesis and their physiological role are unknown. In this study, we cloned and sequenced the RNAi key-effectors found in Phaeodactylum tricornutum: DICER (DCR), ARGONAUTE (AGO) and RNA-dependent RNA polymerase (RDR) genes. We generated P. tricornutum DCR-KnockOut lines (DCR-KO) by CRISPR-Cas9 mutagenesis and then sequenced and characterized their mRNA and sRNA transcriptomes. Our study unveiled DCR function in a marine eukaryotic phytoplankton shedding light on the evolution of RNAi in eukaryotes.