RDR1

RDR1, or RNA-dependent RNA polymerase 1, is a gene encoding an enzyme in the RNA silencing pathway of plants, most notably in the model species Arabidopsis thaliana. As part of the plant family of RNA-dependent RNA polymerases (RdRPs), RDR1 synthesizes complementary RNA from viral or aberrant RNA templates to generate double-stranded RNA. This dsRNA is processed by Dicer-like enzymes into small interfering RNAs that guide Argonaute proteins to silence targeted RNA, contributing to antiviral defense and transposon control.

RDR1 functions alongside other plant RdRPs, such as RDR2 and RDR6, with overlapping but distinct roles in RNA silencing. Its expression is upregulated in response to pathogen attack and during salicylic acid signaling, with transcripts detected in multiple tissues. Experimental mutations in RDR1 can alter plant susceptibility to viruses and influence the efficiency of systemic RNA silencing, underscoring its role in both local and, in some contexts, systemic defense responses.

Evolutionarily, RDR1 is part of a conserved family of RNA-dependent RNA polymerases found across land plants, often exhibiting lineage-specific diversification. In addition to its biological role, the acronym RDR1 can refer to other, unrelated topics in different domains (for example, Red Dead Redemption 1, a 2010 video game). The biological RDR1 described here is distinct from those uses. See also RDR2, RDR6, RNA interference, and plant antiviral defense.