The virological model plant, Nicotiana benthamiana expresses a single functional RDR6 homeolog

Abstract

The RNA dependent RNA polymerase, RDR6 is involved in a variety of processes including the biogenesis of endogenous regulatory small RNAs, maintaining post-transcriptional gene silencing of transgenes and establishing efficient antiviral RNA silencing. In the virological model plant, Nicotiana benthamiana, functional studies of RDR6 has so far only been depended on RNAi based methodologies. These techniques however have inherent limitations, especially in the context of antiviral RNA silencing. To overcome this issue, we created rdr6 mutant N. benthamiana by the CRISPR/Cas9 genome editing system. Using the mutant, most of the proposed functions of RDR6 was confirmed. Additionally, the rdr6 N. benthamiana plant recapitulated closely the phenotype of the equivalent Arabidopsis mutant. In summary, the rdr6 N. benthamiana described here may be employed as a model system not only for the better understanding of the role of RDR6 in pathogen elicited immune responses but in various developmental processes as well.

Keywords: CRISPR/Cas9; Nicotiana benthamiana; RDR6; RNA silencing; Small RNA; Virus.