Silencing of SDN1 elevated BaMV vsiRNA level and decreased BaMV RNA accumulation in N. benthamiana, indicating that NbAGO10 might recruit SDN1 for BaMV vsiRNA degradation. A host enzyme, small RNA degrading nuclease 1 (SDN1), also was found to interact with NbAGO10 on in vivo pull-down assay. In addition, overexpression of NbAGO10 decreased BaMV vsiRNA accumulation. Transient overexpression of NbAGO10 increased BaMV RNA accumulation, but with co-expression of NbAGO1, BaMV RNA accumulation was reduced, which suggests that NbAGO10 may have competed with NbAGO1 for sequestering BaMV vsiRNA and prevented the formation of RNA-induced silencing complexes. Immunoprecipitation assay revealed BaMV virus-derived small interfering RNAs (vsiRNAs) in NbAGO10 complexes.By using a virus-induced gene silencing technique, it was found that Nicotiana benthamiana AGO1 restricted Bamboo mosaic virus (BaMV) accumulation, but NbAGO10, the closest paralog of NbAGO1, positively regulated BaMV accumulation.The number of AGO family members involved varies depending on the plant species and they play distinct or sometimes redundant roles in antiviral defense.

Argonaute proteins (AGOs) are the key players in RNA silencing. RNA silencing is a major defense mechanism against invading viruses in plants.

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