Project description:We investigated the role of A. thaliana RDRs in the RNAi-mediated viral immunity by using a mutant of cucumber mosaic virus (CMV) that does not express the VSR protein 2b. CMV contains three positive-strand genomic RNAs and the 2b protein encoded by RNA2 is essential for infection by suppressing antiviral silencing initiated by either DCL4 or DCL2. Our results demonstrate an essential role for the amplification of viral siRNAs by either RDR1 or RDR6 in antiviral silencing. Further analyses, including Illumina sequencing of more than 3.5 million viral siRNAs, indicated target specificity of the two antiviral RDRs.
Project description:This research uses consecutive generations of two independent mutation accumulation (MA) lines in model organism A. thaliana to understand transgenerational stability of epialleles via self-fertilization. With whole-genome bisulfite sequencing, regions of instability were identified and quantified. The vast majority of the methylated genome is stably inherited to offspring and the identified unstable regions do not change frequently between generations. Additionally, an epigenetic cross of two MA lines was created to understand inheritance patterns of epialleles via outcrossing in the absence of genetic variation. Whole-genome bisulfite sequencing was used to predict epigenotype of the offspring without single nucleotide polymorphisms. In regions of differential methylation between the parents, about half of regions show predictable inheritance.