Project description:We focused our analyses on the description of viral (CMV-?2b) and, based on genetic and molecular evidence, classified them and discussed their relevance in antiviral defense. Small RNAs from Arabidopsis plants from different genetic backgrounds infected with (CMV-?2b) were sequenced before or after immunoprecipitation with antibodies against key proteins involved in antiviral defense.
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:Belonging to the Carmovirus family, Turnip crinkle virus (TCV) is a positive-strand RNA virus that can infect Arabidopsis. Most Arabidopsis ecotypes are highly susceptible to TCV, except for the TCV resistant line Di-17 derived from ecotype Dijon. Previous studies showed that many of the stress related genes have changed significantly after TCV infection. Besides the virus-triggered genes, small RNAs also play critical roles in plant defense by triggering either transcriptional and/or post-transcriptional gene silencing. In this study, TCV-infected wildtype Arabidopsis thaliana and dcl1-9 mutant plants were subjected to transcriptome and small RNA analysis to investigate the role of DCL1 in virus defense network.
Project description:Belonging to the Carmovirus family, Turnip crinkle virus (TCV) is a positive-strand RNA virus that can infect Arabidopsis. Most Arabidopsis ecotypes are highly susceptible to TCV, except for the TCV resistant line Di-17 derived from ecotype Dijon. Previous studies showed that many of the stress related genes have changed significantly after TCV infection. Besides the virus-triggered genes, small RNAs also play critical roles in plant defense by triggering either transcriptional and/or post-transcriptional gene silencing. In this study, TCV-infected wildtype Arabidopsis thaliana and dcl1-9 mutant plants were subjected to transcriptome and small RNA analysis to investigate the role of DCL1 in virus defense network.
Project description:To determine the extent to which the major small RNA pathways functions across the Arabidopsis thaliana genome, small RNA populations from several tissues of wild-type (wt) and mutant plants were amplified by RT-PCR and sequenced using high-throughput 454 sequencing technology. Keywords: small RNAs, high-throughput sequencing
Project description:The cucumber mosaic virus (CMV) 2b counter-defense protein disrupts plant antiviral mechanisms mediated by RNA silencing and salicylic acid (SA). Using NASC ATH-1 microarrays to investigate defensive gene expression in 2b-transgenic Arabidopsis thaliana plants we found that, surprisingly, 2b inhibited expression of few SA-regulated genes and in some instances enhanced the effect of SA on certain genes. Strikingly, the 2b protein inhibited changes in the expression of 90% of genes regulated by jasmonic acid (NASCARRAYS-415: Lewsey et al. Molec. Plant-Microbe Interact. vol. 23, in press). We will extend this work to understand the effects of the 2b protein on plant gene expression during an authentic viral infection. By comparing the effects on the transcriptome of infection by wild-type CMV and the 2b gene deletion mutant, CMVâËâ 2b, we will reveal not only the influence of the 2b protein but also the effects of its interactions with other viral gene products (and the process of infection itself), on the host transcriptome.