Next Generation Sequencing Facilitates Quantitative Analysis of mock and tobacco ratle virus (TRV) Arabidopsis inflorescences Transcriptome [RNA-Seq]

Purpose: The goal of this study is to compare the transcriptome profilling (RNA-seq) of inflorescences infected with tobacco ratle virus (TRV) to mock inoculated inflorescences (negative controls), in Arabidopsis plants Methods: Inflorescences of systemically TRV infected or mock-inoculated plants were collected from more than 40 independent Arabidopsis plants, at 14 days post-inoculation (dpi). TRV and mock mRNA profiles were generated by deep sequencing by Illumina HiSeq 2000. The sequence reads that passed quality filters (SOAPnuke) were analysed by Burrows-Wheeler (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. Genes and isoforms were quantified by RSEM sofware package. qRT-PCR validation was performed using TaqMan and SYBR Green assays. Results: Here we report a significant repression of DNA methylation genes in inflorescences of Arabidopsis plants infected with Tobacco rattle virus (TRV) that coincides with dynamic changes in methylation at the whole genome level. Arabidopsis mutants deficient in DNA methylation were more resistant to this virus in early colonized tissues but more susceptible at later time points of infection, indicating that DNA methylation was critical to control both proliferation and antiviral defense. We found that TRV interference with DNA methylation leads to changes in the methylation and trancriptional status of transposable elements (TEs), including TEs located in the promoter of disease resistance genes that were significantly repressed in plants exposed to TRV. Activation of both TEs and their nearby disease resistance genes was altered in a range of hypo- and hyper-methylated Arabidopsis mutants, indicating that perturbations in DNA methylation contributes to modulate their expression in infected plants. Conclussion: Our study showed that TRV interferes with DNA methylation to alter the transcriptional silencing of TEs, which in turn compromises the expression of neighboring disease resistance genes. Overall design: TRV and mock mRNA profiles were generated from Arabidopsis inflorescences by deep sequencing with Illumina HiSeq 2000.

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Diezma-Navas L, Pérez-González A, Artaza H, Alonso L, Caro E, Llave C, Ruiz-Ferrer V