DNA and RNA viruses infection in plant: two different ways to dynamically change the host's epigenetic profile

The establishment and maintenance of DNA methylation are relatively well understood whereas little is known about their dynamics and biological relevance in innate immunity [1-2]. In plants, modulation of DNA methylation might be an effective mechanism to regulate gene expression in response to abiotic and biotic stresses. Recent evidences from large-scale epigenomic approaches indicate that dynamic DNA methylation changes are not limited to gene imprinting but can regulate the plant's immune system in response to pathogens. In plants, virus infections trigger the expression of non-coding small RNAs (smRNAs) by also influencing the epigenetic status of the host genome; however, the involvement of DNA methylation in regulation of plant immune system in response to virus infection has not been so far investigated. In this context, we are carrying out a study aiming to elucidate the impact of DNA and RNA virus infections on genomic DNA methylation in plants, and their correlation with also the expression of smallRNA, by integrating the analysis of multiple "omics" datasets obtained by using next-generation sequencing technologies. In this paper we present the results of the analysis on the methylation modifications induced by the viruses infection on the whole genome and on coding and non-coding gene regions.