Project description:Cytosine methylation is a conserved base modification, but explanations for its interspecific variation remain elusive. Only through taxonomic sampling of disparate groups can unifying explanations for interspecific variation be thoroughly tested. Here we leverage phylogenetic resolution of cytosine DNA methyltransferases (DNA MTases) and genome evolution to better understand widespread interspecific variation across 40 diverse fungal species. DNA MTase genotypes have diversified from the ancestral DNMT1+DNMT5 genotype through numerous loss events, and duplications, whereas, DIM-2 and RID-1 are more recently derived in fungi. Methylation is typically enriched at intergenic regions, which includes repeats and transposons. Unlike certain Insecta and Angiosperm species, Fungi lack canonical gene body methylation. Some fungi species possess large clusters of contiguous methylation encompassing many genes, repetitive DNA and transposons, and are not ancient in origin. Broadly, methylation is partially explained by DNA MTase genotype and repetitive DNA content. Basidiomycota on average have the highest level of methylation, and repeat content, compared to other phyla. However, exceptions exist across Fungi. Other traits, including DNA repair mechanisms, might contribute to interspecific methylation variation within Fungi. Our results show mechanism and genome evolution are unifying explanations for interspecific methylation variation across Fungi.
Project description:In this work, we have used deep sequencing to study the viral small RNA (vsiRNA) populations from different mycoviruses infecting field isolates of Botrytis spp. The mycoviruses under study belong to different genera and species and have different type of genome (dsRNA, (+)ssRNA, and (-)ssRNA). In general, vsiRNAs derived from mycoviruses are mostly of 21, 20 and 22 nucleotides in length, possess sense or antisense orientation either in a similar ratio or with a predominance of sense polarity depending on the virus species, have predominantly U at their 5' end, and are unevenly distributed along the viral genome showing conspicuous hotspots of vsiRNA accumulation. These characteristics reveal striking concomitances with vsiRNAs produced by plant viruses suggesting similar pathways of viral targeting in plants and fungi