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
Project description:The discovery of N6-methyladenine (6mA), typically found in prokaryotic DNA, in eukaryotic genomes, has revolutionized epigenetics. Here, we show that symmetric 6mA is essential in the early diverging fungus Rhizopus microsporus, as the absence of the MT-A70 complex (MTA1c) responsible for this modification results in a lethal phenotype. 6mA is present in 70% of the genes, correlating with the presence of H3K4me3 and H2A.Z in open euchromatic regions. This modification is found predominantly in nucleosome linker regions, influencing the nucleosome positioning around the transcription start sites of highly expressed genes. Controlled downregulation of MTA1c results in a reduction of symmetric 6mA sites affecting nucleosome positioning and histone modifications, leading to altered gene expression, which is likely the cause of lethality. Our study highlights the indispensable role of the DNA 6mA in a multicellular organism and delineates the mechanisms through which this epigenetic mark regulates gene expression in a eukaryotic genome
