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RNA virome of two important phytopathogenic fungi

Nina Aboughanem-Sabanadzovic: Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University

<div>Fifty five isolates of <em>Rhizoctonia</em> spp and <em>Macrophomina phaseolina,</em> two important and polyphagous phytopathogenic fungi collected from agronomic crops (i.e. corn, soybean, wheat, peanut) and turfgrasses in Mississippi, were submitted to dsRNA extraction and subsequent custom-based cDNA library construction and Illumina sequencing at the University of Illinois. Results of this investigation showed presence of high molecular weight dsRNA molecules, an indication indication of on-going infections by RNA viruses, in majority of examined isolates of both fungi. Presence of certain viruses was confirmed by transmission electron microscopy observation of purified preparations from dsRNA-containing fungal isolates. Computer-based assembly of 2X250 pair-end reads resulted in numerous contigs varying from several hundred to 17 thousands nucleotides. Analyses revealed presence of numerous previously reported mycoviruses in both hosts. Nevertheless, in this study we also discovered dozens of new viruses belonging to recognized genera and families of mycoviruses with dsRNA and ssRNA genomes (either positive- or negative-sense), or those representing new taxa. Effects of theses viruses is yet to be fully understood; however some of them resulted associated with phenotypic changes in their respective hosts. Finally, significant number of ORF-containing sequences did match currently available data in GenBank, suggestive of the expanding mycovirus diversity.</div>