@article{charlton_carbone_tavantzis_cubeta_2008, title={Phylogenetic relatedness of the M2 double-stranded RNA in Rhizoctonia fungi}, volume={100}, ISSN={["0027-5514"]}, DOI={10.3852/07-108R}, abstractNote={Isolates from closely related fungi in the Rhizoctonia species complex were examined for the occurrence of the M2 double-stranded RNA (dsRNA) by amplifying a conserved 1000 nucleotide region of the dsRNA with reverse transcription PCR. The M2 dsRNA was detected in representative isolates belonging to three anastomosis groups (AG) of R. solani (AG-1-IA, AG-4 and AG-6; teleomorph = Thanatephorus) and four AGs of binucleate Rhizoctonia (AGA, AG-F, AG-R and AG-U; teleomorph = Ceratobasidium). Amplified PCR products from the 3′ region of the M2 dsRNA from a representative sample of 12 isolates from eight different AGs were sequenced and subjected to parsimony analysis and coalescent simulations to infer ancestral lineages and to reconstruct the ancestral history of haplotypes. Seven dsRNA haplotypes were inferred from the sample of 12 isolates. One haplotype was composed of only isolates of Ceratobasidium belonging to different AGs. The rooted gene genealogies from coalescent simulations suggested that the ancestral M2 dsRNA haplotype most likely evolved in Thanatephorus (anamorph = R. solani AG-1-IA) and has been acquired recently by isolates of Ceratobasidium. Reconstruction of the ancestral history of haplotypes with a parsimony-based approach that assumes both mutation and recombination suggested that four haplotypes recombined before coalescing to their most recent common ancestor, while three haplotypes coalesced without recombination in the recent past. There was no unique association of haplotype within a specific AG of either Ceratobasidium or Thanatephorus to support co-evolution of the M2 dsRNA within the fungal host. To our knowledge this is the first report of a dsRNA occurring in Ceratobasidium that also is present in Thanatephorus.}, number={4}, journal={MYCOLOGIA}, author={Charlton, Nikki D. and Carbone, Ignazio and Tavantzis, Stellos M. and Cubeta, Marc A.}, year={2008}, pages={555–564} }
 @article{charlton_cubeta_2007, title={Transmission of the M2 double-stranded RNA in Rhizoctonia solani anastomosis group 3 (AG-3)}, volume={99}, ISSN={["1557-2536"]}, DOI={10.3852/mycologia.99.6.859}, abstractNote={Horizontal transmission of the 3.57 kb M2 double-stranded RNA (dsRNA) between mycelia of somatically incompatible isolates of Rhizoctonia solani anastomosis group 3 (AG-3), an economically important pathogen of cultivated plants in the family Solanaceae, was investigated. Nine donor isolates of R. solani AG-3 containing the M2 dsRNA were paired on potato-dextrose agar with each of three different recipient isolates where the M2 dsRNA was absent. Reverse-transcription PCR (RT-PCR) was used to detect horizontal transmission of the M2 dsRNA via hyphal anastomosis from donor to recipient isolates by examining hyphal explants taken 3 cm from the hyphal interaction zone. PCR-RFLP genetic-based markers of two nuclear loci and one mitochondrial locus were used to confirm identity and transmission between donor and recipient isolates of R. solani AG-3. The frequency of transmission observed between 72 pairings of the eight donor and three recipient isolates was approximately 4% of the total pairings, and differences in the phenotype of the recipient isolates after acquisition of the M2 dsRNA via horizontal transmission were observed. To our knowledge this represents the first demonstration of transmission of dsRNA between genetically different individuals of R. solani confirmed with nuclear and mitochondrial markers. These results suggest that transmission can occur between somatically incompatible isolates of R. solani AG-3 but that maintenance of the dsRNA in the recipient isolates was not stable after repeated subculturing on nutrient medium.}, number={6}, journal={MYCOLOGIA}, author={Charlton, Nikki D. and Cubeta, Marc A.}, year={2007}, pages={859–867} }