Encapsulated and non-encapsulated double-stranded RNA (dsRNA) has been reported in the plant pathogenic fungi Rhizoctonia solani. DsRNA is implicated in transmissible cytoplasmic hypovirulence which reduces the pathogenic fitness of the fungus. In the current research project, previously cloned viral dsRNA belonging to three R. solani isolates were analyzed for the presence of RNA-dependent, RNA polymerase and capsid genes. The three isolates selected have varying degrees of pathogenicity and belong to the same anastomosis group (AG-13). For each cloned dsRNA fragment sequence, the open reading frames (ORF’s) and the translated protein products were aligned with the known dsRNA sequences and respective proteins through NCBI blast(n) and blast(p). Additionally, DELTA-blast and Conserved Domain database (CDD) searches were undertaken for these sequences. The cloned viral sequences were aligned for homology within and among isolates of the same AG. The blast(p) alignments indicated each sequence contained at least one ORF with significant homology to a known R. solani dsRNA coat protein, with low e value scores. The DELTA-blast searches for the homologous ORFs yielded multiple “hits” with viral coat proteins from red clover and white clover cryptic viruses. No putative conserved domains were detected for these ORFs. Additionally, ORF’s in a second reading frame were found with high homology to yeast Rba50p proteins and contained the conserved RPAP1_C domain. Aligned ORF maps for ORFs have translated sequences with significant homology to those of known genes. Sequences have high homology to known mycoviral capsid proteins, Rba50p protein, and all such translated sequences contain the conserved RPAP1_C domain. Alignments of ORF’s showed a high degree of homology among all three isolates. For the putative CP ORFs, nucleotide CLUSTALW alignments showed 534/1687 conserved sites and 718/1687 variable sites. Results from methods of cloning, restriction enzyme digestion, and sequence analysis will be presented.
Sequence Analysis of Double-Stranded (DS) RNA Genome Cloned from the Plant Pathogenic Isolate of Rhizoctonia solani
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