title: Molecular characterisation of an endornavirus from Rhizoctonia solani AG-3PT infecting potato.
abstract: Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is a soil-borne plant pathogenic fungus that has a broad host range, including potato. In this study, the double-stranded RNA (dsRNA) profiles were defined for 39 Rhizoctonia solani isolates representative of two different anastomosis groups (AGs) associated with black scurf of potato in New Zealand. A large dsRNA of c. 12 kb-18 kb was detected in each of the isolates, regardless of AG or virulence on potato. Characterisation of the large dsRNA from R. solani AG-3PT isolate RS002, using random amplification of total dsRNA and analyses of overlapping cDNA sequences, resulted in the assembly of a consensus sequence of 14 694 nt. A single, large open reading frame was identified on the positive strand of the assembled sequence encoding a putative polypeptide of at least 4893 amino acids, with a predicted molecular mass of 555.6 kDa. Conserved domains within this polypeptide included those for a viral methyltransferase, a viral RNA helicase 1 and an RNA-dependent RNA polymerase. The domains and their sequential organisation revealed the polyprotein was very similar to those encoded by dsRNA viruses of the genus Endornavirus, in the family Endornaviridae. This is the first report of an endornavirus in R. solani, and thus the putative virus is herein named Rhizoctonia solani endornavirus - RS002 (RsEV-RS002). Partial characterisation of the large dsRNAs in five additional AG-3PT isolates of R. solani also identified them as probable endornaviruses, suggesting this family of viruses is widespread in R. solani infecting potato. The ubiquitous nature of endornaviruses in this plant pathogen implies they may have an important, but yet uncharacterised, role in R. solani.
authors.affiliation: Bio-Protection Research Centre, PO Box 85084, Lincoln University 7647, Canterbury, New Zealand; The New Zealand Institute for Plant & Food Research Limited, PB 4704, Christchurch, New Zealand. Electronic address: subhadas_geneticscal@yahoo.co.in.
authors.forename: Subha
authors.initials: S
authors.lastname: Das
authors.affiliation: Bio-Protection Research Centre, PO Box 85084, Lincoln University 7647, Canterbury, New Zealand; The New Zealand Institute for Plant & Food Research Limited, PB 4704, Christchurch, New Zealand. Electronic address: richard.falloon@plantandfood.co.nz.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Falloon
authors.affiliation: Bio-Protection Research Centre, PO Box 85084, Lincoln University 7647, Canterbury, New Zealand; Marrone Bio Innovations, Inc., 2121 Second St, Suite 107B Davis, CA 95618, USA. Electronic address: astewart@marronebio.com.
authors.forename: Alison
authors.initials: A
authors.lastname: Stewart
authors.affiliation: Bio-Protection Research Centre, PO Box 85084, Lincoln University 7647, Canterbury, New Zealand; The New Zealand Institute for Plant & Food Research Limited, PB 4704, Christchurch, New Zealand. Electronic address: andrew.pitman@plantandfood.co.nz.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Pitman
mesh_terms: D016000:Cluster Analysis; D017124:Conserved Sequence; D023061:Gene Order; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009520:New Zealand; D016366:Open Reading Frames; D010802:Phylogeny; D010935:Plant Diseases / Q000821:virology; D012328:RNA Viruses / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D012367:RNA, Viral / Q000235:genetics; D012232:Rhizoctonia / Q000302:isolation & purification / Q000821:virology*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D011198:Solanum tuberosum / Q000821:virology*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D012367:RNA, Viral; D014764:Viral Proteins
keywords: Double-stranded RNA; Methyltransferase; RNA helicase 1; RNA-dependent RNA polymerase; Virulence