Mycoreovirus 1 S4-coded protein is dispensable for viral replication but necessary for efficient vertical transmission and normal symptom induction.
Rearrangements of two segments, S6 and S10, of Mycoreovirus 1 (MyRV1), a member of the family Reoviridae, were previously shown to be induced at a high rate by the multifunctional protein p29 encoded by a distinct ssRNA virus, the prototype hypovirus CHV1-EP713 (Sun and Suzuki, RNA 14, 2557-2571, 2008). Here we report the occurrence of rearrangements of MyRV1 S4, albeit at a very low frequency, in the absence of CHV1 p29, resulting in internal 80-90% deletions of the open reading frame (ORF) in S4. Comparative analyses of fungal strains infected by wild-type MyRV1 and its variants carrying rearrangements of S4, S4 plus S10 and S10 indicated that S4-encoded VP4, like VP10, is non-essential for virus replication but required for efficient vertical transmission and symptom expression caused by MyRV1. This is the first example of a reovirus variant that carries deletions of over 75% of the ORFs in two genome segments and is still replication-competent.
Eusebio-Cope
Ana
A
Agrivirology Laboratory, Research Institute for Bioresources, Okayama University, Kurashiki, Okayama 710-0046, Japan. anacope2004@yahoo.com
Sun
Liying
L
Hillman
Bradley I
BI
Suzuki
Nobuhiro
N
D001203:Ascomycota / Q000821:virology*; D016366:Open Reading Frames; D011995:Recombination, Genetic; D012087:Reoviridae / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D017384:Sequence Deletion; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology*; D037521:Virulence Factors / Q000235:genetics / Q000502:physiology*; D014779:Virus Replication
D014764:Viral Proteins; D037521:Virulence Factors