title: Rice dwarf viruses with dysfunctional genomes generated in plants are filtered out in vector insects: implications for the origin of the virus.
abstract: Rice dwarf virus (RDV), with 12 double-stranded RNA (dsRNA) genome segments (S1 to S12), replicates in and is transmitted by vector insects. The RDV-plant host-vector insect system allows us to examine the evolution, adaptation, and population genetics of a plant virus. We compared the effects of long-term maintenance of RDV on population structures in its two hosts. The maintenance of RDV in rice plants for several years resulted in gradual accumulation of nonsense mutations in S2 and S10, absence of expression of the encoded proteins, and complete loss of transmissibility. RDV maintained in cultured insect cells for 6 years retained an intact protein-encoding genome. Thus, the structural P2 protein encoded by S2 and the nonstructural Pns10 protein encoded by S10 of RDV are subject to different selective pressures in the two hosts, and mutations accumulating in the host plant are detrimental in vector insects. However, one round of propagation in insect cells or individuals purged the populations of RDV that had accumulated deleterious mutations in host plants, with exclusive survival of fully competent RDV. Our results suggest that during the course of evolution, an ancestral form of RDV, of insect virus origin, might have acquired the ability to replicate in a host plant, given its reproducible mutations in the host plant that abolish vector transmissibility and viability in nature.
authors.affiliation: Peking-Yale Joint Center for Plant Molecular Genetics and Agrobiotechnology National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China
authors.forename: Yingying
authors.initials: Y
authors.lastname: Pu
authors.forename: Akira
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Moriyasu
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Tomaru
authors.forename: Yan
authors.initials: Y
authors.lastname: Jin
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Suga
authors.forename: Kyoji
authors.initials: K
authors.lastname: Hagiwara
authors.forename: Fusamichi
authors.initials: F
authors.lastname: Akita
authors.forename: Takumi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Osamu
authors.initials: O
authors.lastname: Netsu
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Suzuki
authors.forename: Tamaki
authors.initials: T
authors.lastname: Uehara-Ichiki
authors.forename: Takahide
authors.initials: T
authors.lastname: Sasaya
authors.forename: Taiyun
authors.initials: T
authors.lastname: Wei
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Omura
mesh_terms: D000818:Animals; D002460:Cell Line; D018389:Codon, Nonsense; D004199:Disease Vectors; D007313:Insecta / Q000821:virology*; D012275:Oryza / Q000821:virology*; D010935:Plant Diseases / Q000821:virology*; D012087:Reoviridae / Q000235:genetics* / Q000472:pathogenicity*; D012641:Selection, Genetic; D014764:Viral Proteins / Q000235:genetics
chemical_list: D018389:Codon, Nonsense; D014764:Viral Proteins