title: The 2b protein of Asparagus virus 2 functions as an RNA silencing suppressor against systemic silencing to prove functional synteny with related cucumoviruses.
abstract: Asparagus virus 2 (AV-2) is a member of the genus Ilarvirus in the family Bromoviridae. We cloned the coat protein (CP) and the 2b protein (2b) genes of AV-2 isolates from asparagus plants from various regions and found that the sequence for CP and for 2b was highly conserved among the isolates, suggesting that AV-2 from around the world is almost identical. We then made an AV-2 infectious clone by simultaneous inoculation with in vitro transcripts of RNAs 1-3 of AV-2 and in vitro-synthesized CP, which is necessary for initial infection. Because 2b of cucumoviruses in Bromoviridae can suppress systemic silencing as well as local silencing, we analyzed whether there is functional synteny of 2b between AV-2 and cucumovirus. Using the AV-2 infectious clone, we here provided first evidence that Ilarvirus 2b functions as an RNA silencing suppressor; AV-2 2b has suppressor activity against systemic silencing but not local silencing.
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Kita 9 Nishi9, Kita-ku, Sapporo, Japan. hana@res.agr.hokudai.ac.jp
authors.forename: Hanako
authors.initials: H
authors.lastname: Shimura
authors.forename: Chikara
authors.initials: C
authors.lastname: Masuta
authors.forename: Naoto
authors.initials: N
authors.lastname: Yoshida
authors.forename: Kae
authors.initials: K
authors.lastname: Sueda
authors.forename: Masahiko
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D027761:Asparagus Plant / Q000276:immunology / Q000821:virology; D003001:Cloning, Molecular; D017124:Conserved Sequence; D015967:Gene Expression Regulation, Viral; D054884:Host-Pathogen Interactions; D019179:Ilarvirus / Q000235:genetics / Q000254:growth & development* / Q000276:immunology* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D034622:RNA Interference; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000378:metabolism*; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication
chemical_list: D012367:RNA, Viral; D014764:Viral Proteins; D037521:Virulence Factors