EXA1, a GYF domain protein, is responsible for loss-of-susceptibility to plantago asiatica mosaic virus in Arabidopsis thaliana

Masayoshi Hashimoto, Yutaro Neriya, Takuya Keima, Nozomu Iwabuchi, Hiroaki Koinuma, Yuka Hagiwara-Komoda, Kazuya Ishikawa, Misako Himeno, Kensaku Maejima, Yasuyuki Yamaji, Shigetou Namba

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

One of the plant host resistance machineries to viruses is attributed to recessive alleles of genes encoding critical host factors for virus infection. This type of resistance, also referred to as recessive resistance, is useful for revealing plant–virus interactions and for breeding antivirus resistance in crop plants. Therefore, it is important to identify a novel host factor responsible for robust recessive resistance to plant viruses. Here, we identified a mutant from an ethylmethane sulfonate (EMS)-mutagenized Arabidopsis population which confers resistance to plantago asiatica mosaic virus (PlAMV, genus Potexvirus). Based on map-based cloning and single nucleotide polymorphism analysis, we identified a premature termination codon in a functionally unknown gene containing a GYF domain, which binds to proline-rich sequences in eukaryotes. Complementation analyses and robust resistance to PlAMV in a T-DNA mutant demonstrated that this gene, named Essential for poteXvirus Accumulation 1 (EXA1), is indispensable for PlAMV infection. EXA1 contains a GYF domain and a conserved motif for interaction with eukaryotic translation initiation factor 4E (eIF4E), and is highly conserved among monocot and dicot species. Analysis using qRT-PCR and immunoblotting revealed that EXA1 was expressed in all tissues, and was not transcriptionally responsive to PlAMV infection in Arabidopsis plants. Moreover, accumulation of PlAMV and a PlAMV-derived replicon was drastically diminished in the initially infected cells by the EXA1 deficiency. Accumulation of two other potexviruses also decreased in exa1-1 mutant plants. Our results provided a functional annotation to GYF domain-containing proteins by revealing the function of the highly conserved EXA1 gene in plant–virus interactions.

Original languageEnglish
Pages (from-to)120-131
Number of pages12
JournalPlant Journal
Volume88
Issue number1
DOIs
Publication statusPublished - Oct 1 2016
Externally publishedYes

Keywords

  • Arabidopsis thaliana
  • EXA1
  • GYF domain
  • plantago asiatica mosaic virus
  • plant–virus interactions
  • Potexvirus
  • recessive resistance

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

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