Complementary functions of two recessive R-genes determine resistance durability of tobacco 'Virgin A Mutant' (VAM) to Potato virus Y

Rodolfo Acosta-Leal, Zhongguo Xiong

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

Tobaccos VAM and NC745 carry the recessive va gene that confers resistance to PVYNN. However, they exhibit different levels of resistance durability. Upon virus inoculation, only NC745 developed sporadic systemic symptoms caused by emerging resistance-breaking variants that easily infected both NC745 and VAM genotypes. To identify the differential host conditions associated with this phenomenon, cellular accumulation, cell-to-cell movement, vascular translocation, and foliar content of PVYNN were comparatively evaluated. Virus cell-to-cell movement was restricted and its transit through the vasculature boundaries was completely blocked in both tobacco varieties. However, an additional defense mechanism operating only in tobacco VAM drastically reduced the in situ cellular virus accumulation. Genetic analyses of hybrid plant progenies indicate that VAM-type resistance was conditioned by at least two recessive genes: va and a newly reported va2 locus. Moreover, segregant plant progenies that restricted virus movement but permitted normal virus accumulation were prone to develop resistance-breaking infections.

Original languageEnglish (US)
Pages (from-to)275-283
Number of pages9
JournalVirology
Volume379
Issue number2
DOIs
StatePublished - Sep 30 2008

Keywords

  • Cytoplasmic inheritance
  • Gene pyramiding
  • Genome-linked protein
  • Pathogenesis
  • Pepper pvr2 gene
  • Picornavirus
  • Protoplast printing
  • Tolerance
  • VPg
  • eIF4E

ASJC Scopus subject areas

  • Virology

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