Inhibition of tobacco mosaic virus movement by expression of an actin-binding protein

Plant Physiol. 2009 Apr;149(4):1810-23. doi: 10.1104/pp.108.133827. Epub 2009 Feb 13.

Abstract

The tobacco mosaic virus (TMV) movement protein (MP) required for the cell-to-cell spread of viral RNA interacts with the endoplasmic reticulum (ER) as well as with the cytoskeleton during infection. Whereas associations of MP with ER and microtubules have been intensely investigated, research on the role of actin has been rather scarce. We demonstrate that Nicotiana benthamiana plants transgenic for the actin-binding domain 2 of Arabidopsis (Arabidopsis thaliana) fimbrin (AtFIM1) fused to green fluorescent protein (ABD2:GFP) exhibit a dynamic ABD2:GFP-labeled actin cytoskeleton and myosin-dependent Golgi trafficking. These plants also support the movement of TMV. In contrast, both myosin-dependent Golgi trafficking and TMV movement are dominantly inhibited when ABD2:GFP is expressed transiently. Inhibition is mediated through binding of ABD2:GFP to actin filaments, since TMV movement is restored upon disruption of the ABD2:GFP-labeled actin network with latrunculin B. Latrunculin B shows no significant effect on the spread of TMV infection in either wild-type plants or ABD2:GFP transgenic plants under our treatment conditions. We did not observe any binding of MP along the length of actin filaments. Collectively, these observations demonstrate that TMV movement does not require an intact actomyosin system. Nevertheless, actin-binding proteins appear to have the potential to exert control over TMV movement through the inhibition of myosin-associated protein trafficking along the ER membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / drug effects
  • Actin Cytoskeleton / metabolism
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / metabolism
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology
  • Cytoskeleton / drug effects
  • Cytoskeleton / virology
  • Golgi Apparatus / drug effects
  • Golgi Apparatus / metabolism
  • Golgi Apparatus / virology
  • Green Fluorescent Proteins / metabolism
  • Microfilament Proteins / metabolism*
  • Models, Biological
  • Movement / drug effects
  • Movement / physiology*
  • Myosins / metabolism
  • Plant Leaves / cytology
  • Plant Leaves / drug effects
  • Plant Leaves / virology
  • Plant Viral Movement Proteins / metabolism
  • Plants, Genetically Modified
  • Protein Transport / drug effects
  • Recombinant Fusion Proteins / metabolism
  • Subcellular Fractions / drug effects
  • Subcellular Fractions / metabolism
  • Thiazolidines / pharmacology
  • Tobacco / cytology
  • Tobacco / drug effects
  • Tobacco / genetics
  • Tobacco / virology*
  • Tobacco Mosaic Virus / drug effects
  • Tobacco Mosaic Virus / physiology*

Substances

  • ATFIM1 protein, Arabidopsis
  • Arabidopsis Proteins
  • Bridged Bicyclo Compounds, Heterocyclic
  • Microfilament Proteins
  • Plant Viral Movement Proteins
  • Recombinant Fusion Proteins
  • Thiazolidines
  • Green Fluorescent Proteins
  • Myosins
  • latrunculin B