Unravelling the involvement of cilevirus p32 protein in the viral transport

Sci Rep. 2021 Feb 3;11(1):2943. doi: 10.1038/s41598-021-82453-4.

Abstract

Citrus leprosis (CL) is a severe disease that affects citrus orchards mainly in Latin America. It is caused by Brevipalpus-transmitted viruses from genera Cilevirus and Dichorhavirus. Currently, no reports have explored the movement machinery for the cilevirus. Here, we have performed a detailed functional study of the p32 movement protein (MP) of two cileviruses. Citrus leprosis-associated viruses are not able to move systemically in neither their natural nor experimental host plants. However, here we show that cilevirus MPs are able to allow the cell-to-cell and long-distance transport of movement-defective alfalfa mosaic virus (AMV). Several features related with the viral transport were explored, including: (i) the ability of cilevirus MPs to facilitate virus movement on a nucleocapsid assembly independent-manner; (ii) the generation of tubular structures from transient expression in protoplast; (iii) the capability of the N- and C- terminus of MP to interact with the cognate capsid protein (p29) and; (iv) the role of the C-terminus of p32 in the cell-to-cell and long-distance transport, tubule formation and the MP-plasmodesmata co-localization. The MP was able to direct the p29 to the plasmodesmata, whereby the C-terminus of MP is independently responsible to recruit the p29 to the cell periphery. Furthermore, we report that MP possess the capacity to enter the nucleolus and to bind to a major nucleolar protein, the fibrillarin. Based on our findings, we provide a model for the role of the p32 in the intra- and intercellular viral spread.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Capsid Proteins / metabolism*
  • Citrus / virology*
  • Mites / virology
  • Nucleocapsid / metabolism
  • Plant Diseases / virology*
  • Plant Viral Movement Proteins / metabolism*
  • Plant Viruses / metabolism*
  • Plant Viruses / pathogenicity
  • Protoplasts / metabolism
  • Protoplasts / virology

Substances

  • Capsid Proteins
  • Plant Viral Movement Proteins