3 years ago

The Torradovirus-specific RNA2-ORF1 protein is necessary for plant systemic infection

M. Vallino, M. Turina, I Ferriol, M. Ciuffo, B.W. Falk, E. J. Zamora-Macorra, J. C. Nigg
Tomato apex necrosis virus (species Tomato marchitez virus, genus Torradovirus, family Secoviridae) causes a severe tomato disease in Mexico. One distinctive feature of torradoviruses compared to other members of the family Secoviridae is the presence of an additional open reading frame (ORF) in genomic RNA2 (denominated RNA2-ORF1), located upstream of ORF2. RNA2-ORF2 encodes a polyprotein that is processed into a putative movement protein and three capsid proteins (CPs). The RNA2-ORF1 protein has homologues only among other torradoviruses, and so far, no function has been associated to it. We used recombinant and mutant ToANV clones to investigate the role of the RNA2-ORF1 protein in various aspects of the virus infection cycle. The lack of a functional RNA2-ORF1 resulted in inability to systemically infect Nicotiana benthamiana and tomato plants, but both positive and negative strand RNA1 and RNA2 accumulated locally in agroinfiltrated areas in N. benthamiana plants, indicating that the RNA2-ORF1 mutants were replication-competent. Furthermore, a mutant with a deletion in RNA2-ORF1 was competent for virion formation and for cell-to-cell movement in the cells immediately surrounding the initial infection site. However, immunological detection of the ToANV CPs in the agroinfiltrated areas showed that this mutant was not detected in the sieve elements even if the surrounding parenchymatic cells were ToANV positive, suggesting a role for the RNA2-ORF1 protein in processes occurring prior to phloem uploading, including efficient spread in inoculated leaves. This article is protected by copyright. All rights reserved.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1111/mpp.12615

You might also like
Never Miss Important Research

Researcher is an app designed by academics, for academics. Create a personalised feed in two minutes.
Choose from over 15,000 academics journals covering ten research areas then let Researcher deliver you papers tailored to your interests each day.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.