The Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral Defense

The N-terminal region of the Ourmia melon virus (OuMV) coat protein (CP) contains a short lysine/arginine-rich (KR) region. By alanine scanning mutagenesis, we showed that the KR region influences pathogenicity and virulence of OuMV without altering viral particle assembly. A mutant, called OuMV6710...

Full description

Bibliographic Details
Main Authors: Marika Rossi, Marta Vallino, Simona Abbà, Marina Ciuffo, Raffaella Balestrini, Andrea Genre, Massimo Turina
Format: Article
Language:English
Published: The American Phytopathological Society 2015-01-01
Series:Molecular Plant-Microbe Interactions
Online Access:https://apsjournals.apsnet.org/doi/10.1094/MPMI-07-14-0197-R
_version_ 1811261366853435392
author Marika Rossi
Marta Vallino
Simona Abbà
Marina Ciuffo
Raffaella Balestrini
Andrea Genre
Massimo Turina
author_facet Marika Rossi
Marta Vallino
Simona Abbà
Marina Ciuffo
Raffaella Balestrini
Andrea Genre
Massimo Turina
author_sort Marika Rossi
collection DOAJ
description The N-terminal region of the Ourmia melon virus (OuMV) coat protein (CP) contains a short lysine/arginine-rich (KR) region. By alanine scanning mutagenesis, we showed that the KR region influences pathogenicity and virulence of OuMV without altering viral particle assembly. A mutant, called OuMV6710, with three basic residue substitutions in the KR region, was impaired in the ability to maintain the initial systemic infection in Nicotiana benthamiana and to infect both cucumber and melon plants systemically. The integrity of this protein region was also crucial for encapsidation of viral genomic RNA; in fact, certain mutations within the KR region partially compromised the RNA encapsidation efficiency of the CP. In Arabidopsis thaliana Col-0, OuMV6710 was impaired in particle accumulation; however, this phenotype was abolished in dcl2/dcl4 and dcl2/dcl3/dcl4 Arabidopsis mutants defective for antiviral silencing. Moreover, in contrast to CPwt, in situ immunolocalization experiments indicated that CP6710 accumulates efficiently in the spongy mesophyll tissue of infected N. benthamiana and A. thaliana leaves but only occasionally infects palisade tissues. These results provided strong evidence of a crucial role for OuMV CP during viral infection and highlighted the relevance of the KR region in determining tissue tropism, host range, pathogenicity, and RNA affinity, which may be all correlated with a possible CP silencing-suppression activity.
first_indexed 2024-04-12T19:02:11Z
format Article
id doaj.art-6d796a86d4d040e798841f48a7031d12
institution Directory Open Access Journal
issn 0894-0282
1943-7706
language English
last_indexed 2024-04-12T19:02:11Z
publishDate 2015-01-01
publisher The American Phytopathological Society
record_format Article
series Molecular Plant-Microbe Interactions
spelling doaj.art-6d796a86d4d040e798841f48a7031d122022-12-22T03:20:07ZengThe American Phytopathological SocietyMolecular Plant-Microbe Interactions0894-02821943-77062015-01-01281304110.1094/MPMI-07-14-0197-RThe Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral DefenseMarika RossiMarta VallinoSimona AbbàMarina CiuffoRaffaella BalestriniAndrea GenreMassimo TurinaThe N-terminal region of the Ourmia melon virus (OuMV) coat protein (CP) contains a short lysine/arginine-rich (KR) region. By alanine scanning mutagenesis, we showed that the KR region influences pathogenicity and virulence of OuMV without altering viral particle assembly. A mutant, called OuMV6710, with three basic residue substitutions in the KR region, was impaired in the ability to maintain the initial systemic infection in Nicotiana benthamiana and to infect both cucumber and melon plants systemically. The integrity of this protein region was also crucial for encapsidation of viral genomic RNA; in fact, certain mutations within the KR region partially compromised the RNA encapsidation efficiency of the CP. In Arabidopsis thaliana Col-0, OuMV6710 was impaired in particle accumulation; however, this phenotype was abolished in dcl2/dcl4 and dcl2/dcl3/dcl4 Arabidopsis mutants defective for antiviral silencing. Moreover, in contrast to CPwt, in situ immunolocalization experiments indicated that CP6710 accumulates efficiently in the spongy mesophyll tissue of infected N. benthamiana and A. thaliana leaves but only occasionally infects palisade tissues. These results provided strong evidence of a crucial role for OuMV CP during viral infection and highlighted the relevance of the KR region in determining tissue tropism, host range, pathogenicity, and RNA affinity, which may be all correlated with a possible CP silencing-suppression activity.https://apsjournals.apsnet.org/doi/10.1094/MPMI-07-14-0197-R
spellingShingle Marika Rossi
Marta Vallino
Simona Abbà
Marina Ciuffo
Raffaella Balestrini
Andrea Genre
Massimo Turina
The Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral Defense
Molecular Plant-Microbe Interactions
title The Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral Defense
title_full The Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral Defense
title_fullStr The Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral Defense
title_full_unstemmed The Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral Defense
title_short The Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral Defense
title_sort importance of the kr rich region of the coat protein of ourmia melon virus for host specificity tissue tropism and interference with antiviral defense
url https://apsjournals.apsnet.org/doi/10.1094/MPMI-07-14-0197-R
work_keys_str_mv AT marikarossi theimportanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT martavallino theimportanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT simonaabba theimportanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT marinaciuffo theimportanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT raffaellabalestrini theimportanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT andreagenre theimportanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT massimoturina theimportanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT marikarossi importanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT martavallino importanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT simonaabba importanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT marinaciuffo importanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT raffaellabalestrini importanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT andreagenre importanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense
AT massimoturina importanceofthekrrichregionofthecoatproteinofourmiamelonvirusforhostspecificitytissuetropismandinterferencewithantiviraldefense