Cucurbit chlorotic yellows virus p22 is a suppressor of local RNA silencing

  • Chrysoula G. Orfanidou
  • Matthaios M. Mathioudakis
  • Konstantina Katsarou
  • Ioannis Livieratos
  • Nikolaos Katis
  • Varvara I. MaliogkaEmail author
Original Article


RNA silencing is a major antiviral mechanism in plants, which is counteracted by virus-encoded proteins with silencing suppression activity. ORFs encoding putative silencing suppressor proteins that share no structural or sequence homology have been identified in the genomes of four criniviruses. In this study, we investigated the RNA silencing suppression activity of several proteins encoded by the RNA1 (RdRp, p22) and RNA2 (CP, CPm and p26) of cucurbit chlorotic yellows virus (CCYV) using co-agroinfiltration assays on Nicotiana benthamiana plants. Our results indicate that p22 is a suppressor of local RNA silencing that does not interfere with cell-to-cell movement of the RNA silencing signal or with systemic silencing. Furthermore, comparisons of the suppression activity of CCYV p22 with that of two other well-known crinivirus suppressors (CYSDV p25 and ToCV p22) revealed that CCYV p22 is a weaker suppressor of local RNA silencing than the other two proteins. Finally, a comparative sequence analysis of the p22 genes of seven Greek CCYV isolates was performed, revealing a high level of conservation. Taken together, our research advances our knowledge about plant-virus interactions of criniviruses, an emergent group of pathogens that threatens global agriculture.


Closteroviridae Crinivirus CCYV RNA silencing suppression 



Ms. C. Orfanidou is a recipient of Scholarship by the General Secretariat for Research and Technology (GSRT) and the Hellenic Foundation for Research and Innovation (HFRI) (Scholarship Code: 984). Dr. Konstantina Katsarou was supported by a grant from the General Secretary for Research and Technology of Greece, Infrastructures Support Program [MIS5002803] “PlantUP”.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Plant Pathology Laboratory, Faculty of Agriculture, Forestry and Natural Environment, School of AgricultureAristotle University of ThessalonikiThessalonikiGreece
  2. 2.Department of Sustainable AgricultureMediterranean Agronomic Institute of Chania, Alsylio AgrokepioChaniaGreece
  3. 3.Department of BiologyUniversity of CreteHeraklionGreece
  4. 4.Institute for Olive tree, Subtropical crops and Viticulture, Plant Pathology LaboratoryHellenic Agricultural Organization-“DEMETER”ChaniaGreece

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