Plant Cell Reports

, Volume 27, Issue 1, pp 57–66

Genetic transformation of sweet orange with the coat protein gene of Citrus psorosis virus and evaluation of resistance against the virus

  • María Cecilia Zanek
  • Carina Andrea Reyes
  • Magdalena Cervera
  • Eduardo José Peña
  • Karelia Velázquez
  • Norma Costa
  • Maria Inés Plata
  • Oscar Grau
  • Leandro Peña
  • María Laura García
Genetic Transformation and Hybridization

DOI: 10.1007/s00299-007-0422-8

Cite this article as:
Zanek, M.C., Reyes, C.A., Cervera, M. et al. Plant Cell Rep (2008) 27: 57. doi:10.1007/s00299-007-0422-8

Abstract

Citrus psorosis is a serious viral disease affecting citrus trees in many countries. Its causal agent is Citrus psorosis virus (CPsV), the type member of genus Ophiovirus. CPsV infects most important citrus varieties, including oranges, mandarins and grapefruits, as well as hybrids and citrus relatives used as rootstocks. Certification programs have not been sufficient to control the disease and no sources of natural resistance have been found. Pathogen-derived resistance (PDR) can provide an efficient alternative to control viral diseases in their hosts. For this purpose, we have produced 21 independent lines of sweet orange expressing the coat protein gene of CPsV and five of them were challenged with the homologous CPV 4 isolate. Two different viral loads were evaluated to challenge the transgenic plants, but so far, no resistance or tolerance has been found in any line after 1 year of observations. In contrast, after inoculation all lines showed characteristic symptoms of psorosis in the greenhouse. The transgenic lines expressed low and variable amounts of the cp gene and no correlation was found between copy number and transgene expression. One line contained three copies of the cp gene, expressed low amounts of the mRNA and no coat protein. The ORF was cytosine methylated suggesting a PTGS mechanism, although the transformant failed to protect against the viral load used. Possible causes for the failed protection against the CPsV are discussed.

Keywords

Citrus psorosis virus PDR Post-transcriptional gene silencing Citrus Transgenic trees 

Abbreviations

CPsV

Citrus psorosis virus

CP

Coat protein

TAS-ELISA

Triple sandwich immunoassay

PDR

Pathogen-derived resistance

CaMV

Cauliflowermosaic virus

AMV

Alfalfa mosaic virus

nos

Nopaline synthase gene

OD

Optical density

dpi

Days post inoculation

C-I

Infected control

C-NI

Non-infected control

PTGS

Post-transcriptional gene silencing

CTV

Citrus tristeza virus

GFLV

Grapevine fan-leaf virus

TSWV

Tomato spotted wilt virus

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • María Cecilia Zanek
    • 1
  • Carina Andrea Reyes
    • 1
  • Magdalena Cervera
    • 3
  • Eduardo José Peña
    • 1
  • Karelia Velázquez
    • 1
  • Norma Costa
    • 2
  • Maria Inés Plata
    • 2
  • Oscar Grau
    • 1
  • Leandro Peña
    • 3
  • María Laura García
    • 1
  1. 1.Facultad de Ciencias ExactasInstituto de Bioquímica y Biología Molecular (IBBM), U.N.L.P.La PlataArgentina
  2. 2.Estación Experimental Agropecuaria, INTAConcordiaArgentina
  3. 3.Dpto de Protección Vegetal y BiotecnologiaInstituto Valenciano de Investigaciones Agrarias (IVIA)MoncadaSpain