title: Resistance to Citrus psorosis virus in transgenic sweet orange plants is triggered by coat protein-RNA silencing.
abstract: The lack of naturally occurring resistance to Citrus psorosis virus (CPsV) has demanded exploitation of a transgenic approach for the development of CPsV-resistant sweet orange plants. Transgenic sweet orange plants producing intron-hairpin RNA transcripts (ihpRNA) corresponding to viral cp, 54K or 24K genes were generated and analyzed at the molecular and phenotypic levels. Two independent CPsV challenge assays demonstrated that expression of ihpRNA derived from the cp gene (ihpCP) provided a high level of virus resistance, while those derived from 54K and 24K genes (ihp54K and ihp24K) provided partial or no resistance. The presence of small interfering RNA molecules (siRNAs) in the ihpCP transgenic sweet orange plants prior to virus challenge, indicated that CPsV resistance was due to pre-activated RNA silencing, but siRNAs accumulation level was not directly correlated to the degree of the triggered virus resistance among the different lines. However, pre-activation of the RNA-silencing machinery and a certain minimum accumulation level of siRNA molecules targeting the viral genome are key factors for creating virus-resistant plants. This is the first report of resistance in citrus plants against a negative-strand RNA virus as CPsV.
authors.affiliation: Instituto de Biotecnología y Biología Molecular, CCT-La Plata, CONICET-UNLP, La Plata, Buenos Aires, Argentina.
authors.forename: Carina Andrea
authors.initials: CA
authors.lastname: Reyes
authors.forename: Agustina
authors.initials: A
authors.lastname: De Francesco
authors.forename: Eduardo José
authors.initials: EJ
authors.lastname: Peña
authors.forename: Norma
authors.initials: N
authors.lastname: Costa
authors.forename: María Inés
authors.initials: MI
authors.lastname: Plata
authors.forename: Lorena
authors.initials: L
authors.lastname: Sendin
authors.forename: Atilio Pedro
authors.initials: AP
authors.lastname: Castagnaro
authors.forename: María Laura
authors.initials: ML
authors.lastname: García
mesh_terms: D015139:Blotting, Southern; D036022:Capsid Proteins / Q000737:chemistry / Q000378:metabolism; D002957:Citrus / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay; D054884:Host-Pathogen Interactions; D008969:Molecular Sequence Data; D010942:Plant Viruses / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000821:virology*; D034622:RNA Interference; D034741:RNA, Small Interfering
chemical_list: D036022:Capsid Proteins; D034741:RNA, Small Interfering