title: Agroinoculation of Citrus tristeza virus causes systemic infection and symptoms in the presumed nonhost Nicotiana benthamiana.
abstract: Citrus tristeza virus (CTV) naturally infects only some citrus species and relatives and within these it only invades phloem tissues. Failure to agroinfect citrus plants and the lack of an experimental herbaceous host hindered development of a workable genetic system. A full-genome cDNA of CTV isolate T36 was cloned in binary plasmids and was used to agroinfiltrate Nicotiana benthamiana leaves, with or without coinfiltration with plasmids expressing different silencing-suppressor proteins. A time course analysis in agroinfiltrated leaves indicated that CTV accumulates and moves cell-to-cell for at least three weeks postinoculation (wpi), and then, it moves systemically and infects the upper leaves with symptom expression. Silencing suppressors expedited systemic infection and often increased infectivity. In systemically infected Nicotiana benthamiana plants, CTV invaded first the phloem, but after 7 wpi, it was also found in other tissues and reached a high viral titer in upper leaves, thus allowing efficient transmission to citrus by stem-slash inoculation. Infected citrus plants showed the symptoms, virion morphology, and phloem restriction characteristic of the wild T36 isolate. Therefore, agroinfiltration of Nicotiana benthamiana provided the first experimental herbaceous host for CTV and an easy and efficient genetic system for this closterovirus.
authors: Centro de Protección Vegetal y Biotecnologia, IVIA, Moncada, Valencia 46113, Spain.
authors: Silvia
authors: S
authors: Ambrós
authors: Choaa
authors: C
authors: El-Mohtar
authors: Susana
authors: S
authors: Ruiz-Ruiz
authors: Leandro
authors: L
authors: Peña
authors: José
authors: J
authors: Guerri
authors: William O
authors: WO
authors: Dawson
authors: Pedro
authors: P
authors: Moreno
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000821:virology; D002957:Citrus / Q000821:virology*; D017790:Closterovirus / Q000235:genetics / Q000472:pathogenicity*; D004279:DNA, Viral / Q000235:genetics; D020868:Gene Silencing; D005821:Genetic Techniques; D005822:Genetic Vectors; D016679:Genome, Viral; D054884:Host-Pathogen Interactions / Q000235:genetics; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000821:virology; D030821:Plants, Genetically Modified; D010957:Plasmids / Q000235:genetics; D013045:Species Specificity; D014026:Nicotiana / Q000235:genetics / Q000821:virology*; D014774:Virulence
chemical_list: D004279:DNA, Viral