title: A 5'-proximal region of the Citrus tristeza virus genome encoding two leader proteases is involved in virus superinfection exclusion.
abstract: Superinfection exclusion (SIE), a phenomenon in which a primary virus infection prevents a secondary infection with the same or closely related virus, has been observed with various viruses. Earlier we demonstrated that SIE by Citrus tristeza virus (CTV) requires viral p33 protein. In this work we show that p33 alone is not sufficient for virus exclusion. To define the additional viral components that are involved in this phenomenon, we engineered a hybrid virus in which a 5'-proximal region in the genome of the T36 isolate containing coding sequences for the two leader proteases L1 and L2 has been substituted with a corresponding region from the genome of a heterologous T68-1 isolate. Sequential inoculation of plants pre-infected with the CTV L1L2T68 hybrid with T36 CTV resulted in superinfection with the challenge virus, which indicated that the substitution of the L1-L2 coding region affected SIE ability of the virus.
authors.affiliation: University of Florida, Plant Pathology Department, Gainesville, FL 32611, USA.
authors.forename: Osama O
authors.initials: OO
authors.lastname: Atallah
authors.affiliation: University of Florida, Plant Pathology Department, Gainesville, FL 32611, USA.
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Kang
authors.affiliation: University of Florida, Plant Pathology Department, Gainesville, FL 32611, USA.
authors.forename: Choaa A
authors.initials: CA
authors.lastname: El-Mohtar
authors.affiliation: University of Florida, Plant Pathology Department, Gainesville, FL 32611, USA.
authors.forename: Turksen
authors.initials: T
authors.lastname: Shilts
authors.affiliation: University of Florida, Plant Pathology Department, Gainesville, FL 32611, USA.
authors.forename: María
authors.initials: M
authors.lastname: Bergua
authors.affiliation: University of Florida, Plant Pathology Department, Gainesville, FL 32611, USA. Electronic address: svetlana@ufl.edu.
authors.forename: Svetlana Y
authors.initials: SY
authors.lastname: Folimonova
mesh_terms: D002957:Citrus / Q000502:physiology*; D017790:Closterovirus / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D016679:Genome, Viral; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000821:virology*; D015163:Superinfection / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D014764:Viral Proteins; D010447:Peptide Hydrolases
keywords: Citrus tristeza virus; Viral proteases; Viral superinfection exclusion