Agriculturae Conspectus Scientificus, Vol 81, No 1 (2016)

Efficiency of Citrus Tristeza Virus Isolates in Inducing Early Systemic Infection in Different Citrus Hosts

Katarina HANČEVIĆ, Iva ŠUŠIĆ, Tomislav RADIĆ

Pages: 27-33


Citrus tristeza virus (CTV) is the most destructive citrus pathogen. The knowledge about how its infectivity is accomplished, time in which CTV causes systemic infection after transfer to the host plant and the relation between virus invasion and CTV pathogenicity is very scarce. The main objective of this study was to analyse whether different CTV genotypes vary in efficiency to cause systemic viral infection. Three weeks post-inoculation, set of seven host-plant citrus species were checked for CTV systemic infection. Among seven CTV isolates tested, six of them were monophyletic according to the p25 gene and previously biologically characterised. For one polyphyletic virus isolate the pathogenicity was established in this study. Our results showed that the transmission of virus and systemic infection is correlated with pathogenicity of CTV isolates, namely stem-pitting syndrome (SP). In three weeks CTV-SP isolates achieved systemic infection detectible by DTBA serological test. Polyphyletic isolate (composed of Gp 3b and Gp 5) that caused 100% infection, after biological characterization showed severe form of SP-syndrome. Monophyletic isolates belonging to Gp4, Gp3a and Gp2, which were determined as SP-CTV isolates, also achieved high percentages of systemic infection, respectively. On the contrary to severe SP isolates, isolates that are not related to appearance of SP disease symptoms were less efficient in accomplishing systemic virus infection. These results lead us to consider the aggressiveness of SP-CTV isolates as an important factor in processes of accomplishing early systemic plant infection.


Citrus tristeza virus, systemic infection, bioindicators, stem-pitting symptoms

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