Biological characterization of citrus tristeza closterovirus isolates by in vitro cultures
Citrus tristeza closterovirus (CTV - EPPO A2 quarantine pest) has numerous strains differing in biological and serological properties, dsRNA patterns and genome sequences. Despite significant progress made at molecular level, biological characterization of field isolates is still necessary, in particular to control the spread of the most damaging strains. Biological characterization (inoculation to indicators) is expensive and time-consuming. Studies were carried out in Spain to observe in vitro the effects of five CTV isolates on the morphogenesis of stem fragments from Mexican lime (Citrus aurantiifolia), sweet orange (C. sinensis), grapefruit (C. paradisi), Citrus excelsa and alemow (C. macrophylla). Results showed that morphogenesis (regeneration of roots and shoots) of stem fragments is modified as a result of CTV infection. In addition, the CTV isolates caused effects which could be correlated with the in vivo effects observed in biological testing. Mexican lime and grapefruit gave the best results, and could be used to discriminate the isolates. The authors felt that the evaluation of morphogenesis response of stem fragments of Mexican lime and grapefruit can be used as an additional tool in the biological characterization of CTV isolates.
Sources
Ghorbel, R; Navarro, L.; Duran-Vila, N. (1998) Biological characterization of citrus tristeza virus isolates by in vitro cultures.
Plant Pathology, 47(3), 333-340.