Genetic and molecular variability of a Turnip mosaic virus population from horseradish (Cochlearia armoracia L.).

ABSTRACT

Variability and genetic structure of a novel Turnip mosaic virus (TuMV) population from horseradish (Cochlearia armoracia L.) were examined. Over 60 horseradish plants were tested to identify a total of 28 TuMV isolates, constituting the Cochlearia ARmoracia (CAR) TuMV population. Two subgroups of the CAR TuMV isolates could be distinguished subgroup N did not infect oilseed rape (Brassica napus var. oleifera) cv. Westar plants, while subgroup A infected these plants systemically. Two types of infection of oilseed rape plants were induced by inoculation with the CAR TuMV isolates systemic mosaic infection and systemic necrotic lesions. The complete sequences of isolates CAR37 (subgroup N) and CAR37A (subgroup A) were determined and compared. The sequences of HC-Pro and CP genes of CAR37 and CAR37A and other isolates of TuMV from other countries were compared to provide some insight into their relatedness. CAR37A, initially regarded as a variant, proved to be very different from CAR37. Re-sequencing after repeated passages confirmed the genetic stability of both isolates.