Identification of new isolates of Turnip mosaic virus that cluster with less common viral strains.

ABSTRACT

Turnip mosaic virus (TuMV) was found infecting cultivated brassicas and wild and cultivated ornamental Brassicaceae plants in different regions of Spain. Five new TuMV isolates, originating from different host plant species (Brassica cretica, Brassica juncea, Brassica napus, Eruca vesicaria subsp. sativa and Sisymbrium orientale), have been identified. The nucleotide sequences of the coat protein (CP) genes of the five isolates were determined. Phylogenetic analysis of the CP sequences showed that the five isolates grouped into two different clusters. The three isolates from the central region of Spain clustered with a previously reported Pisum sativum isolate from southeastern Spain, whereas the other two isolates from the eastern region clustered with two Italian and two Greek isolates. Both clusters were genetically distinct and belonged to the multi-lineage group OBR. The OBR group contains mainly TuMV isolates from hosts other than Brassica spp. and Raphanus sativus and mostly originating from Mediterranean countries. These new sequences provide further phylogenetic resolution of the OBR group. Although new TuMV isolates have been found in Spain, they were not associated with any serious disease outbreaks.