Occurrence of a new stolbur strain in tobacco in Serbia

Abstract

Stolbur phytoplasmas are associated with several important diseases on different crops worldwide. Although stolbur phytoplasmas are known to have low variability in 16S rDNA, some RFLP and single nucleotide polymorphisms among them were reported. To verify the presence and determine the identity of phytoplasmas present in tobacco in Serbia, PCR-RFLP and sequence analyses were performed on DNA extracts from 17 symptomatic plants. RFLP profiles of all positive samples except one were identical to those of 16SrXII-A subgroup, while strain 284/09 showed slightly different profile than others. The obtained results confirm presence and also show that there is variability in 16S rDNA among stolbur phytoplasmas in tobacco in Serbia. The revealed SNP was never reported in stolbur phytoplasmas before and is not present in any sequence deposited in the Genbank, which results in a unique RFLP profile. It is confirmed that the SNP is inside the 16S rDNA and is confirmed with PCR-RFLP analyses on three separate extractions, of which one was of the seedling after grafting with infected plant tissue. Relation of the SNP in the 16S rDNA with possible variations in other marker genes or some ecological properties of the strain are still to be defined.