Identification of “stolbur” phytoplasmas in Petunia hybrida seedlings

To verify the possibility of seed transmission of “stolbur” phytoplasmas in spreading type petunia plants, the phytoplasma presence was investigated in seedlings of three cultivars prepared by sowing commercial seeds grown under insect-proof conditions. In two of these cultivars 16 and 26 seedlings resulted positive to phytoplasma presence by nested PCR on 16S rRNA gene. This result indicated that phytoplasmas are transmitted by seed in spreading type petunia plants. Through sequencing of the nested PCR products, 10 strains were identified as related to “stolbur” and grouped into ‘Candidatus Phytoplasma solani’ clade by phylogenetic analysis. This is the first report of seed transmission of “stolbur” phytoplasma in Petunia hybrida.