Molecular characterization of “bois noir” phytoplasma strains in a single vineyard in central Serbia

Grapevine “bois noir” (BN) is a phytoplasma disease widely present in large numbers of viticultural regions of the world, and it can result in heavy reductions in yield and grape juice quality. BN is associated with the presence of ‘Candidatus Phytoplasma solani’ (BN), transmitted from herbaceous plants to grapevine by polyphagous insect vectors. In the Euro-Mediterranean Region, phloem-feeding Hemiptera of the Cixiidae family are the vectors of “stolbur” phytoplasmas and in particular, the plant hopper Hyalesthes obsoletus Signoret is the main responsible for BN transmission to grapevine. Adult of H. obsoletus can feed on various herbaceous plants, but only a few species are selected to complete their life cycle. The different ability to induce epidemic outbreak is often associated with molecularly differentiable phytoplasmas usually enclosed in the same taxon. A study was therefore carried out to verify the presence of molecular variability of BN strains in a restricted environment such as a vineyard located in the central Serbia planted with different grapevine varieties.