Detection of Phytoplasma belonging to the 16SrXXI group in Scott pine and mountain pine

Abstract

One of the reasons for the deterioration of coniferous stands condition in a number of European countries is associated with their infection with phytoplasmas (obligate intracellular pathogens) — bacteria lacking a cell wall. The aim of the work is to identify the presence of phytoplasma infection in samples of Scots pine (Pinus sylvestris L.) and mountain pine (Pinus mugo Turra) collected in the Moscow and Samara regions, which had characteristic symptoms of the disease, and to determine the taxonomic affiliation of the phytoplasm. Phytoplasma was detected using direct and nested PCR with primer pairs P1/16S-Sr and R16F2n/R16R2 respectively. Phytoplasma DNA was found in six of the seven pine specimens, including an asymptomatic one. Analysis of restriction fragment length’s polymorphism after digestion of DNA amplicons with restriction endonucleases AluI, MseI, HhaI, HpaII, HaeIII, RsaI, and TaqI indicated the similarity of Russian strains of Scotch pine and mountain pine phytoplasmas to Lithuanian strains of PineLRN and PineBLD of mountain pine phytoplasma (GenBank Accession Number MK089821 and MK089819, respectively) identified as ‘Candidatus Phytoplasma pini’ (subgroup 16SrXXI-A). A phytoplasma related to this species has been registered on the territory of the Russian Federation for the first time.