'Candidatus Phytoplasma pini', a novel taxon from Pinus silvestris and Pinus halepensis

1 Biologische Bundesanstalt für Land- und Forstwirtschaft, Institut für Pflanzenschutz im Obstbau, D-69211 Dossenheim, Germany 2 Laboratori Sanitat Vegetal, Generalitat de Catalunya, Barcelona, Spain 3 Real Jardín Botánico, CSIC, Madrid, Spain 4 Landesanstalt für Pflanzenschutz, D-70197 Stuttgart, Germany 5 Universität Heidelberg, Heidelberger Institut für Pflanzenwissenschaften, D-69120 Heidelberg, Germany Correspondence Erich Seemüller E.Seemueller{at}bba.de Pinus silvestris and Pinus halepensis trees grown in Germany and Spain, respectively, showing abnormal shoot branching, dwarfed needles and other symptoms were examined for the presence of plant-pathogenic mollicutes (phytoplasmas). While phytoplasmas could not be detected unambiguously with microscopical methods, PCR amplification using universal phytoplasma primers yielded positive results. Samples collected from symptomatic and non-symptomatic plant parts of both symptomatic Pinus silvestris and Pinus halepensis trees tested positive. Also, surrounding non-symptomatic trees proved to be phytoplasma-infected. Comparisons revealed that the 16S rRNA gene sequences of the phytoplasmas identified in Pinus silvestris and Pinus halepensis were nearly identical. However, the pine phytoplasma is only distantly related to other phytoplasmas. The closest relatives are members of the palm lethal yellowing and rice yellow dwarf groups and ‘ Candidatus Phytoplasma castaneae’, which share between 94·5 and 96·6 % 16S rRNA gene sequence similarity. From these data it can be concluded that the phytoplasmas identified in the two Pinus species represent a coherent but discrete taxon; it is proposed that this taxon be distinguished at putative species level under the name ‘ Candidatus Phytoplasma pini’. The GenBank/EMBL/DDBJ accession numbers for the P1/P7 amplimer (16S rRNA gene and 16S/23S rRNA spacer region) of phytoplasma strains Pin127S R , Pin190S and PinG are AJ632155 , AJ632156 and AJ310849 , respectively.