'Candidatus Phytoplasma fragariae', a novel phytoplasma taxon discovered in yellows diseased strawberry, Fragaria x ananassa

Abstract

Symptoms of general stunting and yellowing of leaves were observed in diseased cultivated strawberry (Fragaria x ananassa Duchesne) in Lithuania. Analysis of 16S rRNA gene sequences amplified by PCR indicated that the symptoms were associated with infection by a phytoplasma, designated strawberry yellows (StrawY) phytoplasma. Phylogenetic analysis of 16S rRNA gene sequences indicated that StrawY phytoplasma, 'Candidatus Phytoplasma australiense', 'Candidatus Phytoplasma asteris', stolbur phytoplasma and 'Candidatus Phytoplasma japonicum' shared a common ancestor, but were mutually distinct. Nucleotide sequence alignments of a 1.3 kb 16S rRNA gene sequence fragment revealed that StrawY phytoplasma shared 97.4 % or less similarity with previously described 'Candidatus Phytoplasma' species. These results, in addition to natural host and geographical occurrence, support the recognition of StrawY phytoplasma as a representative of a novel taxon, 'Candidatus Phytoplasma fragariae'.