'Candidatus Phytoplasma asteris', a novel phytoplasma taxon associated with aster yellows and related diseases.
Aster yellows (AY) group (16SrI) phytoplasmas are associated with over 100 economically important diseases worldwide and represent the most diverse and widespread phytoplasma group. Strains that belong to the AY group form a phylogenetically discrete subclade within the phytoplasma clade and are related most closely to the stolbur phytoplasma subclade, based on analysis of 16S rRNA gene sequences. AY subclade strains are related more closely to their culturable relatives, Acholeplasma spp., than any other phytoplasmas known. Within the AY subclade, six distinct phylogenetic lineages were revealed. Congruent phylogenies obtained by analyses of tuf gene and ribosomal protein (rp) operon gene sequences further resolved the diversity among AY group phytoplasmas. Distinct phylogenetic lineages were identified by RFLP analysis of 16S rRNA, tuf or rp gene sequences. Ten subgroups were differentiated, based on analysis of rp gene sequences. It is proposed that AY group phytoplasmas represent at least one novel taxon. Strain OAY, which is a member of subgroups 16SrI-B, rpI-B and tufI-B and is associated with evening primrose (Oenothera hookeri) virescence in Michigan, USA, was selected as the reference strain for the novel taxon 'Candidatus Phytoplasma asteris'. A comprehensive database of diverse AY phytoplasma strains and their geographical distribution is presented.
USDA-ARS Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA.
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Lee
Insect Biocontrol Laboratory, Beltsville, MD 20705, USA.
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Gundersen-Rindal
USDA-ARS Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA.
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Davis
USDA-ARS Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA.
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Bottner
Dept Biologia, Difesa e Biotecnologie Agro-Forestali, University of Basilicata, 85100 Potenza, Italy.
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Marcone
Biologische Bundesanstalt, Institut für Pflanzenschutz im Obstbau, D-69221 Dossenheim, Germany.
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Seemüller
D000127:Acholeplasma / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000737:chemistry / Q000302:isolation & purification; D020459:Genes, rRNA; D008969:Molecular Sequence Data; D009876:Operon; D010802:Phylogeny; D045582:Phytoplasma / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D010935:Plant Diseases / Q000382:microbiology*; D010944:Plants / Q000382:microbiology; D012150:Polymorphism, Restriction Fragment Length; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012269:Ribosomal Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012269:Ribosomal Proteins