Visual inspections of elm trees in south Moravia in 1997-2007 revealed a rare occurrence of plants with smaller and cowl-forming leaves on some twigs, i.e. a feature resembling witches'-broom disease observed on the end of twigs. The presence of phytoplasma-like bodies was observed by transmission electron microscopy of phloem tissue. On the other hand, no phytoplasmas were found in asymptomatic trees. Nucleic acids extracted from these plants were used in nested-PCR assays with primers amplifying 16S rRNA sequences specific for phytoplasmas. Sequence analyses of the 16S-23S ribosomal operon (1852 bp) allowed for the classification of the detected phytoplasmas in the elm yellows group, but its position remained on the boundary of the 16SrV-A and 16SrV-C ribosomal subgroups. Sequence analyses of the ribosomal protein of the rpl22-rps3 and secY genes lead to further classification and revealed the phytoplasmas' affiliations to the 'Candidates Phytoplasma ulmi'. Some exceptions in unique oligonucleotide sequences defined for 'Ca. Phytoplasma ulmi' were found in the Czech isolate. This is the northernmost confirmed occurrence of phytoplasma on elm trees within Europe.
- MeSH
- bakteriální proteiny genetika MeSH
- DNA bakterií genetika MeSH
- elektronová mikroskopie MeSH
- fylogeneze MeSH
- molekulární sekvence - údaje MeSH
- nemoci rostlin mikrobiologie MeSH
- Phytoplasma MeSH
- ribozomální DNA genetika MeSH
- RNA ribozomální 16S genetika MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- Ulmus mikrobiologie MeSH
- Geografické názvy
- Česká republika MeSH
